Set of models built for establishing nutrient loading targets for Santa Margarita River

SCCWRP and its partners have finished assembling an integrated toolkit of mechanistic computer models and empirical statistical models that water-quality managers can use to optimally protect biological integrity and human uses in the lower mainstem of the Santa Margarita River.

The work, completed in April, is part of a three-year project to develop scientifically defensible nutrient loading targets for reducing eutrophication in the lower Santa Margarita River watershed.

The Santa Margarita River watershed, which spans Riverside and northern San Diego Counties, has been grappling with algal proliferation and low dissolved oxygen as a result of excess nutrient and organic matter inputs.

This fall, researchers will begin developing receiving-water models for the river’s upper mainstem that will be connected to the lower mainstem models, enabling researchers to predict the degree to which nutrient load reductions and other management strategies would reduce eutrophication.

This work serves as a key California case study for test-driving technical elements of a proposed State Water Board biointegrity-biostimulatory policy to govern the health of wadeable streams statewide.