Paradise Cove beach in Malibu, CA, is at the outlet of Ramirez Canyon Creek. Note the storm drain outfall just to the left of the pier. Copyright © 2007 Kenneth Adelman, California Coastal Records Project.

The beaches adjacent to the mouths of Ramirez Canyon Creek (RCC) and Escondido Canyon Creek (ECC) have exhibited high levels of fecal indicator bacteria over the past few years.

Heal the Bay's weekly Beach Report Cards indicate poor beach conditions occurred at Paradise Cove beach (near the mouth of RCC) about 20 percent of the time during the dry weather season from 1998-2003 and 65 percent 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 percent of the time between the start of sampling in 2005 through the first half of 2006, though poor conditions occurred less than 5 percent 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. Collaboration between Heal the Bay, the County of Los Angeles and Southern California Coastal Water Research Project (SCCWRP) has brought about a four-phase source identification plan that began in March 2007.

• Phase 1
  The first phase will involve watershed-wide sampling to identify those sections of the creek system that contain sufficiently high levels of indicator bacteria to warrant further study.
• Phase 2
  The second phase will involve use of two advanced measures to assess whether human or horse fecal sources are present in the areas identified as hot sections in Phase 1.
• Phase 3
  The third phase will involve enhanced spatial and temporal sampling in those sections of the watershed identified as sources of greatest concern in the first two phases.
• Phase 4
  This last phase will be implemented if Phase 3 fails to identify specific sources, or if Phase 2 indicates that the bacterial sources are present system-wide, then library-based genetic methods will be used to better understand what types of animals are making the largest contribution to the problems at the beach.

As the program progresses, a clearer picture of the sources of the bacteria found on the beaches of RCC and ECC will emerge. When completed, a review will be conducted to evaluate appropriate protocols for addressing source identification in other watersheds.