New Development / C.3
In October 2009, the San Francisco Bay Regional Water Quality Control Board adopted a Municipal Regional Permit (MRP) governing discharges from municipal storm drains operated by 76 local government entities, including those in western and central Contra Costa County. The Central Valley Regional Water Quality Control Board will consider adopting similar requirements soon. In the meantime, eastern Contra Costa cities are implementing the MRP requirements.
Provision C.3 of the preceding permit included specific requirements for development projects and was in effect from 2005 until 2009. Additional requirements will be phased in during the 5-year term of the MRP.
The C.3 requirements are separate from, and in addition to, requirements for erosion and sediment control and for pollution prevention measures during construction.
Project site designs must minimize the area of new roofs and paving. Where feasible, pervious surfaces should be used instead of paving so that runoff can infiltrate to the underlying soil. Runoff from impervious areas must be captured and treated. The MRP specifies the sizes and types of facilities that may be used.
In addition, project applicants must prepare plans and execute agreements to ensure the stormwater treatment and flow-control facilities are maintained in perpetuity.
Through the Contra Costa Clean Water Program, Contra Costa municipalities have prepared a Stormwater C.3 Guidebook to assist applicants through the process of submittals and reviews.
Most publications accessible from this page are formatted for both on-line navigation and 2-sided printing. Many require Adobe Acrobat Reader 7.0 or later, available free at www.adobe.com.
What’s New
- Email Michelle McCauley or call 925-313-2194 to join our email list for notices of training opportunities and updates to C.3 guidance.
- Stormwater C.3 Update Fact Sheet, describing upcoming changes to requirements in compliance with the Municipal Regional Permit (2 pp., March 2, 2010, 193 KB .pdf).
- October 2009 supplement to the Stormwater C.3 Guidebook, including two new Integrated Management Practices and an updated table with IMP sizing factors and equations, available on the C.3 Guidebook page.
- Updated IMP Sizing Calculator now available at the C.3 Guidebook page. It includes a help document.
- Presentation slides and handouts from the October 29, 2009 workshop for Land Development Professionals and municipal staff on the Workshops and Conferences page.
- Guidebook Appendix B: Soils, Plantings, and Irrigation for Bioretention Facilities (January 21, 2009, 337 KB .pdf)
- Stormwater C.3 Guidebook 4th Edition, approved September 17, 2008. Supersedes the 3rd Edition in effect since October 2006.
- Model Stormwater Facilities Construction Checkllist (February 21, 2009, 93 KB .doc)
- Model Stormwater Facility Operation and Maintenance Inspection Report form (February 21, 2009, 35 KB .doc)
- Policy on Selection of Stormwater Treatment Facilities for Maximum Extent Practicable Effectiveness in Compliance with NPDES Provision C.3 (March 21, 2007, 146 KB .pdf)
