Santa Ana Regional Water Quality Control Board, SARWQCB Project 332016-41, 8 pp, 17 Jul 2017

In this letter, the Santa Ana RWQCB certified and defined the conditions for a project to construct a biobarrier treatment system to remove perchlorate from contaminated groundwater in Laborde Canyon, which will prevent the perchlorate-contaminated groundwater from migrating off site and flowing into the San Jacinto River and San Jacinto Groundwater Basin. Three types of material—limestone gravel, wood chips, and a long-acting carbon substrate—will be emplaced upon excavation of a trench measuring ~280 ft in length and a minimum depth of ~29 ft measured at canyon center. Biobarrier operation and maintenance will include replenishment of the organic carbon substrate when geochemical and chemical sampling data indicate that the carbon is limiting perchlorate biodegradation. Injection ports installed during biobarrier construction will be used to inject diluted long-acting carbon substrate directly into the biobarrier or to extract groundwater from one port while the groundwater is simultaneously injected into adjacent ports to recirculate diluted carbon substrate within the barrier. https://www.waterboards.ca.gov/santaana/water_issues/programs/401_certification/docs/wqc/2017/Lockheed_Martin_Beaumont_Site_2_Laborde_Canyon_Remediation.pdf