{
  "dataset": {
    "name": "Stormwater Runoff Reference Dataset 2026",
    "publisher": "Huntsville Yard Drainage Research",
    "site": "https://huntsvilleyarddrainage.com/",
    "page": "https://huntsvilleyarddrainage.com/research/stormwater-runoff-calculator/",
    "version": "1.0.0",
    "date_modified": "2026-07-25",
    "record_count": 567,
    "verification_tiers": {
      "★": "Read directly against the issuing agency or original data producer.",
      "◆": "Reproducibly calculated from one or more cited ★ records using the stated formula."
    },
    "record_type_counts": {
      "derived_average_intensity": 50,
      "exact_unit_conversion": 3,
      "gross_rainfall_scenario": 15,
      "precipitation_frequency_depth": 190,
      "regulatory_adoption": 1,
      "runoff_coefficient_frequency_factor": 16,
      "runoff_coefficient_range": 284,
      "source_provenance": 6,
      "source_reconciliation": 2
    },
    "description": "A versioned compilation of Rational Method runoff-coefficient records from six official U.S. drainage manuals, exact U.S. customary runoff conversions, four published frequency-adjustment series, 190 Huntsville PDS-based precipitation-frequency central estimates, 50 derived short-duration average intensities, 15 reproducible gross-rainfall scenarios, source provenance, the City of Huntsville's 2020 manual-adoption record, and two primary-source reconciliation findings.",
    "scope": {
      "national": "Unit conversions and coefficient comparison across FHWA, TxDOT, ODOT, WSDOT, NCTCOG iSWM, and City of Huntsville publications.",
      "local": "Huntsville, Alabama point/reference precipitation data and City design criteria.",
      "not_in_scope": "Pipe, inlet, swale, detention, trench-drain, French-drain, or outlet sizing."
    },
    "methodology_summary": [
      "Source values were transcribed directly from primary agency publications on July 25, 2026.",
      "Manual categories were preserved in record-level parameter text; the visible page crosswalk uses disclosed category mapping.",
      "Ranges were not averaged. Slope and soil classes were retained where the source published them.",
      "Derived values and coefficient-free gross-rainfall scenarios were generated programmatically from cited source records.",
      "PDS average recurrence interval was not converted by simple reciprocal to annual exceedance probability; NOAA states that inverse AEP is not PDS ARI.",
      "Where the City of Huntsville manual conflicts with itself, both values are retained."
    ],
    "primary_sources": [
      {
        "name": "NIST Handbook 44 (2026), Appendix C",
        "url": "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c"
      },
      {
        "name": "FHWA HEC-22, 4th edition",
        "url": "https://www.fhwa.dot.gov/engineering/hydraulics/pubs/hif24006.pdf"
      },
      {
        "name": "TxDOT Hydraulic Design Manual, Section 12",
        "url": "https://www.txdot.gov/manuals/des/hyd/chapter-4--hydrology/section-12--rational-method.html"
      },
      {
        "name": "ODOT Hydraulics Manual, Appendix F",
        "url": "https://www.oregon.gov/odot/hydraulics/Docs_Hydraulics_Manual/Hydraulics-07-F.pdf"
      },
      {
        "name": "WSDOT Hydraulics Manual, Chapter 2",
        "url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf"
      },
      {
        "name": "NCTCOG iSWM Technical Manual—Hydrology",
        "url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf"
      },
      {
        "name": "NOAA Atlas 14 Volume 9",
        "url": "https://www.weather.gov/media/owp/hdsc_documents/Atlas14_Volume9.pdf"
      },
      {
        "name": "NOAA Precipitation Frequency Data Server",
        "url": "https://hdsc.nws.noaa.gov/pfds/"
      },
      {
        "name": "NOAA Atlas 15 informational page",
        "url": "https://water.noaa.gov/about/atlas15"
      },
      {
        "name": "City of Huntsville Stormwater Management Manual 2020",
        "url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/"
      },
      {
        "name": "City of Huntsville Ordinance No. 20-1062",
        "url": "https://mcclibraryfunctions.azurewebsites.us/api/ordinanceDownload/12962/1058143/pdf?forceDownload=true"
      }
    ],
    "limitations": [
      "The coefficient comparison is a six-manual sample, not a census of U.S. agencies.",
      "Cross-manual categories are not always identical; the source category remains visible in the records.",
      "Runoff coefficients are design guidance, not measurements made by this study.",
      "Huntsville precipitation values are point/reference estimates and are not uniform across a city or county.",
      "PDS average recurrence interval and annual exceedance probability are different frequency concepts.",
      "Version 1.0.0 includes 90% confidence bounds for the 24-hour Huntsville row only, although the City source figure publishes bounds for all cells.",
      "NOAA Atlas 15 is under development and may change the applicable precipitation-frequency standard after release."
