PUB00022 - Laserfiche WebLink

Home Browse Search

Groundwater For more than a century, groundwater has supplied a major part of California's water needs - about on8- third ot the water supply in normal years and up to two-thirds in critically dry years. Although the state's surface and groundwater have been treated as separate resources they are intimately connected. Precipitation seeps into the earth to become ground. water, later resurfacing in a spring, river, or spring- fed lake. Hydrologists estimate that as much as 30 percent of the water found in lakes or streams comes from groundwater. The use, transfer or contamina- tion of one can directly affect the other. The Golden State uses more groundwater than any other state - approximately 15 million acre feet in normal years. Additionally, groundwater is the sole source of drinking water for many cities. Unlike most other Western states, however, California has no statewide management program or permit procedure to regulate groundwater appropriations. Appropria- tive procedures developed for suriace water apply only to groundwater flowing through known and definite channels. But the bulk of California's vast groundwater resource - percolating groundwater- is not covered by these regulations. Generally, Californians use more groundwater than is replaced naturally or artificially. Artificial recharge involves using imported suriace water to recharge underground basins programs. Annual statewide overdraft - the amount that long term extraction exceeds long term supply - is estimated by DWR to decrease from 1.5 million acre-feet in 1995 to about 1.1 million acre-feet in 2020. Problems associated with overdrafted basins include lower water tables and increased energy costs for pumping, land sub- sidence, dry wells, contamination from sea water intrusion or toxic contaminants, and reduction in storage capacity of some basins. Although there are no statewide regulations govern- ing groundwater use, general parameters are provided by a number of judicial decisions. Until the early 1900s, California followed the English system that essentially allowed unregulated groundwater pumping. In 1903, the State Supreme Court in Katz v. Walkinson decided that given the state's arid climate, a rule of reasonable use should be applied to groundwater extractions. The Katz decision also held that property owners above a common aquifer have a shared right to fhe reasonable use of the groundwater below. Subsequently, courts established that groundwater may be appropriated by pumping and transported for use on land beyond the bound- aries of the aquifer. A groundwater user's right is likely to go undisturbed unless challenged by a com pet- ing user in court or unless government intervenes in response to problems resulting from that use, such as land subsidence or contamination of an aquifer. Today, groundwater withdrawals are regulated only on a limited basis including where 1) a groundwater basin has been adjudicated. establishing the rights of various parties; 2) the Legislature has granted a local water district power to monitor or regulate use or levy a "pump tax;" 3) groundwater management districts or counties have adopted relevant ordinances; 4) the water agencies in an area have agreed to self-regulation. Attempts over the years to adopt statewide ground- water regulations have been vigorously opposed by overlying land owners, particularly agriculture inter- ests and local water districts. At the local level there has been movement to control groundwater pump- ing. Under state legislation passed in 1992, local entities may voluntarily develop groundwater management plans in unregulated basins. In 1994, a state appellate court upheld the authorily of cities and counties to regulate groundwater use. Currently, water users throughout California are awaiting action by the State Water Resource Control Board (State Board) n the governing body regulat- ing weter quality and suriace water rights for the state -- regarding the definition of water in two basins along the San Luis Rey River in northern San Diego County. The proposed decision states that all water in Pauma and Pala basins is part of "subterranean streams flowing through known and definite channels." If adopted by the State Water Board. the underground water in Pauma and Pala Valleys would no longer be defined as "percolating groundwater," but would be defined as suriace water subject to the jurisdiction of the State Board. Such a change would mean that each pumper's rights to groundwater in the basin would be quantified. Though many of the well owners may be able to continue extracting groundwater as a holder of a riparian water right, the proposed decision has raised some concerns among state groundwater users. Groundwater was once considered safe from pollution. It was believed that as surface water percolated into the ground. the soil would filter out contaminants. However, with the continued use and disposal of toxic chemicals and the development of increasingly sophisticated detection equipment, traces of industrial solvents and pesticides have been discovered in groundwater supplies throughout California. All of the state's groundwater basins are contaminated to some degree, according to DWR. 1 ~"~ .""'-..... .. ~ .. California llses more Mrowu!iwller lhan ml\' olher stale - on Cl\'erage J 5 millioll acre-feel anl/lwlly. Growu!\wller accOIl1ltsfor 30 perce1l1 of the Slale's supply il/ a norma/lI.arer year alld up 10 60 percl'1ll ill dry years. 15