The District operates potable, non-potable, and recycled water supply systems in southern Ventura County, California. The District's service area encompasses approximately 31 square miles. The potable water system serves roughly 32,000 people and delivers approximately 15,000 acre-feet of water each year through more than 8,500 service connections in portions of the cities of Camarillo, Moorpark, and Thousand Oaks and unincorporated Ventura County. The District's potable water system is regulated by the State Water Resources Control Board (SWRCB), Division of Drinking Water (DDW) as a community water system. In 2018, the State Water Board implemented a new maximum contaminant limit (MCL) for 1,2,3-
Trichlorpropane (TCP), a synthetic organic compound that was an impurity in certain soil fumigants used in agriculture, of 5 ppt. Upon testing, it was discovered above the MCL in three of the wellfield's four wells, which were promptly removed from service. The fourth well was taken offline in early 2020. After an initial, ultimately unsuccessful attempt to resolve the TCP issue with blending, which turned out to be an ineffective strategy due to the very low MCL for TCP and the District’s inability to meet its blend plan objectives, CWD is now constructing a granular activated carbon (GAC) treatment plant to treat for the TCP. The plant is expected to be completed in 2022.
The wellfield will remain off until that time. The District has decided to move forward with a centralized 2,350-gallons per minute (gpm) GAC treatment plant to remove TCP from the Conejo 2, Conejo 3, Conejo 4, and the Santa Rosa 8 wells so that the wells can be returned to service. The existing facility is approximately 0.5 acres, and the proposed new facilities would be approximately 2.5 acres. Specific Project components include:
• Three pairs of GAC vessels (six total), expandable to five pairs of vessels in the future: 12-foot diameter; 18-foot tall; placed on a concrete foundation of 3,500 square feet;
• Excavations for the foundation and infrastructure would occur up to approximately 5 feet in depth; • Backwash equalization tank: 126,000 gallons; 33 feet in diameter; 24 feet tall; ring wall footing;
• Treated water storage tank: 85,000 gallons; 27 feet in diameter; 24 feet tall; ring wall
• Well pump replacements (four total): two 100 horsepower (hp) and two 125 hp;
• Electrical service upgrade - to allow higher horsepower well pumps and non-potable
pumps to operate;
• Fixed standby generator; which will include an approximately 10,000-gallon diesel fuel tank for storage;
• Chemical feed systems: One 5,000-gallon sodium hydroxide storage tank and feed
system and one 14-ton carbon dioxide feed system;
• One small diameter pipeline and electrical conduit between this main site and the existing Santa Rosa 8 well building to the south;
• Piping, fittings, valves, and associated infrastructure;
• Backwash (non-potable water) pumps: two 75 hp pumps;
• Chain link fence: 8-feet tall with three strands of barbed wire; approximately 1 ,000 linear feet; and a new access gate off of Hill Canyon Road; and
• Site surfacing of ag base under crushed rock; asphalt paved driveway with concrete pads at the offloading area for delivery trucks.
• Total site improvements area; « 108,000 square feet.