Important! The Project Clean Water website has just been updated. Please review the Site Map Page to see the new website structure. 

2013 MS4 Permit

Overview

In May 2013, the California Regional Water Quality Control Board for the San Diego Region reissued (SDRWQCB) a municipal storm water, National Pollutant Discharge Elimination System permit (Municipal Separate Storm Sewer Systems [MS4] Permit) that covered its region. The San Diego Region is comprised of San Diego, Orange, and Riverside County Copermittees. The MS4 Permit reissuance to the San Diego County Copermittees went into effect in 2013 (Order No. R9-2013-0001).

The reissued MS4 Permit updates and expands storm water requirements for new developments and redevelopments. In February 2015, the MS4 Permit was amended by Order R9-2015-0001, and again in November 2015 by Order R9-2015-0100. As required by the reissued MS4 Permit, the Copermittees have prepared this Model Best Management Practices (BMP) Design Manual (also referred to as the “manual”) to replace the current Countywide Model Standard Urban Stormwater Mitigation Plan (SUSMP), dated March 25, 2011, which was based on the requirements of the 2007 MS4 Permit. The effective date of this manual is February 16, 2016.

Model BMP Design Manual

The San Diego County Copermittees have developed a Model BMP Design Manual for the San Diego Region to conform to new development requirements of the 2013 Municipal Storm Water Permit (Order No. R9-2013-0001). The Model BMP Design Manual provides procedures for planning, selecting and designing onsite structural BMPs for new development and significant redevelopment projects in accordance with Provision E.3 of the 2013 Permit. Additionally, the Regional Manual provides a basis for the development of local BMP Design Manuals by each Stormwater Copermittee in the San Diego region.

Each Copermittee must update its local BMP Design Manual in accordance with the content of the regional Model on or before the February 16, 2016 effective date of the updated requirements of the 2013 Permit. The final Model BMP Design Manual and appendices are attached below, along with applicable supporting documentation and resources. If you have questions about the technical aspects of the manual, please use this Online Help Desk.

The Copermittees have updated the 2016 Model BMP Design Manual to provide more guidance. This is provided in the 2018 edition linked to below. Also, version 3.1 of the BMP Sizing Spreadsheet is available in the link below.

MAY 2018 MODEL BMP DESIGN MANUAL AND APPENDICES FOR SAN DIEGO REGION

FEBRUARY 2016 MODEL BMP DESIGN MANUAL AND APPENDICES FOR SAN DIEGO REGION

INFILTRATION INFEASIBILITY DOCUMENTATION GUIDELINES

BMP MAINTENANCE FACT SHEETS

POTENTIAL CRITICAL COARSE SEDIMENT YIELD AREAS MAP (From Regional WMAA)

HMP EXEMPTION MAPPING  (From Regional WMAA)

SUMMARY ON MANNING’S “N” VALUES FOR OVERLAND FLOW USING EPA SWMM V.5

WHITE PAPER ON MANNING”S “N” VALUES FOR OVERLAND FLOW USING EPA SWMM V.5

WHITE PAPER ON SAN DIEGO BIORETENTION MEDIA SURVEY

SAN DIEGO HYDROLOGY MODEL 3.1 (Note: Do not load projects from SDHM 3.0 into SDHM 3.1 because different HSPF parameter values are used.)

RAIN GAUGE DATA

BMP Sizing Spreadsheet V3.1

BMP Sizing Spreadsheet User Guide

The user’s guide provides instructions on how to use the BMP Sizing Spreadsheet. Please note that the user’s guide was prepared for the previous version of the BMP Sizing Spreadsheet (V1.04). The guide contains much useful information, especially for those completing the spreadsheet for the first time, relevant to properly completing the current BMP Sizing Spreadsheet.

San Diego BMP Sizing Calculator Methodology

For additional information contact the jurisdiction your project is located in.

Notes:

  • This BMP Sizing Spreadsheet is a tool offered to assist the public with permit compliance, but its use is not intended to guarantee or warrant compliance, which is the independent responsibility of the user. In no event will the San Diego area municipal Copermittees be liable for any incidental, special or consequential damages of any kind (including, but not limited to, loss of information or other monetary loss) arising in any way in connection with the use or inability to use the BMP Sizing Calculator accessed from this website.

For technical questions about the Model BMP Design Manual, please use the Online Help Desk. For jurisdiction-specific information, please visit the Development Standards page.

Model BMP Design Manual Help Desk

Welcome to the Help Desk for the Model BMP Design Manual for the San Diego region. The Model BMP Design Manual addresses updated onsite post-construction storm water requirements and provides procedures for planning, preliminary design, selection, and design of permanent storm water BMPs based on the performance standards required by the MS4 Permit for the San Diego Region [Order No. R9-2013-0001 as amended by R9-2015-001 and R9-2015-0100].