    ],
    "columns": [
      "dataset_version",
      "verification_date",
      "record_type",
      "record_id",
      "geography",
      "jurisdiction",
      "parameter",
      "duration",
      "duration_hours",
      "recurrence_interval_years",
      "annual_exceedance_probability_percent",
      "value",
      "value_min",
      "value_max",
      "lower_90_ci",
      "upper_90_ci",
      "unit",
      "input_area_sq_ft",
      "input_area_acres",
      "input_precipitation_in",
      "input_runoff_coefficient",
      "formula_or_method",
      "source_title",
      "source_page",
      "source_url",
      "verification_tier",
      "publish_status",
      "notes"
    ]
  },
  "records": [
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "exact_unit_conversion",
      "record_id": "conv-gal-per-inch-sqft",
      "geography": "United States customary units",
      "jurisdiction": "",
      "parameter": "Gallons from 1 inch over 1 square foot",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.6233766233766234",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "144 in³ ÷ 231 in³/US gal = 48/77 US gal",
      "source_title": "NIST Handbook 44 (2026), Appendix C",
      "source_page": "C-6 / PDF p. 5",
      "source_url": "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Exact value is 48/77 U.S. gallon per square-foot-inch; the decimal field is a finite representation. Before infiltration, interception, evaporation, storage, or other losses."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "exact_unit_conversion",
      "record_id": "conv-gal-per-acre-inch",
      "geography": "United States customary units",
      "jurisdiction": "",
      "parameter": "Gallons from 1 inch over 1 acre",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "27154.285714285714",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "43,560 × (48/77) = 2,090,880/77 US gal",
      "source_title": "NIST Handbook 44 (2026), Appendix C",
      "source_page": "C-6 / PDF p. 5",
      "source_url": "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Exact value is 2,090,880/77 U.S. gallons, or 3,630 cubic feet; the decimal field is a finite representation. Before losses."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "exact_unit_conversion",
      "record_id": "conv-rational-us-factor",
      "geography": "United States customary units",
      "jurisdiction": "",
      "parameter": "Exact U.S.-unit factor in Rational Method",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "1.0083333333333333",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "cfs per (acre·inch/hour)",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "43,560 ft²/acre ÷ 12 in/ft ÷ 3,600 s/hour = 121/120",
      "source_title": "NIST Handbook 44 (2026), Appendix C",
      "source_page": "C-6 / PDF p. 5",
      "source_url": "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Exact factor is 121/120; the decimal field is a finite representation. Use Q = (121/120) × C × i × A in exact U.S. customary units; Q ≈ C i A is the conventional shortcut."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "0.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "0.468",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "0.582",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "0.682",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "0.826",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "0.942",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "1.06",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "1.19",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "1.37",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-5-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "1.51",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "0.586",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "0.685",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "0.853",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "0.999",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "1.21",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "1.38",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "1.56",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "1.74",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "2.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "2.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "0.715",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "0.835",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "1.04",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "1.22",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "1.48",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "1.68",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "1.9",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "2.13",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "2.44",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-15-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "2.69",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "1.03",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "1.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "1.49",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "1.74",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "2.11",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "2.41",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "2.72",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "3.05",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "3.52",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "3.88",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "1.39",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "1.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "1.97",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "2.28",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "2.74",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "3.11",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "3.5",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "3.91",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "4.48",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "4.93",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "1.75",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "2.01",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "2.44",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "2.82",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "3.37",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "3.82",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "4.28",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "4.77",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "5.45",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-hr-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-hr",
      "duration_hours": "2",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "5.98",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "2.01",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "2.29",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "2.77",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "3.19",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "3.78",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "4.26",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "4.76",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "5.29",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "6.01",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-hr-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-hr",
      "duration_hours": "3",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "6.57",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "2.46",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "2.81",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "3.39",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "3.9",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "4.61",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "5.18",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "5.77",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "6.38",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "7.22",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-6-hr-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "6-hr",
      "duration_hours": "6",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "7.87",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "2.93",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "3.37",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "4.11",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "4.74",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "5.63",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "6.33",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "7.06",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "7.81",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "8.83",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-12-hr-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "12-hr",
      "duration_hours": "12",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "9.62",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "3.45",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "2.9",
      "upper_90_ci": "4.11",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "3.98",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "3.35",
      "upper_90_ci": "4.75",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "4.87",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "4.08",
      "upper_90_ci": "5.83",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "5.63",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "4.68",
      "upper_90_ci": "6.76",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "6.69",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "5.37",
      "upper_90_ci": "8.31",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "7.52",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "5.9",
      "upper_90_ci": "9.49",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "8.37",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "6.32",
      "upper_90_ci": "10.8",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "9.25",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "6.68",
      "upper_90_ci": "12.3",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "10.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "7.23",
      "upper_90_ci": "14.3",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-24-hr-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "11.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "7.65",
      "upper_90_ci": "15.8",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "4.04",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "4.64",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "5.64",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "6.47",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "7.63",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "8.54",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "9.46",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "10.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "11.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-2-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "2-day",
      "duration_hours": "48",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "12.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "4.44",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "5.06",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "6.08",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "6.94",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "8.13",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "9.06",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "10.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "11.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "12.3",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-3-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "3-day",
      "duration_hours": "72",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "13.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "4.78",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "5.42",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "6.46",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "7.33",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "8.54",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "9.49",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "10.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "11.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "12.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-4-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "4-day",
      "duration_hours": "96",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "13.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "5.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "6.37",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "7.48",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "8.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "9.67",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "10.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "11.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "12.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "13.9",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-7-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "7-day",
      "duration_hours": "168",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "14.9",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "6.51",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "7.23",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "8.39",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "9.35",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "10.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "11.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "12.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "13.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "15.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-10-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "10-day",
      "duration_hours": "240",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "16.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "8.88",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "9.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "11.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "12.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "13.5",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "14.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "15.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "16.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "18.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-20-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "20-day",
