United States Geological Survey to Do Critical Water Study of Malibu Lagoon

• Research Will Occur Simultaneously with EPI Analysis

BY BILL KOENEKER

Malibu city officials are cheering what they are claiming is another benefit derived from the water quality symposium last April—a proposed water quality study by the United States Geological Survey to address “recurring water quality issues related to nutrients and fecal indicator bacteria in Malibu Lagoon and Surfrider Beach.”
“It was determined that the work could be done concurrently with ongoing epidemiological studies of fecal indicator bacteria exposure and human health effects along Malibu beaches that is being done by the Southern California Coastal Water Research Project,” wrote City Manager Jim Thorsen, in a memo to council members.
The city council agreed last week, without comment, to authorize Thorsen to execute a joint funding agreement between the city and the USGS for the $223,325 program with the municipality covering $183,325 of the cost and the USGS providing the remaining $40,000.
The acting director of the USGS California Water Science Center indicated that the study would include collection of chemical and isotopic data from special test wells.
Ten existing wells will be sampled for major ions, such as calcium, magnesium and sodium, selected trace elements, nutrients and the stable isotopes of oxygen and hydrogen. Salinity will be determined.
Water from selected wells in areas believed to be impacted by septic discharges also will be analyzed for nitrogen contaminants, and oxygen isotopic composition of the nitrate molecule.
“These data will be used to evaluate the source of nitrate contamination (human and animal sources versus chemical fertilizers). Water from selected wells also will be analyzed for selected tracers of fecal indicator bacteria contamination,” a USGS document states.
Direct-current resistivity surveys, will also be done. Results will be used to determine the thickness and lithology of alluvial deposits in the area.
Review of the existing data of fecal indicator bacteria collected by local agencies from streams, lagoon and near shore water in Malibu will be used for a data base. Also planned for study is the, groundwater exchange with near-shore ocean water. Measurements of groundwater discharge to Malibu Lagoon and collection of bacterial “source tracking” data will be gathered
“Data collected from this study will be analyzed to determine the suitably of techniques utilized in this study for determining the source of nutrients and FIB to Malibu Lagoon and near shore ocean water. Results will be presented in letter format to the City of Malibu at the end of the project,” wrote Eric Reichard, the acting director of USGS CSC.