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Water: Best Management Practices

Post-Construction Stormwater Management in New Development & Redevelopment

Infiltration islands in parking lots can help reduce stormwater runoff.

For the past two decades the rate of land development across the country has been more than two times greater than the rate of population growth.  If unchecked, the increased impervious surface associated with this development will increase stormwater volume and degrade water quality, which can harm lakes, rivers, streams, and coastal areas.

The best way to mitigate stormwater impacts from new developments is to use practices to treat, store, and infiltrate runoff onsite before it can affect water bodies downstream.  Innovative site designs that reduce imperviousness and smaller-scale low impact development practices dispersed throughout a site are excellent ways to achieve the goals of reducing flows and improving water quality. 

Phase II MS4s are required to address post-construction stormwater runoff from new development and redevelopments that disturb one or more acres. This primarily includes developing:

  • Strategies to implement a combination of structural and non-structural BMPs,
  • An ordinance to address post-construction runoff, and
  • A program to ensure adequate long-term operation and maintenance of BMPs.

Additional information on this minimum measure, including the stormwater Phase II regulatory requirements for post-construction and a fact sheet on the post-construction minimum measure (3 pp, 223K, About PDF), is also available.

Key BMPs and Resources:
MS4s addressing the post-construction minimum measure should focus on the following four key BMPs to help them in developing a post-construction program. Information on low impact development and smart growth are key resources for MS4s. The additional BMPs in the next section describe practices that developers could use to comply with an MS4's post-construction program.
BMP Fact Sheets:

The fact sheets in this section describe BMPs and how to use them to help municipal stormwater programs and construction site operators comply with the stormwater Phase II requirements.

EPA has started updating these fact sheets to include new practices and technologies. Several of these updated fact sheets are now available in PDF format. 

Municipal Program Elements

  BMP Inspection and Maintenance
  Ordinances for Post-construction Runoff
  Post-construction Plan Review
Innovative BMPs for Site Plans 
  Alternative Turnarounds
  Conservation Easements
  Development Districts
  Eliminating Curbs and Gutters
  Green Parking
  Green Roofs
  Infrastructure Planning
  Low Impact Development (LID) and Other Green Design Strategies
  Narrower Residential Streets
  Open Space Design
  Protection of Natural Features
  Riparian/Forested Buffer
  Street Design and Patterns
  Urban Forestry
  Grassed Swales
  Infiltration Basin
  Infiltration Trench
  Permeable Interlocking Concrete Pavement
  Pervious Concrete Pavement
  Porous Asphalt Pavement
  Bioretention (Rain Gardens)
  Catch Basin Inserts
  Sand and Organic Filters 
  Vegetated Filter Strip
  Dry Detention Ponds
  In-Line Storage
  On-Lot Treatment
  Stormwater Wetland
  Wet Ponds
  Alum Injection
  Manufactured Products for Stormwater Inlets 

EPA Internet Resources:        
Other Internet Resources:

Note: If you are referencing this page, please use this alias web address: http://www.epa.gov/npdes/stormwater/menuofbmps/postconstruction

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