      "duration_hours": "480",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "18.9",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "11.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "11.9",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "13.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "14.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "16.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "17.3",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "18.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "19.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "20.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-30-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "30-day",
      "duration_hours": "720",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "21.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "13.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "14.9",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "16.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "18.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "19.8",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "21.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "22.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "23.3",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "24.5",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-45-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "45-day",
      "duration_hours": "1080",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "25.3",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "16.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "17.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "19.7",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "21.3",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "23.3",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "24.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "25.8",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "26.8",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "27.9",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "precipitation_frequency_depth",
      "record_id": "hsv-pds-60-day-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "PDS-based point precipitation frequency central estimate",
      "duration": "60-day",
      "duration_hours": "1440",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "28.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Transcribed central estimate from Figure 4-1; 24-hour confidence intervals transcribed separately.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Figure 4-1 (NOAA Atlas 14 PDS table)",
      "source_page": "PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Point/reference data for Huntsville, not a county-wide uniform value. NOAA PFDS should be checked for the exact project location and latest version. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "4.8",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.4",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "5.616",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.468",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "6.984",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.582",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "8.184",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.682",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "9.912",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.826",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "11.304",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.942",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "12.72",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.06",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "14.28",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.19",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "16.44",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.37",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-5-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "5-min",
      "duration_hours": "0.08333333333333333",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "18.12",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.51",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "3.516",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.586",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "4.11",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.685",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "5.118",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.853",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "5.994",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.999",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "7.26",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.21",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "8.28",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.38",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "9.36",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.56",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "10.44",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.74",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "12",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.0",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-10-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "10-min",
      "duration_hours": "0.16666666666666666",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "13.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.2",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "2.86",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.715",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "3.34",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "0.835",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "4.16",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.04",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "4.88",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.22",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "5.92",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.48",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "6.72",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.68",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "7.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.9",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "8.52",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.13",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "9.76",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.44",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-15-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "15-min",
      "duration_hours": "0.25",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "10.76",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.69",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "2.06",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.03",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "2.4",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.2",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "2.98",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.49",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "3.48",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.74",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "4.22",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.11",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "4.82",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.41",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "5.44",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.72",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "6.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "3.05",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "7.04",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "3.52",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-30-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "30-min",
      "duration_hours": "0.5",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "7.76",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "3.88",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-1y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "1",
      "annual_exceedance_probability_percent": "",
      "value": "1.39",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.39",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-2y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "1.6",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.6",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-5y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "5",
      "annual_exceedance_probability_percent": "",
      "value": "1.97",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "1.97",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-10y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "2.28",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.28",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-25y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "2.74",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "2.74",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-50y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "3.11",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "3.11",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-100y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "3.5",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "3.5",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-200y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "200",
      "annual_exceedance_probability_percent": "",
      "value": "3.91",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "3.91",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-500y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "500",
      "annual_exceedance_probability_percent": "",
      "value": "4.48",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "4.48",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "derived_average_intensity",
      "record_id": "hsv-intensity-60-min-1000y",
      "geography": "Huntsville, Alabama reference data",
      "jurisdiction": "City of Huntsville, primarily Madison County, Alabama",
      "parameter": "Average precipitation intensity over selected duration",
      "duration": "60-min",
      "duration_hours": "1",
      "recurrence_interval_years": "1000",
      "annual_exceedance_probability_percent": "",
      "value": "4.93",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches/hour",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "4.93",
      "input_runoff_coefficient": "",
      "formula_or_method": "Central precipitation depth ÷ duration in hours",
      "source_title": "Derived by Huntsville Yard Drainage Research from City of Huntsville Figure 4-1",
      "source_page": "Manual PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Average intensity across the listed duration; not an instantaneous observed rate. NOAA labels these PDS values by average recurrence interval; the inverse of PDS ARI is not annual exceedance probability."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-01-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Woodlands (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.1",
      "value_max": "0.15",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-01-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Woodlands (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.15",
      "value_max": "0.2",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-02-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pasture, grass, and farmland (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.15",
      "value_max": "0.2",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%. Assumes good ground cover and conservation treatment."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-02-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pasture, grass, and farmland (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.2",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%. Assumes good ground cover and conservation treatment."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-03-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Rooftops and pavement (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-03-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Rooftops and pavement (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-04-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pervious pavement (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.75",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%. Depends on depth and permeability of underlying strata."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-04-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pervious pavement (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%. Depends on depth and permeability of underlying strata."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-05-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: 1/2-acre lots and larger (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.3",
      "value_max": "0.35",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-05-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: 1/2-acre lots and larger (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.35",
      "value_max": "0.45",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-06-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: smaller lots (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.35",
      "value_max": "0.45",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-06-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: smaller lots (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.4",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-07-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Duplexes (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.35",
      "value_max": "0.45",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-07-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Duplexes (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.4",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-08-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Multifamily: apartments, townhouses, condominiums (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.45",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-08-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Multifamily: apartments, townhouses, condominiums (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.5",
      "value_max": "0.7",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-09-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Commercial and industrial (Flat slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.5",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-09-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Commercial and industrial (Flat slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.5",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 0–2%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-10-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Woodlands (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.15",
