UNINTENDED CONSEQUENCES OF NUTRIENT CRITERIA ON WATER RESOURCE PLANNING IN THE SANTA MARGARITA RIVER WATERSHED

The Santa Margarita River Watershed encompasses an area of approximately 740 square miles and falls within Riverside and San Diego Counties. As a result of the nutrient standards that have been applied within the watershed, no reclaimed water discharges to any part of the watershed. The potential dischargers have determined that at this time it is more cost effective to pipe reclaimed water to other watersheds with less stringent nutrient standards or permitting processes. Water supply solutions affected by the water quality standards include use of the reclaimed water in reuse, conjunctive use solutions, and water rights agreementsA watershed water quality model was constructed to address the issues of discharging reclaimed water effluent to the watershed. This model could be improved by inclusion of a module that addresses nutrient uptake by vegetation that exists within the stream channel of Murrieta Creek. In addition, riparian wetlands could help reduce nutrient loadings to streams within the watershed from stormwater runoff.