Construction and Development
Construction Site Runoff Control

Runoff from construction and development sites poses a serious risk to water quality downstream. To mitigate this risk, there are two National Pollutant Discharge Elimination System (NPDES) permits that regulate runoff from construction sites: NPDES Construction General Permit (CGP) and NPDES Municipal General Permit.

NPDES Construction General Permit

All construction projects that disturb one or more acres, or smaller sites that are part of a larger plan of development, are required to obtain coverage under the Construction General Permit
  • Construction General Permit (CGP): State Water Board requirements for obtaining coverage: http://www.waterboards.ca.gov/water_issues/programs/stormwater/constpermits.shtml
  • The CGP requires the development and implementation of a Storm Water Pollution Prevention Plan (SWPPP). The EPA has provided guidance on developing a SWPPP: https://www.epa.gov/npdes/developing-stormwater-pollution-prevention-plan-swppp
  • Construction BMP Handbook - One of a series of handbooks developed by CASQA to provide guidance on selecting and implementing BMPs to reduce pollutant discharge from construction sites. Available for download for free: http://www.casqa.org/resources/bmp-handbooks  
  • Construction Industry Compliance Assistance Center (CICA) - The CICA provides information on how to comply with federal and State laws that regulate stormwater runoff, air quality, hazardous materials and wastes, and endangered species. This information is provided free of charge by the National Center for Manufacturing Sciences with the assistance of the Associated General Contractors of America and the National Association Home Builders, and funding from the United States Environmental Protection Agency (EPA): http://www.cicacenter.org

NPDES Municipal General Permit

Solano County must require development projects to comply with Provision E.12 of the State Water Resources Control Board (State Water Board) under the Phase II NPDES Municipal Stormwater Permit.

Phase II NPDES Municipal Stormwater Permit - scroll to E.12 to view Construction Requirements: http://www.swrcb.ca.gov/water_issues/programs/stormwater/docs/phsii2012_5th/order_final.pdf

Under this new requirement, project applicants must incorporate Low Impact Development (LID) design practices into their projects. All construction and grading projects that create 2,500 square feet or more of impervious surface in unincorporated Solano County are required to obtain coverage under the NPDES Municipal Permit by obtaining a grading permit. The following guidance and templates are provided to assist in compliance with these new requirements:

Sizing Calculators - As part of E.12 requirements, project proponents must use State Water Board SMARTS Post-Construction Calculator, or equivalent, to quantify the runoff reduction resulting from implementation of site design measures. The following calculators may be used for this provision:

Please contact Public Works at 707.784.6765 for more information on how to apply for a grading permit.