      "value_max": "0.2",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-10-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Woodlands (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.2",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-11-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pasture, grass, and farmland (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.2",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%. Assumes good ground cover and conservation treatment."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-11-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pasture, grass, and farmland (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.25",
      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%. Assumes good ground cover and conservation treatment."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-12-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Rooftops and pavement (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-12-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Rooftops and pavement (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-13-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pervious pavement (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.8",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%. Depends on depth and permeability of underlying strata."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-13-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pervious pavement (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.9",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
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      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%. Depends on depth and permeability of underlying strata."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-14-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: 1/2-acre lots and larger (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.35",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-14-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: 1/2-acre lots and larger (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.4",
      "value_max": "0.55",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-15-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: smaller lots (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.4",
      "value_max": "0.55",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-15-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: smaller lots (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.45",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-16-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Duplexes (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.4",
      "value_max": "0.55",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-16-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Duplexes (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.45",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-17-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Multifamily: apartments, townhouses, condominiums (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.5",
      "value_max": "0.7",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-17-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Multifamily: apartments, townhouses, condominiums (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.6",
      "value_max": "0.8",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-18-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Commercial and industrial (Rolling slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.5",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-18-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Commercial and industrial (Rolling slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.6",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 2–7%."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-19-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Woodlands (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.2",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-19-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Woodlands (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.25",
      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-20-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pasture, grass, and farmland (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.25",
      "value_max": "0.35",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+. Assumes good ground cover and conservation treatment."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-20-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pasture, grass, and farmland (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.3",
      "value_max": "0.4",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+. Assumes good ground cover and conservation treatment."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-21-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Rooftops and pavement (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-21-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Rooftops and pavement (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-22-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pervious pavement (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.85",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+. Depends on depth and permeability of underlying strata."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-22-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Pervious pavement (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.9",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+. Depends on depth and permeability of underlying strata."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-23-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: 1/2-acre lots and larger (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.4",
      "value_max": "0.55",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-23-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: 1/2-acre lots and larger (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.5",
      "value_max": "0.65",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-24-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: smaller lots (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.45",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-24-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Single-family residential: smaller lots (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.55",
      "value_max": "0.7",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-25-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Duplexes (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.45",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-25-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Duplexes (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.55",
      "value_max": "0.7",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-26-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Multifamily: apartments, townhouses, condominiums (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.6",
      "value_max": "0.75",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-26-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Multifamily: apartments, townhouses, condominiums (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.65",
      "value_max": "0.85",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-27-sandy",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Commercial and industrial (Steep slope; sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.6",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "hsv-c-27-clay",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Rational Method runoff coefficient: Commercial and industrial (Steep slope; clay soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.65",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "City table applies to design-storm return periods of 10 years or less.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-2",
      "source_page": "PDF p. 105",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Slope 7%+."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "hsv-frequency-factor-2to10y",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Runoff coefficient frequency factor for 2–10-year return period",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "2–10",
      "annual_exceedance_probability_percent": "",
      "value": "1.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "C_T = C_10 × X_T; C_T must not exceed 1.0.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-3 and Equation 4-5",
      "source_page": "PDF pp. 74–75 and 106",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The base coefficient table applies to design storms of 10 years or less."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "hsv-frequency-factor-25y",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Runoff coefficient frequency factor for 25-year return period",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "1.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "C_T = C_10 × X_T; C_T must not exceed 1.0.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-3 and Equation 4-5",
      "source_page": "PDF pp. 74–75 and 106",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The base coefficient table applies to design storms of 10 years or less."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "hsv-frequency-factor-50y",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Runoff coefficient frequency factor for 50-year return period",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "1.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "C_T = C_10 × X_T; C_T must not exceed 1.0.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-3 and Equation 4-5",
      "source_page": "PDF pp. 74–75 and 106",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The base coefficient table applies to design storms of 10 years or less."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "hsv-frequency-factor-100y",
      "geography": "Huntsville, Alabama design criteria",
      "jurisdiction": "City of Huntsville",
      "parameter": "Runoff coefficient frequency factor for 100-year return period",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "1.25",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "C_T = C_10 × X_T; C_T must not exceed 1.0.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020, Table 4-3 and Equation 4-5",
      "source_page": "PDF pp. 74–75 and 106",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The base coefficient table applies to design storms of 10 years or less."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-1000-one-inch-event",
      "geography": "Universal reference scenario",
      "jurisdiction": "",
      "parameter": "Gross rainfall volume: 1,000 ft², one-inch reference event",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "623.376623376623",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "1000",
      "input_area_acres": "0.02295684113865932",
      "input_precipitation_in": "1.0",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 (2026), Appendix C",
      "source_page": "NIST Appendix C, C-6 / PDF p. 5",
      "source_url": "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Exact conversion is 48/77 U.S. gallon per square-foot-inch."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-1000-hsv-2y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 1,000 ft², Huntsville 2-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "2481.038961038961",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "1000",
      "input_area_acres": "0.02295684113865932",
      "input_precipitation_in": "3.98",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-1000-hsv-10y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 1,000 ft², Huntsville 10-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "3509.61038961039",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "1000",
      "input_area_acres": "0.02295684113865932",
      "input_precipitation_in": "5.63",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-1000-hsv-25y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 1,000 ft², Huntsville 25-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "4170.38961038961",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "1000",
      "input_area_acres": "0.02295684113865932",
      "input_precipitation_in": "6.69",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-1000-hsv-100y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 1,000 ft², Huntsville 100-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "5217.662337662338",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "1000",
      "input_area_acres": "0.02295684113865932",
      "input_precipitation_in": "8.37",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-2000-one-inch-event",
      "geography": "Universal reference scenario",
      "jurisdiction": "",
      "parameter": "Gross rainfall volume: 2,000 ft², one-inch reference event",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "1246.753246753247",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "2000",
      "input_area_acres": "0.04591368227731864",
      "input_precipitation_in": "1.0",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 (2026), Appendix C",
      "source_page": "NIST Appendix C, C-6 / PDF p. 5",
      "source_url": "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Exact conversion is 48/77 U.S. gallon per square-foot-inch."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-2000-hsv-2y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 2,000 ft², Huntsville 2-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "4962.077922077922",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "2000",
      "input_area_acres": "0.04591368227731864",
      "input_precipitation_in": "3.98",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-2000-hsv-10y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 2,000 ft², Huntsville 10-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "7019.220779220779",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "2000",
      "input_area_acres": "0.04591368227731864",
      "input_precipitation_in": "5.63",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-2000-hsv-25y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 2,000 ft², Huntsville 25-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "8340.779220779221",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "2000",
      "input_area_acres": "0.04591368227731864",
      "input_precipitation_in": "6.69",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-2000-hsv-100y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 2,000 ft², Huntsville 100-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "10435.324675324675",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "2000",
      "input_area_acres": "0.04591368227731864",
      "input_precipitation_in": "8.37",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-5000-one-inch-event",
      "geography": "Universal reference scenario",
      "jurisdiction": "",
