Introduction
The beaches adjacent to the mouths of Ramirez Canyon Creek (RCC) and Escondido Canyon Creek (ECC) have exhibited high levels of fecal indicator bacteria. Weekly Heal the Bay (HtB) Beach Report Cards indicate that poor beach conditions occurred at Paradise Cove beach (near the mouth of RCC) about 20% of the time during the dry weather season from 1998-2003 and 65% of the time from 2004 through 2006. Monitoring data near the mouth of ECC are more temporally limited, but indicate poor dry weather beach conditions 98% of the time between the start of sampling in 2005 through the first half of 2006, though poor conditions occurred less than 5% of the time in the second half of 2006 when a berm is believed to have prevented ECC flow from reaching the ocean.
Resolving the problems causing poor beach water quality conditions requires an understanding of bacterial sources, which is unclear in these systems. Bacteria can originate from multiple possible sources in these watersheds, including residential inputs, horse corrals, septic systems, wildlife inputs from open spaces at the upper portions of the watersheds, and shorebirds on the beaches. Selecting the most immediate remedial actions to improve conditions at the beach is difficult until the sources are better understood.
This difficulty of source identification is not unique to these systems. AB 538 , adopted by the State of California on September 27, 1999, required the State to prescribe protocols for source identification studies, but the science of source identification was not well developed enough at the time of the legislation for this to be effective. In addition, there were few case studies to illustrate how these techniques could be incorporated into a comprehensive and cost-effective site evaluation. Since that time, the scientific tools have advanced, making the development of assessment protocols more feasible.
To help develop procedures that will lead to cleaner beaches, the Los Angeles County Board of Supervisors allocated funding for bacterial source assessments to be conducted in ECC and RCC. The goal of this project is to use Ramirez and Escondido Canyons as prototypes to develop bacteria source identification protocols, and while doing so, identify the primary bacterial sources in these two watershed systems. This study plan describes that program.
Click here to view the entire study plan.
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