In May 2013, the California Regional Water Quality Control Board for the San Diego Region reissued (SDRWQCB) a municipal stormwater, 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 R9-2013-0001).
The reissued MS4 Permit updates and expands stormwater requirements for new developments and redevelopments. In February 2015, the MS4 Permit was amended by Order R9-2015-001. As required by the reissued MS4 Permit, the Copermittees have prepared this Model Best Management Practices (BMP) Design Manual (from here in 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.
What this Manual is intended to address:
This Manual addresses updated on-site post-construction stormwater requirements for Standard Projects and Priority Development Projects (PDPs), and provides updated procedures for planning, preliminary design, selection, and design of permanent stormwater BMPs based on the performance standards presented in the MS4 Permit. This manual is intended to be used as the basis for jurisdiction-specific BMP Design Manuals as described in the "Local Implementation" section below.