The Help Desk is intended to provide a platform to submit technical questions regarding the Model BMP Design Manual.
Non-technical questions related to jurisdiction-specific requirements such as submittal requirements, approval process, project-specific questions and policy-related issues should be directed to the applicable municipality/agency (List of Jurisdictional Contacts).

Submissions are accepted by email only*. A reply will be provided within 5 working days from day of submission. Please note that a compilation of questions and responses will be posted in the Questions and Answers Log in a timely manner; name and contact information of submitter will not be posted. Please check the log to see if your question has been answered already.
Please submit all technical questions to the Help Desk email address: [email protected]
*Email submission information should include the following to best ensure a timely and helpful response:

  • Indicate the specific section/appendix of the Model Manual that pertains to the question. If appropriate, also indicate specific figure, table, or equation by number/name.
  • Questions should be as specific as possible to facilitate responses.
  • Supply contact information of submitter (information will not be posted in response log).

Water Quality Equivalency Guide

The 2013 MS4 Permit allows Priority Development Projects to satisfy onsite structural BMP performance requirements through participation in an Offsite Alternative Compliance Program. Development and implementation of this program is optional and at the discretion of each jurisdiction. To serve as a foundation for jurisdictions interested in pursuing such a program, a number of supporting elements have been pursued at a regional level. One such effort was the establishment of a Water Quality Equivalency (WQE) guidance document which provides applicants a method to demonstrate that construction of an offsite Alternative Compliance Project results in a greater overall water quality benefit than simply satisfying onsite structural BMP performance requirements associated with the Priority Development Project.

On December 17, 2015, the San Diego Regional Water Quality Control Board (RWQCB) accepted the Water Quality Equivalency Guidance Document for Region 9. On March 15 2019, the San Diego RWQCB accepted an updated version dated 2018. Both are available for download below. This guidance document establishes a mechanism to correlate quantifiable Alternative Compliance Project water quality benefits with Priority Development Project water quality impacts and ultimately demonstrate that the ACP benefits outweigh the PDP impacts. Pursuant to the requirements set forth in Provision E.3.c.(3)(a) of the Permit, the methods presented within this guidance must be incorporated as part of any optional Offsite Alternative Compliance Program developed by a Copermittee. Interested project applicants should reach out to their applicable jurisdiction for more specific information about these optional program elements.

For further information and questions regarding the development of the Offsite Alternative Compliance Program, please contact Sheri McPherson, County of San Diego, at [email protected]

Water Quality Equivalency Guidance (2018)

Archived Reference Material:

2015 WQE Guidance Material

Watershed Management Area Analysis (WMAA)

The Watershed Management Area Analysis (WMAA) is an optional element for inclusion in the Water Quality Improvement Plans (WQIPs) described in the 2013 MS4 Permit (Provision B.3.b.(4)). This analysis is intended to characterize important hydrologic processes and characteristics of each watershed through the creation of GIS layers that may be used to identify candidate projects that could potentially be used as offsite alternative compliance options in lieu of satisfying full onsite retention, biofiltration, and hydromodification runoff requirements, and to identify and/or prioritize areas where it is appropriate to allow certain exemptions from onsite hydromodification management BMPs.

In July 2013, the Copermittees elected to conduct the watershed characterization and hydromodification management exemption mapping on a regional scale to allow for uniform development of the WMAA elements for each of the 9 San Diego-area watershed management areas (WMAs) within the County of San Diego. The development of the WMAA provides the foundation to allow for implementation of the optional Offsite Alternative Compliance Program as described in Provision E.3.c.(3) of the permit.

For further information and questions regarding WMAA, please contact Sheri McPherson, County of San Diego, at [email protected].

FINAL WMAA REPORT:

San Diego County Regional WMAA Report with Appendices  (October 2015)

Factor of Safety Memo  (June 2015)

COMPREHENSIVE WMAA MAPPING:

WMAA Mapping Data from Attachment C (October 2018)

Comprehensive WMAA mapping files may be periodically updated to reflect revisions from WQIP Annual Reporting process. (Otay River HMP Exemption added on May 26, 2017; Critical Coarse Sediment layer now incorporated into Google Earth mapping, August 22, 2017; Escondido Creek HMP exemption added on October 18, 2018).

Disclaimer: Mapping data is provided to assist the public with permit compliance, but its use is not intended to guarantee or warrant compliance, which is the independent responsibility of the user. Mapping is intended to be used in conjunction with the process described in the Model Regional BMP Design Manual. In no event will the San Diego area municipal Copermittees be liable for any incidental, special or consequential damages of any kind (including, but not limited to, loss of information or other monetary loss) arising in any way in connection with the use or inability to use the mapping accessed from this website.

Training Materials