Groundwater Contamination Characterization Project

Groundwater Contamination Characterization Project

The project is primarily located in the southern portion of the City along U.S. Highway 101 (U.S. 101) between Prado Road and Los Osos Valley Road within Assessor’s Parcel Numbers 053-051-045, 053-052-045, 053-131-013, 053-141-012, 053-152-006, 053-152-008, 053-153-014, and 053-153-008. The approximately 30.4-acre project area encompasses 1) a 22-acre site for two groundwater extraction and treatment wells, water conveyance pipelines, and associated infrastructure, and 2) up to 12 potential monitoring well locations within the city with a 100-foot surrounding buffer accounting for the remaining 8.4 acres. Within the 22-acre site, the project includes two buildings (approximately 650 and 250-square feet each) to house extraction wells and equipment, a centralized treatment system (treatment pad with granulated activated carbon vessels and bag filters, as well as two backwash storage tanks), a new 6-inch sewer line connecting the backwash storage tank to the City’s sanitary sewer system, a new 12-inch water line connecting the treatment infrastructure to the City’s water distribution system, a new gravel access road, security fencing, the removal of seven trees to accommodate necessary pipeline infrastructure, and compensatory tree planting (minimum 1:1 ratio). The purpose of the project is to clean-up and prevent PCE (tetrachloroethylene) contamination in drinking water supply wells in the San Luis Valley Subarea of the San Luis Obispo Valley Groundwater Basin and to expand local water supply resiliency and reduce reliance on local surface water supplies. The project includes 12 possible monitoring well locations and one 22-acre site for two proposed extraction treatment wells, water distribution line, and associated structural and pipeline infrastructure. The 12 monitoring well locations, water conveyance pipelines, and the 22-acre treatment well site collectively represent the project site. In support of these goals, the City of San Luis Obispo proposes to install a network of monitoring wells and two treatment wells with associated utility infrastructure and a treatment system to monitor water levels and quality in the Subarea of the Basin, further characterize the PCE plume, and monitor the effectiveness of removing PCE impacted groundwater from the Subarea of the Basin. Funding for the implementation phase of the project includes California State Water Resources Control Board (SWRCB) Proposition 1 Groundwater Grant Program Agreement No. D2312550.

San Luis Obispo

San Luis Obispo

Northern California

California Air Resources Board (ARB), California Department of Conservation (DOC), California Department of Fish and Wildlife, Central Region 4 (CDFW), California Department of Parks and Recreation, California Department of Toxic Substances Control (DTSC), California Department of Transportation, District 5 (DOT), California Department of Water Resources (DWR), California Governor's Office of Emergency Services (OES), California Highway Patrol (CHP), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Public Utilities Commission (CPUC), California Regional Water Quality Control Board, Central Coast Region 3 (RWQCB), Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Drinking Water, District 6, State Water Resources Control Board, Division of Water Rights, State Water Resources Control Board, Divison of Financial Assistance

Other (2 extraction/treatment wells 12 monitoring wells &infrastructure)

Site Plan, Capital Improvement Project - Groundwater Extraction, Clean-up, and Monitoring

Aesthetics, Air Quality, Biological Resources, Cultural Resources, Geology/Soils, Mandatory Findings of Significance, Noise, Tribal Cultural Resources