{
  "version": 1,
  "title": "U.S. Stormwater Practice Synthesis — Research Outline",
  "generated_at": "2026-08-11T01:22:32.319Z",
  "model": "heuristic",
  "sections": [
    {
      "id": "intro",
      "title": "Purpose, Scope, and How to Use This Synthesis",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.56,
      "topic_tags": [
        "general"
      ],
      "source_manual_count": 167,
      "regional_notes": [],
      "summary": "Frames this work as a synthesis of U.S. practice for research and committee review, not adopted regulation or a design manual."
    },
    {
      "id": "applicability",
      "title": "Applicability and Relationship to Permits and Local Codes",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.39,
      "topic_tags": [
        "general"
      ],
      "source_manual_count": 116,
      "regional_notes": [
        "ms4_vs_non_ms4"
      ],
      "summary": "When criteria apply (new development, redevelopment, thresholds) and how state/local manuals interact."
    },
    {
      "id": "hydrology",
      "title": "Hydrology and Design Storms",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.49,
      "topic_tags": [
        "hydrology"
      ],
      "source_manual_count": 295,
      "regional_notes": [
        "arid_west",
        "coastal",
        "cold_climate"
      ],
      "summary": "Return periods and storm definitions used for water quality, channel protection, and flood control."
    },
    {
      "id": "hydrology.design-storms",
      "title": "Design Storm Selection by Purpose",
      "level": 2,
      "parent_id": "hydrology",
      "prevalence": 0.49,
      "topic_tags": [
        "hydrology"
      ],
      "source_manual_count": 295,
      "regional_notes": [
        "arid_west",
        "humid_east"
      ],
      "summary": "Separate WQ, channel, detention, and flood storms; avoid collapsing all purposes into one number."
    },
    {
      "id": "hydrology.methods",
      "title": "Runoff and Peak-Flow Calculation Methods",
      "level": 2,
      "parent_id": "hydrology",
      "prevalence": 0.46,
      "topic_tags": [
        "hydrology",
        "peak_flow"
      ],
      "source_manual_count": 274,
      "regional_notes": [],
      "summary": "Rational Method, NRCS/TR-55, continuous simulation, and when each is required or allowed."
    },
    {
      "id": "hydrology.software",
      "title": "Approved Hydrologic and Hydraulic Software",
      "level": 2,
      "parent_id": "hydrology",
      "prevalence": 0.32,
      "topic_tags": [
        "software",
        "hydrology"
      ],
      "source_manual_count": 194,
      "regional_notes": [],
      "summary": "Tools commonly required or accepted for sizing and flood routing."
    },
    {
      "id": "water-quality",
      "title": "Water Quality Volume and Treatment",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.48,
      "topic_tags": [
        "water_quality"
      ],
      "source_manual_count": 286,
      "regional_notes": [
        "arid_west",
        "cold_climate"
      ],
      "summary": "Sizing basis for water-quality capture/treatment and pollutant-removal expectations."
    },
    {
      "id": "water-quality.sizing",
      "title": "WQv / Treatment Volume Sizing Methods",
      "level": 2,
      "parent_id": "water-quality",
      "prevalence": 0.48,
      "topic_tags": [
        "water_quality"
      ],
      "source_manual_count": 286,
      "regional_notes": [
        "arid_west"
      ],
      "summary": "Common approaches: first inch, 90th percentile, percent annual rainfall, TSS removal targets."
    },
    {
      "id": "channel-flood",
      "title": "Channel Protection, Detention, and Flood Control",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.46,
      "topic_tags": [
        "detention",
        "peak_flow"
      ],
      "source_manual_count": 273,
      "regional_notes": [
        "arid_west",
        "urban_infill"
      ],
      "summary": "Post-development peak matching, extended detention, and floodplain/channel criteria."
    },
    {
      "id": "channel-flood.release",
      "title": "Allowable Discharge and Release Rates",
      "level": 2,
      "parent_id": "channel-flood",
      "prevalence": 0.46,
      "topic_tags": [
        "detention",
        "peak_flow"
      ],
      "source_manual_count": 273,
      "regional_notes": [],
      "summary": "Pre- vs post-development peaks and site-specific release limits."
    },
    {
      "id": "bmps",
      "title": "Stormwater Control Measures (BMPs)",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.48,
      "topic_tags": [
        "bmp_sizing"
      ],
      "source_manual_count": 289,
      "regional_notes": [
        "karst",
        "arid_west",
        "cold_climate"
      ],
      "summary": "Approved practice categories, selection hierarchy, and sizing/design criteria."
    },
    {
      "id": "bmps.selection",
      "title": "BMP Selection and Treatment Trains",
      "level": 2,
      "parent_id": "bmps",
      "prevalence": 0.48,
      "topic_tags": [
        "bmp_sizing"
      ],
      "source_manual_count": 289,
      "regional_notes": [],
      "summary": "How manuals prioritize infiltration, filtration, and proprietary devices."
    },
    {
      "id": "bmps.sizing",
      "title": "Facility Sizing and Design Criteria",
      "level": 2,
      "parent_id": "bmps",
      "prevalence": 0.5,
      "topic_tags": [
        "bmp_sizing",
        "water_quality"
      ],
      "source_manual_count": 288,
      "regional_notes": [
        "cold_climate",
        "arid_west"
      ],
      "summary": "Geometry, media, drawdown, setbacks, and underdrain requirements by practice type."
    },
    {
      "id": "bmps.manufactured",
      "title": "Manufactured / Proprietary Treatment Devices",
      "level": 2,
      "parent_id": "bmps",
      "prevalence": 0.48,
      "topic_tags": [
        "bmp_sizing"
      ],
      "source_manual_count": 289,
      "regional_notes": [],
      "summary": "Approval lists, verification programs, and when MTDs may substitute for GI."
    },
    {
      "id": "construction-esc",
      "title": "Construction Stormwater and ESC",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.55,
      "topic_tags": [
        "construction_esc"
      ],
      "source_manual_count": 297,
      "regional_notes": [],
      "summary": "Temporary controls during construction; often in separate manuals from post-construction."
    },
    {
      "id": "om",
      "title": "Inspection, Operations, and Maintenance",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.5,
      "topic_tags": [
        "om"
      ],
      "source_manual_count": 290,
      "regional_notes": [],
      "summary": "Long-term O&M obligations, inspection frequency, and enforcement hooks."
    },
    {
      "id": "regional",
      "title": "Regional and Site Constraints",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.49,
      "topic_tags": [
        "hydrology",
        "bmp_sizing"
      ],
      "source_manual_count": 292,
      "regional_notes": [
        "arid_west",
        "cold_climate",
        "karst",
        "coastal"
      ],
      "summary": "Where national defaults must fork: climate, soils, geology, and receiving-water sensitivity."
    },
    {
      "id": "submittals",
      "title": "Plan Submittal, Review, and Variances",
      "level": 1,
      "parent_id": null,
      "prevalence": 0.25,
      "topic_tags": [
        "general"
      ],
      "source_manual_count": 75,
      "regional_notes": [],
      "summary": "Documentation expected for approval and paths for alternatives."
    }
  ]
}