Stormwater Engineering Projects

Picture of West Coast Basin Barrier

ANNOUNCEMENTS

  • Project presented at the Manhattan Beach City Council Meeting on 6/18/19
  • Project presented at the Hermosa Beach City Council Meeting on 7/23/19
  • Community Meeting held in the City of Hermosa Beach on 10/28/19
  • Community Meeting held in the City of Manhattan Beach on 11/6/19

BACKGROUND

The West Coast Basin Barrier Project (WCBBP) was designed and constructed in the early 1950's to prevent seawater from intruding into the underlying aquifers of the West Coast Groundwater Basin in the County of Los Angeles. The WCBBP is one of three seawater barriers that Public Works operates to prevent seawater from contaminating the groundwater by injecting freshwater to form a protective pressure ridge. Over five million residents of the Southern California Coastal Plain depend on this groundwater that provides up to 40 percent of the drinking water supply.

PROJECT SUMMARY

Public Works proposes to construct 11 injection wells and one monitoring well to replace and supplement existing WCBBP facilities located within the Cities of Manhattan Beach and Hermosa Beach. Nine injection wells will be constructed to replace existing injection wells that are beyond their useful life and require immediate replacement. Two new injection wells will be constructed at locations in-between existing injection wells along the WCBBP to increase the integrity of the barrier and provide increased protection against seawater intrusion. Prior to constructing the new wells, the existing injection wells will be properly sealed to prevent the possibility of subsidence and/or groundwater cross contamination. Once the new injection wells are brought online, they will help prevent seawater intrusion by creating a freshwater pressure ridge in the underlying aquifers of the West Coast Basin located in the County of Los Angeles. The new observation well facility will increase Public Works' ability to monitor groundwater elevations and chloride concentrations for the region's underground aquifers and will improve overall operational efficiency of the WCBBP.

Construction is currently planned to start February 2021 and finish February 2022.

PROJECT DETAILS

CONTACTS

For more information on the project please contact swb@dpw.lacounty.gov

Updated on: 07/01/2020