      "parameter": "Gross rainfall volume: 5,000 ft², one-inch reference event",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "3116.883116883117",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "5000",
      "input_area_acres": "0.1147842056932966",
      "input_precipitation_in": "1.0",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 (2026), Appendix C",
      "source_page": "NIST Appendix C, C-6 / PDF p. 5",
      "source_url": "https://www.nist.gov/document/2026-nist-handbook-44-appendix-c",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Exact conversion is 48/77 U.S. gallon per square-foot-inch."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-5000-hsv-2y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 5,000 ft², Huntsville 2-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "2",
      "annual_exceedance_probability_percent": "",
      "value": "12405.194805194805",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "5000",
      "input_area_acres": "0.1147842056932966",
      "input_precipitation_in": "3.98",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-5000-hsv-10y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 5,000 ft², Huntsville 10-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "10",
      "annual_exceedance_probability_percent": "",
      "value": "17548.051948051948",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "5000",
      "input_area_acres": "0.1147842056932966",
      "input_precipitation_in": "5.63",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-5000-hsv-25y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 5,000 ft², Huntsville 25-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "20851.948051948052",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "5000",
      "input_area_acres": "0.1147842056932966",
      "input_precipitation_in": "6.69",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "gross_rainfall_scenario",
      "record_id": "gross-rainfall-5000-hsv-100y-24h",
      "geography": "Huntsville, Alabama reference scenario",
      "jurisdiction": "City of Huntsville",
      "parameter": "Gross rainfall volume: 5,000 ft², Huntsville 100-year-ARI, 24-hour central estimate",
      "duration": "24-hr",
      "duration_hours": "24",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "26088.311688311688",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "US gallons",
      "input_area_sq_ft": "5000",
      "input_area_acres": "0.1147842056932966",
      "input_precipitation_in": "8.37",
      "input_runoff_coefficient": "",
      "formula_or_method": "V_gross_gal = P_in × A_ft² × (48/77)",
      "source_title": "Derived by Huntsville Yard Drainage Research from NIST Handbook 44 and City of Huntsville Figure 4-1",
      "source_page": "NIST Appendix C, C-6; City manual Figure 4-1, PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "◆",
      "publish_status": "Publishable as derived",
      "notes": "Gross rainfall volume only; no runoff, loss, collection, or Rational Method coefficient applied. Precipitation depth is the City manual Figure 4-1 central estimate; exact volume conversion is 48/77. Frequency label is PDS average recurrence interval; reciprocal AEP is intentionally blank."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "source_reconciliation",
      "record_id": "reconcile-2-year-24h",
      "geography": "Huntsville, Alabama",
      "jurisdiction": "City of Huntsville",
      "parameter": "Worked-example depth versus Figure 4-1: 2-year, 24-hour",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Figure 4-1 central estimate minus worked-example value",
      "source_title": "City of Huntsville Stormwater Management Manual 2020",
      "source_page": "PDF p. 82 versus PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable with context",
      "notes": "Worked example states 3.78 in; Figure 4-1 states 3.98 in. The calculator uses the Figure 4-1 table and disclose the conflict."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "source_reconciliation",
      "record_id": "reconcile-25-year-24h",
      "geography": "Huntsville, Alabama",
      "jurisdiction": "City of Huntsville",
      "parameter": "Worked-example depth versus Figure 4-1: 25-year, 24-hour",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.48",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "inches",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Figure 4-1 central estimate minus worked-example value",
      "source_title": "City of Huntsville Stormwater Management Manual 2020",
      "source_page": "PDF p. 77 versus PDF p. 118",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable with context",
      "notes": "Worked example states 6.21 in; Figure 4-1 states 6.69 in. The calculator uses the Figure 4-1 table and disclose the conflict."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "fhwa-c-business-downtown-areas",
      "geography": "United States federal guidance",
      "jurisdiction": "Federal Highway Administration",
      "parameter": "Rational Method runoff coefficient: Business—downtown areas",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.7",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Federal Highway Administration, Urban Drainage Design, HEC-22, 4th ed. (FHWA-HIF-24-006)",
      "source_page": "Table 4.1, report PDF p. 58 / printed p. 26",
      "source_url": "https://www.fhwa.dot.gov/engineering/hydraulics/pubs/hif24006.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table caption credits ASCE (1960)."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "fhwa-c-business-neighborhood-areas",
      "geography": "United States federal guidance",
      "jurisdiction": "Federal Highway Administration",
      "parameter": "Rational Method runoff coefficient: Business—neighborhood areas",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.5",
      "value_max": "0.7",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Federal Highway Administration, Urban Drainage Design, HEC-22, 4th ed. (FHWA-HIF-24-006)",
      "source_page": "Table 4.1, report PDF p. 58 / printed p. 26",
      "source_url": "https://www.fhwa.dot.gov/engineering/hydraulics/pubs/hif24006.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table caption credits ASCE (1960)."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "fhwa-c-residential-single-family-areas",
      "geography": "United States federal guidance",
      "jurisdiction": "Federal Highway Administration",
      "parameter": "Rational Method runoff coefficient: Residential—single-family areas",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.3",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Federal Highway Administration, Urban Drainage Design, HEC-22, 4th ed. (FHWA-HIF-24-006)",
      "source_page": "Table 4.1, report PDF p. 58 / printed p. 26",
      "source_url": "https://www.fhwa.dot.gov/engineering/hydraulics/pubs/hif24006.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table caption credits ASCE (1960)."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "fhwa-c-residential-multi-units-detached",
      "geography": "United States federal guidance",
      "jurisdiction": "Federal Highway Administration",
      "parameter": "Rational Method runoff coefficient: Residential—multi-units, detached",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.4",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Federal Highway Administration, Urban Drainage Design, HEC-22, 4th ed. (FHWA-HIF-24-006)",
      "source_page": "Table 4.1, report PDF p. 58 / printed p. 26",
      "source_url": "https://www.fhwa.dot.gov/engineering/hydraulics/pubs/hif24006.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table caption credits ASCE (1960)."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "fhwa-c-residential-multi-units-attached",
      "geography": "United States federal guidance",
      "jurisdiction": "Federal Highway Administration",
      "parameter": "Rational Method runoff coefficient: Residential—multi-units, attached",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.6",
      "value_max": "0.75",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Federal Highway Administration, Urban Drainage Design, HEC-22, 4th ed. (FHWA-HIF-24-006)",
      "source_page": "Table 4.1, report PDF p. 58 / printed p. 26",
      "source_url": "https://www.fhwa.dot.gov/engineering/hydraulics/pubs/hif24006.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table caption credits ASCE (1960)."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "fhwa-c-residential-suburban",
      "geography": "United States federal guidance",
      "jurisdiction": "Federal Highway Administration",
      "parameter": "Rational Method runoff coefficient: Residential—suburban",
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      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Business—downtown areas",
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      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "upper_90_ci": "",
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      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Business—neighborhood areas",
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      "annual_exceedance_probability_percent": "",
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      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
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      "jurisdiction": "Texas Department of Transportation",
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      "annual_exceedance_probability_percent": "",
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      "record_id": "txdot-c-residential-multi-units-detached",
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      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Residential—multi-units, detached",
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      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "unit": "dimensionless",
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      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
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    {
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      "record_type": "runoff_coefficient_range",
      "record_id": "txdot-c-residential-multi-units-attached",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Residential—multi-units, attached",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "unit": "dimensionless",
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      "input_area_acres": "",
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      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 4-10",
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      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "txdot-c-residential-suburban",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Residential—suburban",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "0.35",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
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      "input_area_acres": "",
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      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
    },
    {
      "dataset_version": "1.0.0",
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      "record_id": "txdot-c-apartment-dwelling-areas",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Apartment dwelling areas",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
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      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Texas Department of Transportation Hydraulic Design Manual, Chapter 4, Section 12",
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      "source_url": "https://www.txdot.gov/manuals/des/hyd/chapter-4--hydrology/section-12--rational-method.html",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
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    {
      "dataset_version": "1.0.0",
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      "record_type": "runoff_coefficient_range",
      "record_id": "txdot-c-industrial-light-areas",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Industrial—light areas",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "unit": "dimensionless",
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      "input_area_acres": "",
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      "verification_tier": "★",
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      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
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    {
      "dataset_version": "1.0.0",
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      "record_type": "runoff_coefficient_range",
      "record_id": "txdot-c-industrial-heavy-areas",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Industrial—heavy areas",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
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      "unit": "dimensionless",
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      "input_area_acres": "",
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      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
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    {
      "dataset_version": "1.0.0",
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      "record_type": "runoff_coefficient_range",
      "record_id": "txdot-c-parks-and-cemeteries",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Parks and cemeteries",
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      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
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      "unit": "dimensionless",
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      "input_area_acres": "",
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      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
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    {
      "dataset_version": "1.0.0",
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      "record_type": "runoff_coefficient_range",
      "record_id": "txdot-c-playgrounds",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Playgrounds",
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      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "parameter": "Rational Method runoff coefficient: Railroad yards",
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      "annual_exceedance_probability_percent": "",
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      "record_type": "runoff_coefficient_range",
      "record_id": "txdot-c-deep-sand-area",
      "geography": "Texas",
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      "parameter": "Rational Method runoff coefficient: Deep sand area",
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      "annual_exceedance_probability_percent": "",
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      "verification_tier": "★",
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      "notes": "TxDOT describes Table 4-10 as typical of design guides in civil-engineering hydrology texts."
