Walnut Creek Water Treatment Plant Pretreatment Project

Walnut Creek Water Treatment Plant Pretreatment Project

The Walnut Creek Water Treatment Plant (WTP), located at 2201 Larkey Lane, Walnut Creek, is the primary water supply for approximately 225,000 people in the District’s East-of-Hills service area, which includes portions of Pleasant Hill, portions of Walnut Creek, Alamo, Lafayette, Danville, Blackhawk, and San Ramon Valley communities. The Walnut Creek WTP treats Mokelumne River water stored in the Sierra foothills at Pardee Reservoir and water stored locally in Briones Reservoir. The Walnut Creek WTP lacks pretreatment and ozone facilities that limit its ability to treat water from the Sacramento River or other water transfers via the Freeport Regional Water Project facility (Freeport) and from neighboring water agencies via interties during planned and unplanned outages, as well as during droughts. The Walnut Creek WTP Pretreatment Project (Project) would add pretreatment facilities to the Walnut Creek WTP to more reliably treat a broader range of untreated Pardee and Briones water resulting from high rainfall runoff, wildfires, algae blooms, climate change, improve the ability to treat supplemental supplies from Freeport or the interties during planned and unplanned outages and droughts, and improve treated water taste and odor by removing organics and by adding ozone treatment. The Project would increase the Walnut Creek WTP capacity to meet planned future demands, improve water system reliability and operational flexibility, and allow for the potential decommissioning of the Lafayette WTP. Hydraulic changes at the Walnut Creek WTP would require modification of weir structures at the Lafayette WTP, located at 3848 Mt. Diablo Boulevard in Lafayette.

Lafayette, Walnut Creek

Contra Costa

San Francisco Bay Area

California Air Resources Board (ARB), California Department of Conservation (DOC), California Department of Fish and Wildlife, Bay Delta Region 3 (CDFW), California Department of Forestry and Fire Protection (CAL FIRE), California Department of Parks and Recreation, California Department of Transportation, District 4 (DOT), California Department of Water Resources (DWR), California Energy Commission, 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, San Francisco Bay Region 2 (RWQCB), California State Lands Commission (SLC), Delta Protection Commission, Delta Stewardship Council, Department of Toxic Substances Control, Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Drinking Water, District 4, State Water Resources Control Board, Division of Water Quality, State Water Resources Control Board, Divison of Financial Assistance

Water Facilities (Existing Water Treatment Plant)(Type Pretreatment, MGD 160)

NA

Aesthetics, Air Quality, Biological Resources, Cultural Resources, Cumulative Effects, Drainage/Absorption, Energy, Flood Plain/Flooding, Geology/Soils, Greenhouse Gas Emissions, Growth Inducement, Hazards & Hazardous Materials, Hydrology/Water Quality, Land Use/Planning, Mandatory Findings of Significance, Noise, Recreation, Transportation, Tribal Cultural Resources, Utilities/Service Systems, Vegetation, Wetland/Riparian, Wildfire