Stormwater C.3 Guidebook
Stormwater C.3 Guidebook 6th Edition and Addenda
Click on this link to download the Stormwater C.3 Guidebook 6th Edition (February 15, 2012, 2.0 MB .pdf formatted for 2-sided printing).
Here is a memorandum describing changes from the Guidebook 5th Edition.
Addenda and updates to the 6th Edition
- Click here to download the updated bioretention soil media specification approved April 18, 2016. (See BASMAA and Executive Officer letters for an explanation of the changes.)
- Click here to download the March 2016 “Stormwater C.3 Update.” The update is an addendum to the C.3 Guidebook, 6th Edition, and incorporates key changes to Provision C.3 in the Municipal Regional Stormwater Permit (MRP 2.0).
- Click here to download the March 20, 2013 Guidebook Addendum, “Contra Costa Clean Water Program Technical Criteria for Non-LID Facilities.” These criteria apply to tree-box-type high-flowrate biofilters and vault-based high-flowrate media filters when proposed for use on Special Projects (see the Guidebook 6th Edition, page 58).
- Click here to download the December 1, 2012 Guidebook Addendum, “Preparing a Stormwater Control Plan for a Small Land Development Project,” in compliance with Municipal Regional Permit Provision C.3.i. The guidance applies to projects that create or replace 2,500 square feet or more, but less than 10,000 square feet, of impervious surface.
Additional Guidebook Resources
Stormwater Control Plan Template
The template is updated and consistent with the Stormwater C.3 Guidebook 6th Edition (138KB .doc).
IMP Sizing Calculator
Released October 2009. Consistent with the 6th Edition. Be sure to review and follow Guidebook instructions for preparing a complete Stormwater Control Plan. Calculator and setup file (3MB .zip). After installing the calculator, read the help file. If attempting to run the calculator results in an error message, try right-clicking the icon and selecting “Run as Administrator.”
Appendix A: Local Exceptions and Requirements
Municipality-specific procedures, policies and submittal requirements should be obtained from the municipality’s planning and community development department.
Follow the link to the local municipality website:
- City of Antioch
- City of Brentwood
- City of Clayton
- City of Concord
- Town of Danville
- City of El Cerrito
- City of Hercules
- City of Lafayette
- City of Martinez
- Town of Moraga
- City of Oakley
- City of Orinda
- City of Pinole
- City of Pittsburg
- City of Pleasant Hill
- City of Richmond
- City of San Pablo
- City of San Ramon
- City of Walnut Creek
- Contra Costa County
Appendix B: Soils, Plantings, and Irrigation for Bioretention Facilities
The soil specification approved April 18, 2016 includes the following statement: “Local soil products suppliers have expressed interest in developing ‘brand-name’ mixes that meet these specifications. At their sole discretion, municipal construction inspectors may choose to accept test results and certification for a ‘brand-name’ mix from a soil supplier.”
For the convenience of the land development community, the Contra Costa Clean Water Program invited local soil suppliers to request listing here. The following suppliers submitted test results and certifications. Listing does not imply or guarantee that the mix as designed or delivered meets all requirements of the soil specification. Contractors and construction inspectors should independently obtain and review the required information before approving installation of a ‘brand-name’ soil mix.
- L.H. Voss
- Contra Costa Topsoil
- American Soil Products
- Pleasanton Trucking
- Marshall Brothers Enterprises
Policies and content of the following memoranda have been incorporated into the 6th Edition. The memoranda include some additional background and explanatory material.
- Memo on Vertical Position of Underdrains in Bioretention Facilities (February 22, 2010, 69KB .pdf)
- Policy for C.3 Compliance for Subdivisions (26 KB .pdf)
Guidance for HSPF Modeling (for Hydromodification Management)
For compliance with flow-control requirements using Option 3 in Appendix C of the 6th Edition (memo 763 KB .pdf)
Basic Geomorphic Assessment Methods and Criteria
For compliance with flow-control requirements using Option 4b in Appendix C of the 6th Edition. Contact the Program to obtain a copy.
Contra Costa Hydrology Data
- Isohyetal Map (Drawing B-166), 11″ x 17″, Low Resolution, 630 KB .pdf
- Isohyetal Map (Drawing B-166), 11″ x 17″, High Resolution, 10.6 MB .pdf
- Chart: Unit Basin Storage Size for 80% Capture. 8½” x 11″, 17 KB .pdf
- Contra Costa Hourly Rainfall Data (for continuous runoff simulation modelers) 1 MB .zip
Example Stormwater Control Plans
Please note these example plans were prepared in compliance with previous editions of the Stormwater C.3 Guidebook. They are made available as examples for format and presentation.
- Stormwater Control Plan for the Nove Property (158 KB .pdf)
- Nove Property Exhibit (4 MB .pdf)
- Stormwater Control Plan for Almondridge residential subdivision (741 KB .pdf)
- Stormwater Control Plan for Rose Garden commercial development (668 KB .pdf)
- Rose Garden Exhibit (1.4 MB .pdf)
Operation and Maintenance of Stormwater Facilities
The following documents are in MS Word and may be incorporated into Stormwater Facilities Operation and Maintenance Plans. See Chapter 6 of the Stormwater C.3 Guidebook, 6th Edition
- Designation of Responsible Individuals
- Stormwater Facilities Inspection and Maintenance Log
- Sample Contents of Stormwater Facilities Inspectors Report
Operation and Maintenance Fact Sheets
The following fact sheets provide general information on maintenance of stormwater facilities. In the Stormwater Facilities Operation and Maintenance Plan, this information should be augmented with information specific to the facility and the site.
- Fact Sheet for Bioretention Facilities
- Fact Sheet for Planter Boxes
- Fact Sheet for Dry Wells
- Fact Sheet for Wet Ponds, Constructed Wetlands, and Extended Detention Basins
Example Operation and Maintenance Plans
The following plan is provided as an example. Requirements tend to be project-specific and should be discussed with staff of the municipality having jurisdiction.