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    {
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      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "txdot-c-steep-grassed-slopes",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Steep grassed slopes",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
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      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
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      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-gravel-pavement-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Gravel pavement (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.55",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-gravel-pavement-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Gravel pavement (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-city-business-areas-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: City business areas (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.8",
      "value_max": "0.8",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-city-business-areas-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: City business areas (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.85",
      "value_max": "0.85",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-city-business-areas-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: City business areas (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.85",
      "value_max": "0.85",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-suburban-residential-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Suburban residential (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.25",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-suburban-residential-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Suburban residential (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.35",
      "value_min": "0.35",
      "value_max": "0.35",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-suburban-residential-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Suburban residential (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.4",
      "value_min": "0.4",
      "value_max": "0.4",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-single-family-residential-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Single-family residential (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.3",
      "value_min": "0.3",
      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-single-family-residential-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Single-family residential (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.4",
      "value_min": "0.4",
      "value_max": "0.4",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-single-family-residential-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Single-family residential (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.5",
      "value_min": "0.5",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-multi-units-detached-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Multi-units—detached (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.4",
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      "value_max": "0.4",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-multi-units-detached-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Multi-units—detached (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.5",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-multi-units-detached-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Multi-units—detached (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.6",
      "value_min": "0.6",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-multi-units-attached-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Multi-units—attached (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.6",
      "value_min": "0.6",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-multi-units-attached-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Multi-units—attached (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.65",
      "value_min": "0.65",
      "value_max": "0.65",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-multi-units-attached-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Multi-units—attached (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.7",
      "value_min": "0.7",
      "value_max": "0.7",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-lawns-very-sandy-soil-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Lawns—very sandy soil (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.05",
      "value_min": "0.05",
      "value_max": "0.05",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
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      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
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      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-lawns-very-sandy-soil-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Lawns—very sandy soil (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.1",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-lawns-sandy-soil-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Lawns—sandy soil (Flat, under 2%)",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-lawns-sandy-soil-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Lawns—sandy soil (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-lawns-sandy-soil-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Lawns—sandy soil (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-lawns-heavy-soil-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Lawns—heavy soil (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.17",
      "value_max": "0.17",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-lawns-heavy-soil-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Lawns—heavy soil (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.22",
      "value_max": "0.22",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-lawns-heavy-soil-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Lawns—heavy soil (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.35",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-grass-shoulders-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Grass shoulders (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.25",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-grass-shoulders-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Grass shoulders (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.25",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Grass shoulders (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-side-slopes-earth-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Side slopes—earth (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-side-slopes-earth-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Side slopes—earth (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
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      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Side slopes—earth (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
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      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "jurisdiction": "Washington State Department of Transportation",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
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      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
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      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
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      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
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      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
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      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
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      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "jurisdiction": "Washington State Department of Transportation",
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      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-median-areas-turf-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Median areas—turf (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.25",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
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      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-median-areas-turf-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Median areas—turf (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-median-areas-turf-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Median areas—turf (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-cultivated-land-clay-and-loam-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Cultivated land—clay and loam (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.5",
      "value_min": "0.5",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-cultivated-land-clay-and-loam-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Cultivated land—clay and loam (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.55",
      "value_max": "0.55",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-cultivated-land-clay-and-loam-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Cultivated land—clay and loam (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-cultivated-land-sand-and-gravel-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Cultivated land—sand and gravel (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.25",
      "value_min": "0.25",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-cultivated-land-sand-and-gravel-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Cultivated land—sand and gravel (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.3",
      "value_min": "0.3",
      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-cultivated-land-sand-and-gravel-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Cultivated land—sand and gravel (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.35",
      "value_max": "0.35",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-industrial-areas-light-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Industrial areas—light (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.5",
      "value_min": "0.5",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-industrial-areas-light-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Industrial areas—light (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.7",
      "value_min": "0.7",
      "value_max": "0.7",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-industrial-areas-light-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Industrial areas—light (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.8",
      "value_min": "0.8",
      "value_max": "0.8",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-industrial-areas-heavy-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Industrial areas—heavy (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.6",
      "value_min": "0.6",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-industrial-areas-heavy-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Industrial areas—heavy (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.8",
      "value_min": "0.8",
      "value_max": "0.8",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-industrial-areas-heavy-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Industrial areas—heavy (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.9",
      "value_min": "0.9",
      "value_max": "0.9",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-parks-and-cemeteries-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Parks and cemeteries (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.1",
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      "value_max": "0.1",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-parks-and-cemeteries-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Parks and cemeteries (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.15",
      "value_min": "0.15",
      "value_max": "0.15",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-parks-and-cemeteries-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Parks and cemeteries (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.25",
      "value_min": "0.25",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-playgrounds-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Playgrounds (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.2",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-playgrounds-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Playgrounds (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.25",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-playgrounds-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Playgrounds (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-woodland-and-forests-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Woodland and forests (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.1",
      "value_max": "0.1",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-woodland-and-forests-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Woodland and forests (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.15",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-woodland-and-forests-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Woodland and forests (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.2",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-meadows-and-pasture-land-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Meadows and pasture land (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "0.25",
      "value_max": "0.25",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-meadows-and-pasture-land-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Meadows and pasture land (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.3",
      "value_min": "0.3",
      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-meadows-and-pasture-land-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Meadows and pasture land (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.35",
      "value_min": "0.35",
      "value_max": "0.35",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-pasture-with-frozen-ground-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Pasture with frozen ground (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.4",
      "value_min": "0.4",
      "value_max": "0.4",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-pasture-with-frozen-ground-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Pasture with frozen ground (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.45",
      "value_min": "0.45",
      "value_max": "0.45",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-pasture-with-frozen-ground-hilly-over-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Pasture with frozen ground (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.5",
      "value_min": "0.5",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-unimproved-areas-flat-under-2",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Unimproved areas (Flat, under 2%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.1",
      "value_min": "0.1",
      "value_max": "0.1",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "wsdot-c-unimproved-areas-rolling-2-10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Unimproved areas (Rolling, 2–10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.2",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
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      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Rational Method runoff coefficient: Unimproved areas (Hilly, over 10%)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 2-2 applies to the 10-year return frequency."
