Geology & Groundwater Quality

The Southern San Joaquin Valley is underlain by thousands of feet of sedimentary deposits. In the eastern portion of the bank, these sediments are about 14,000 feet thick. The upper portion of these sediments, which were deposited by the Kern River over hundreds of thousands of years onto an alluvual fan, form the groundwater basin in the Kern Water Bank area. These sediments consist mostly of sand and lesser amounts of gravel, silt and clay. The sand and gravel deposits are very well suited to the recharge, storage, and recovery of water.

The quality of the water stored in the Kern Water Bank is excellent. For example, the concentration of total dissolved solids (TDS) in our well water averages about 220 mg/l. The TDS in the California Aqueduct averages 240 mg/l and can range up to 325 mg/l. The recommended drinking water limit for TDS is 500 mg/l. The water from each well is thoroughly and regularly tested in accordance with protocols developed by the California Department of Health Services. These are the same tests conducted on the public’s drinking water supply.

In addition to testing each supply well, the Kern Water Bank regularly monitors groundwater conditions with a network of 57 dedicated monitoring wells. Water levels are measured at least semiannually, and the water is tested for the presence of several constituents annually. This monitoring will alert us to any detrimental changes in water quality. It should be noted that, with the exception of a few localized oilfield operations, there are no potential pollution sources on the Water Bank.