New Development / C.3
In October 2009, the San Francisco Bay Regional Water Quality Control Board (RWQCB) 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 adopted similar requirements for eastern Contra Costa cities in September 2010.
Provision C.3 of the preceding permit included specific requirements for development projects and was in effect from 2005 until 2009. Additional requirements are being phased in during the 5-year term of the MRP. The San Francisco Bay RWQCB amended the MRP on November 28, 2011.
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. Remaining runoff from impervious areas must be captured and used or 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
- A memo recommends submittal requirements for revised soil specifications for bioretention facilities (December 13, 2011)
- The MRP Low Impact Development (LID) requirements for private projects are in effect December 1, 2011. A 2-page Stormwater C.3 Update summarizes the changes to requirements in Contra Costa.
- The November 28, 2011 Amendment to the MRP is available on the San Francisco Bay Regional Water Quality Control Board's website.
- Memo on Vertical Position of Underdrains in Bioretention Facilities (February 22, 2011, 69 KB .pdf).
- Stormwater C.3 Guidebook 5th Edition, approved October 20, 2010. Supersedes the 3rd Edition in effect since September 2008.
- Email Michelle McCauley or call 925-313-2194 to join our email list for notices of training opportunities and updates to C.3 guidance.
- IMP Sizing Calculator available at the C.3 Guidebook page. It includes a help document.