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    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-lawn-flat-2-or-less-sandy-soil",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Lawn (Flat, 2% or less) (Sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
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      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Lawn (Average, 2–7%) (Sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_max": "0.15",
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      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-lawn-steep-over-7-sandy-soil",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Lawn (Steep, over 7%) (Sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.2",
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      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
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      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
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      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-asphalt-and-concrete-streets",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Asphalt and concrete streets",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.95",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-brick-streets",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Brick streets",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.85",
      "value_min": "0.85",
      "value_max": "0.85",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-drives-walks-and-roofs",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Drives, walks, and roofs",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.95",
      "value_min": "0.95",
      "value_max": "0.95",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-gravel-areas",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Gravel areas",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.5",
      "value_min": "0.5",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-graded-or-no-plant-cover-0-5-sandy-soil",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Graded or no plant cover (0–5%) (Sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.3",
      "value_min": "0.3",
      "value_max": "0.3",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-graded-or-no-plant-cover-5-10-sandy-soil",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Graded or no plant cover (5–10%) (Sandy soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.4",
      "value_min": "0.4",
      "value_max": "0.4",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-graded-or-no-plant-cover-0-5-clayey-soil",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Graded or no plant cover (0–5%) (Clayey soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.5",
      "value_min": "0.5",
      "value_max": "0.5",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_range",
      "record_id": "nctcog-c-graded-or-no-plant-cover-5-10-clayey-soil",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Rational Method runoff coefficient: Graded or no plant cover (5–10%) (Clayey soil)",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "0.6",
      "value_min": "0.6",
      "value_max": "0.6",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct transcription of the issuing agency’s published Rational Method coefficient.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": ""
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "odot-frequency-factor-le10",
      "geography": "Oregon",
      "jurisdiction": "Oregon Department of Transportation",
      "parameter": "Runoff-coefficient frequency factor: 10 years or less",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "≤10",
      "annual_exceedance_probability_percent": "",
      "value": "1.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "Oregon Department of Transportation Hydraulics Manual, Hydrology Appendix F",
      "source_page": "Table 2, April 2014",
      "source_url": "https://www.oregon.gov/odot/hydraulics/Docs_Hydraulics_Manual/Hydraulics-07-F.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual writes Q = Cf C i A."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "odot-frequency-factor-25",
      "geography": "Oregon",
      "jurisdiction": "Oregon Department of Transportation",
      "parameter": "Runoff-coefficient frequency factor: 25 years",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "1.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "Oregon Department of Transportation Hydraulics Manual, Hydrology Appendix F",
      "source_page": "Table 2, April 2014",
      "source_url": "https://www.oregon.gov/odot/hydraulics/Docs_Hydraulics_Manual/Hydraulics-07-F.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual writes Q = Cf C i A."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "odot-frequency-factor-50",
      "geography": "Oregon",
      "jurisdiction": "Oregon Department of Transportation",
      "parameter": "Runoff-coefficient frequency factor: 50 years",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "1.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "Oregon Department of Transportation Hydraulics Manual, Hydrology Appendix F",
      "source_page": "Table 2, April 2014",
      "source_url": "https://www.oregon.gov/odot/hydraulics/Docs_Hydraulics_Manual/Hydraulics-07-F.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual writes Q = Cf C i A."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "odot-frequency-factor-100",
      "geography": "Oregon",
      "jurisdiction": "Oregon Department of Transportation",
      "parameter": "Runoff-coefficient frequency factor: 100 years",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "1.25",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "Oregon Department of Transportation Hydraulics Manual, Hydrology Appendix F",
      "source_page": "Table 2, April 2014",
      "source_url": "https://www.oregon.gov/odot/hydraulics/Docs_Hydraulics_Manual/Hydraulics-07-F.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual writes Q = Cf C i A."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "wsdot-frequency-factor-le10",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Runoff-coefficient frequency factor: 10 years or less",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "≤10",
      "annual_exceedance_probability_percent": "",
      "value": "1.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Chapter 2, Section 2-6.2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual states equivalent percentage increases and caps C at 0.95 unless the Region Hydraulics Engineer approves a higher value."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "wsdot-frequency-factor-25",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Runoff-coefficient frequency factor: 25 years",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "1.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Chapter 2, Section 2-6.2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual states equivalent percentage increases and caps C at 0.95 unless the Region Hydraulics Engineer approves a higher value."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "wsdot-frequency-factor-50",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Runoff-coefficient frequency factor: 50 years",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "50",
      "annual_exceedance_probability_percent": "",
      "value": "1.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Chapter 2, Section 2-6.2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual states equivalent percentage increases and caps C at 0.95 unless the Region Hydraulics Engineer approves a higher value."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "wsdot-frequency-factor-100",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Runoff-coefficient frequency factor: 100 years",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "1.25",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Chapter 2, Section 2-6.2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual states equivalent percentage increases and caps C at 0.95 unless the Region Hydraulics Engineer approves a higher value."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "nctcog-frequency-factor-le10",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Runoff-coefficient frequency factor: 10 years or less",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "≤10",
      "annual_exceedance_probability_percent": "",
      "value": "1.0",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.4, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual states that Cf × C must not exceed 1.0."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "nctcog-frequency-factor-25",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Runoff-coefficient frequency factor: 25 years",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "25",
      "annual_exceedance_probability_percent": "",
      "value": "1.1",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.4, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual states that Cf × C must not exceed 1.0."
