Water Quality Requirements for Land Development

On May 19, 2009, the Santa Ana Regional Water Quality Control Board adopted Order No. R8-2009-0030, NPDES No. CAS618030. On December 16, 2009, the San Diego Regional Water Quality Control Board adopted Order No. R9-200-0002, NPDES No. CAS018740. These Municipal NPDES Permits require the permittees (including the County of Orange, Orange County Flood Control District, and all of the cities of Orange County), to continue to implement stormwater quality management programs and develop additional programs in order to control pollutants in stormwater discharges.

Jurisdictional Boundaries

The City is split by the jurisdictional boundaries of 2 California Regional Water Quality Control Boards. The northwestern portions of the city fall under the requirements of the Santa Ana Regional Water Quality Control Board, and the southeastern portions of the city fall under the requirements of the San Diego Regional Water Quality Control Board. The jurisdictional boundaries are defined by the geographic division of watersheds; however, the boundary line can roughly be delineated by El Toro Road.

Model Water Quality Management Plan (WQMP)
 
In general accordance with Municipal NPDES Permits referenced above, the Model WQMP was developed by the County of Orange, the Orange County Flood Control District, and cities of Orange County (the permittees) to aid the permittees and development project proponents with addressing post-construction urban runoff and stormwater pollution from new development and significant redevelopment projects.

The Model WQMP describes the process for developing a Project WQMP for individual new development and significant redevelopment projects. A Project WQMP is a plan for minimizing the adverse effects of urbanization on site hydrology, runoff flow rates and pollutant loads.

Read more about WQMP requirements.
 
Santa Ana Regional Water Quality Control Board (SARWQCB)
 
Projects located within the SARWQCB jurisdiction should use the updated 2011 Model WQMP as approved by the SARWQCB on May 19, 2011. The Model WQMP becomes effective on August 17, 2011. The SARWQCB has developed 3 documents to support new development requirements:
The Model WQMP describes the requirements for preparing a Project WQMP. The TGD contains supporting technical guidance for how to complete these requirements and how to perform the technical analyses necessary to prepare a Project WQMP. The WQMP Template can be used to prepare a specific Project WQMP.

Development projects that do not meet the criteria for Priority Projects, as defined within the Model Water Quality Management Plan (see Model WQMP Sections 1.3 and 1.4), but that qualify as Non-Priority Projects as defined in the Drainage Area Management Plan should use the Non-Priority Project Water Quality Plan (NPP) (PDF) template for new development/significant redevelopment.

San Diego Regional Water Quality Control Board (SDRWQCB)
 
New land development requirements in general accordance with Order R8-2009-0002 were approved by the SDRWQCB and became effective December 20, 2013.

Several documents and other reference resources have been developed to support land development requirements within south Orange County including, but not limited to:
Additionally, land development projects that meet the criteria for Priority Projects are subject to Hydromodification Management Plan (HMP) (PDF) requirements.

WQMP Preparation Documents & Template
Additional Resources
 
A hydrologic model called the South Orange County Hydrology Model was developed to assist project proponents in selecting and sizing hydromodification controls.