Post-Construction Best Management Practices

The following is a list of resources available for developers, builders and other project applicants with information on the use of site design, source control and treatment control Best Management Practices (BMPs) to control the quality and quality of runoff during the use of development projects.  

Bay Area  Stormwater Management Agencies Association (BASMAA) Post Construction Manual for Phase II Municipalities

The BASMAA Post Construction Manual for Phase II Municipalities (PDF) is intended to help development project applicants design and submit their projects BASMAA Post-Construction Manual (PDF)for approval. It applies to projects in all the municipalities in the Napa Countywide Stormwater Pollution Prevention Program (NCSPPP) service area including the cities of Napa, American Canyon, St. Helena, and Calistoga, the Town of Yountville and the County of Napa.  To help applicants calculate the size of bioretention features, download the Post Construction Sizing Calculator (XLSX).

Example Projects

2 Hypothetical Example Projects were developed (residential subdivision and commercial project) for the assistance of project applicants. The following is an example Stormwater Control Plan (SCP) and Operation and Maintenance (O&M) Plan for these projects, along with completed sizing calculator spreadsheets:

Related Documents

Residential Subdivision

  1. Example Bioretention Sizing Calculator for residential (PDF)
  2. Example O&M Plan for Residential (PDF)
  3. Example SCP for Residential (PDF)

Commercial Project

  1. Example Bioretention Sizing Calculator for Commercial (PDF)
  2. Example O&M Plan for Commercial (PDF)
  3. Example SCP for Commercial (PDF)

Soil Media Specifications & Suppliers

  1. Bioretention Soil Media Specification (PDF)
  2. Bioretention Soil Suppliers (PDF)

Submittals for bioretention soil should be accompanied by a completed Biotreatment Soil Mix Verification Checklist (PDF)

Non-LID Treatment Facilities

Pages 3-6 of the Manual (PDF) list circumstances in which non-LID treatment facilities are allowed

Technical Criteria for non-LID treatment facilities (PDF) describes conditions to achieve permit requirements

View the slides from the Annual Post Construction Training (PDF) held on February 27, 2019.

Hydromodification Management Requirements

Projects that create or replace 1 acre or more of impervious surface area (with a net increase in impervious) must meet the Phase II Permit hydromodification management requirements described in permit section E.12.F. Project applicants should follow the BASMAA Post Construction Manual to comply with E.12.F. For more information, read Evaluating Hydromodification Performance of Bioretention (PDF). 

Stormwater Best Management Practice Handbook - New Development & Redevelopment

This is one of a series of handbooks developed by the California Association of Stormwater Quality Agencies (CASQA) to provide guidance on selecting and implementing BMPs to reduce the discharge of pollutants from construction sites.  Click here for download.

Start at the Source, 1999 Edition & May 2003 Companion Document, BASMAA

Start at the Source (PDF) is intended for use in the planning and design phases of residential, commercial, institutional and industrial development and redevelopment.  It recognizes that one of the best opportunities to reduce the generation of urban runoff or “nonpoint source pollution” from development is through planning and design.

Post-Construction Stormwater BMPs in Action

A Guide of Post-Construction Stormwater BMPs in Action (PDF) provides examples that have been incorporated into the design of development projects in the northern half of the San Francisco Bay. 

Slow It, Spread It, Sink It

The user-friendly Slow It, Spread It, Sink It manual (PDF) describes simple ways homeowners can incorporate features into their landscape that treat stormwater runoff and recharge groundwater.