Stormwater Management Facilities Report Outline

Stormwater Management Facilities Report Outline

  1. Executive Summary
  2. Introduction
    • Evaluation of Existing Conditions
      • Discussion of existing site conditions with Existing Site Resources Map, prepared per Site Design Guidance
      • Determination of whether site is new development or redevelopment
      • Determination of minor watershed and whether release rate or zero differential detention requirements apply (for projects with detention)
      • Determination of any special existing conditions that warrant mitigation
    •  Evaluation of Proposed Conditions Development use
      • Define total disturbed area in acres
      • Calculate differential runoff for 15-year 20-min (St. Louis County) or 20-year 20-min (St. Louis City) storm
      • Description of stormwater management facilities proposed, with BMP Drainage Area Map (see BMP Drainage Area Map instructions)

3. Water Quality/Channel Protection/Flood Protection MEP Calculation Tool (as applicable)


  • Sizing of stormwater quality BMPs – Include volume reduction calculations
  •  Sizing of channel protection basin – Volume, rate, and orifice size calculations
  •  Flood protection detention basin report – See flood detention report checklist

Hydraulic Calculations

  • Pipe sizing/hydraulic grade line calculations
  • Culvert calculations
  • Open channel calculations
  • Any special structures (e.g. water quality flow splitter device)
  • Flow velocities/erosion/revetment calculations


  • Existing Site Resources Map
  • BMP Drainage Area Map
  • Infiltration Tests/Borings/Geotech report
  • BMP Reserve Area Plat (Maintenance Agreement Checklist)
  • Proprietary BMP Cut-Sheets and O&M Manuals
  • Structural Calculations
  • BMP Typical Section

4. Operation and Maintenance Plan (Separately Bound) (Operation and Maintenance Plan Guidance)

  • Post-construction Stormwater Management Site Plan and Drawings
  • General Stormwater Management Facilities Description
  • Site Contacts and Change of Ownership
  • Facility Maintenance Plan
  • BMP Type Specific Inspection Checklists & Description
  • Annual Reporting Requirement
  • BMP Waste Disposal
  • Maintenance Agreement
  • O&M Plan Revision