SMRWMA Map The Co-permittees in the Santa Margarita Watershed Management Area (WMA) work cooperatively to implement the requirements of the Regional MS4 Permit (Order No. R9-2013-0001, as amended by R9-2015-0001 and R9-2015-0100) issued by the California Regional Water Quality Control Board, San Diego Region. This clearinghouse provides public access to all of the plans, reports, maps, and supporting information required to implement the Regional MS4 Permit. The Water Quality Improvement Plan (WQIP) is the overarching watershed plan, whereas the Jurisdictional Runoff Management Program (JRMP) documents provide more details regarding implementation.

Santa Margarita WMA Stakeholder Agencies

The Riverside County Flood Control and Water Conservation District (Principal Permittee)
The County of Riverside California Department of Transportation The County of San Diego
Cities in Riverside County: Menifee Murrieta Temecula Wildomar

Santa Margarita Watershed Management Area Resource Library

Water Quality Improvement Plan (WQIP) Annual Reports Report Of Waste Discharge (ROWD) 2017 Maps and Data
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Santa Margarita River Nutrient Initiative – Stakeholder Group

Background Stakeholder Effort Resources Monitoring

The Santa Margarita Watershed Nutrient Initiative – Stakeholder Group, composed of a broad range of stakeholders with diverse interests, was formed in 2012 to address nutrient issues in the Santa Margarita River Watershed. This Stakeholder Group, with support from a Technical Advisory Committee, is working through a collaborative, inclusive, and regional process, using state of the science techniques, to develop regulatory targets and monitoring programs, and to recommend management approaches to ensure that the biological, chemical, and physical integrity of the Santa Margarita River and its tributaries are protected.

Technical investigations were initiated in 2006 by the San Diego Lagoons Investigative Order (R9-2006-0076). Phases I and II of follow-up grant-funded technical work developed models to apply a nutrient numeric endpoint methodology to evaluate nutrient impacts to the SMR Lagoon, collected comparable data for nutrient loading and transport processes, and developed regulatory targets for the Lagoon. Through evaluation of the model simulations and discussions during the collaborative development of the targets, the stakeholders have achieved a greater understanding of the seasonal impact of nutrients on the beneficial uses. Phase I and II efforts were conducted from 2011 to 2018 and were supported by Proposition 84 IRWM grant funds.

In early 2019, the group initiated Phase III of the Project, which extends the work conducted for the Lagoon in Phases I and II to explore a range of biostimulatory targets that are protective of beneficial uses in the Santa Margarita River main stem under the present climate conditions and under climate change and/or extreme climate scenarios. Phase III will also identify potential restoration actions to improve biointegrity and reduce eutrophication, and will calculate load and waste load allocations required to meet the proposed biostimulatory targets. The technical work in Phase III is being funded by the San Diego Water Board.

If you are interested in participating in this process, please contact the Chairperson of the Initiative Group via e-mail.

Chairperson: Matt Yeager

Riverside County Co-permittees Resources

As required by the San Diego Regional Municipal Stormwater NPDES Permit, all new and resubmittals of WQMPs shall use the 2018 WQMP Manual. All previous WQMP versions are no longer in effect.

Other Resources: San Diego County Permittee Resources

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