    },
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      "duration_hours": "",
      "recurrence_interval_years": "50",
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      "value": "1.2",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.4, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual states that Cf × C must not exceed 1.0."
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    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "runoff_coefficient_frequency_factor",
      "record_id": "nctcog-frequency-factor-100",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
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      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "100",
      "annual_exceedance_probability_percent": "",
      "value": "1.25",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "dimensionless",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Apply the published factor or equivalent percentage increase to the base coefficient for the stated recurrence interval.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.4, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The manual states that Cf × C must not exceed 1.0."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "source_provenance",
      "record_id": "fhwa-coefficient-table-provenance",
      "geography": "United States federal guidance",
      "jurisdiction": "Federal Highway Administration",
      "parameter": "Published provenance of the runoff-coefficient table",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
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      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "text",
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      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct reading of the table caption and adjacent source notes.",
      "source_title": "Federal Highway Administration, Urban Drainage Design, HEC-22, 4th ed. (FHWA-HIF-24-006)",
      "source_page": "Table 4.1, report PDF p. 58 / printed p. 26",
      "source_url": "https://www.fhwa.dot.gov/engineering/hydraulics/pubs/hif24006.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 4.1 caption credits ASCE (1960), Design Manual for Storm Drainage."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "source_provenance",
      "record_id": "txdot-coefficient-table-provenance",
      "geography": "Texas",
      "jurisdiction": "Texas Department of Transportation",
      "parameter": "Published provenance of the runoff-coefficient table",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "text",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct reading of the table caption and adjacent source notes.",
      "source_title": "Texas Department of Transportation Hydraulic Design Manual, Chapter 4, Section 12",
      "source_page": "Table 4-10",
      "source_url": "https://www.txdot.gov/manuals/des/hyd/chapter-4--hydrology/section-12--rational-method.html",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 4-10 is described as typical of design guides found in civil-engineering hydrology texts; the table does not name a single originating publication."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "source_provenance",
      "record_id": "odot-coefficient-table-provenance",
      "geography": "Oregon",
      "jurisdiction": "Oregon Department of Transportation",
      "parameter": "Published provenance of the runoff-coefficient table",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "text",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct reading of the table caption and adjacent source notes.",
      "source_title": "Oregon Department of Transportation Hydraulics Manual, Hydrology Appendix F",
      "source_page": "Table 1, April 2014",
      "source_url": "https://www.oregon.gov/odot/hydraulics/Docs_Hydraulics_Manual/Hydraulics-07-F.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Appendix F Table 1 does not list an originating source in its table title or adjacent notes."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "source_provenance",
      "record_id": "wsdot-coefficient-table-provenance",
      "geography": "Washington",
      "jurisdiction": "Washington State Department of Transportation",
      "parameter": "Published provenance of the runoff-coefficient table",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "text",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct reading of the table caption and adjacent source notes.",
      "source_title": "Washington State Department of Transportation Hydraulics Manual M 23-03.12, Chapter 2",
      "source_page": "Table 2-2, April 2026",
      "source_url": "https://wsdot.wa.gov/publications/manuals/fulltext/m23-03/chapter2.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Chapter 2 Table 2-2 does not list an originating source in its table title or adjacent notes."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "source_provenance",
      "record_id": "nctcog-coefficient-table-provenance",
      "geography": "North Central Texas",
      "jurisdiction": "North Central Texas Council of Governments",
      "parameter": "Published provenance of the runoff-coefficient table",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "text",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct reading of the table caption and adjacent source notes.",
      "source_title": "North Central Texas Council of Governments iSWM Technical Manual—Hydrology",
      "source_page": "Table 1.6, April 2010, revised September 2014",
      "source_url": "https://iswm.nctcog.org/Documents/technical_manual/Hydrology_4-2020.pdf",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 1.6 does not name an originating source; the frequency-factor discussion cites Wright-McLaughlin Engineers (1969)."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "source_provenance",
      "record_id": "huntsville-coefficient-table-provenance",
      "geography": "Huntsville, Alabama",
      "jurisdiction": "City of Huntsville",
      "parameter": "Published provenance of Tables 4-2 and 4-3",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "text",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct reading of the source lines printed below the tables.",
      "source_title": "City of Huntsville Stormwater Management Manual 2020",
      "source_page": "PDF pp. 105–106",
      "source_url": "https://www.huntsvilleal.gov/development/building-construction/permits-standards-a-to-z/stormwater-management-manual-2020/",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "Table 4-2 cites DeKalb County, Georgia (1976). Table 4-3 cites Wright-McLaughlin Engineers (1969)."
    },
    {
      "dataset_version": "1.0.0",
      "verification_date": "2026-07-25",
      "record_type": "regulatory_adoption",
      "record_id": "huntsville-2020-manual-adoption",
      "geography": "Huntsville, Alabama",
      "jurisdiction": "City of Huntsville",
      "parameter": "Adoption and incorporation of the City of Huntsville Stormwater Management Manual, 2020 Edition",
      "duration": "",
      "duration_hours": "",
      "recurrence_interval_years": "",
      "annual_exceedance_probability_percent": "",
      "value": "",
      "value_min": "",
      "value_max": "",
      "lower_90_ci": "",
      "upper_90_ci": "",
      "unit": "text",
      "input_area_sq_ft": "",
      "input_area_acres": "",
      "input_precipitation_in": "",
      "input_runoff_coefficient": "",
      "formula_or_method": "Direct reading of Ordinance No. 20-1062.",
      "source_title": "City of Huntsville Ordinance No. 20-1062",
      "source_page": "Section 1, Sec. 12-331(a)",
      "source_url": "https://mcclibraryfunctions.azurewebsites.us/api/ordinanceDownload/12962/1058143/pdf?forceDownload=true",
      "verification_tier": "★",
      "publish_status": "Publishable",
      "notes": "The ordinance states that the 2020 Edition is referenced and adopted in section 12-1 and incorporated into Article VI by reference."
    }
  ]
}