Bringing Water To a Thirsty Southland: : Complexity Behind the Scenes

photo by Lynne Plambeck

Most people living in Southern California turn on their taps, splash in their pools, and water their lawns without realizing that amazing efforts go into making their water available and plentiful. For an example of such efforts, look at the Castaic Lake Water Agency (CLWA), the wholesale water agency that provides water to the four water retailers serving the Santa Clarita Valley. The water sources are fascinating in their own right, but it is the acquiring, storing, treating, and distributing of all this water that makes CLWA's story so remarkable.

Annual demand for water in the Santa Clarita Valley is about 90,000 acre feet per year and growing. About 35,000 acre feet of the valley's demand is met from local underground aquifers: the Alluvial Aquifer beneath the Santa Clara River and its tributaries (requiring only shallow wells), and the Saugus Formation that underlies the Santa Clarita Valley (requiring deep wells). The retailers (one of which is owned by CLWA) extract and disinfect the groundwater, and pump it straight into the distribution system.

Local groundwater extracted by non-agency residential pumpers, agricultural operations, and the Los Angeles County Sheriff's 'Honor Farm' adds up to another 15,000 acre feet per year of groundwater extractions.

CLWA provides the remaining 40,000 acre feet of water needed by valley residents. Most of the water that CLWA directs to its four retailers comes from hundreds of miles away in Northern California via the State Water Project (SWP), and is stored primarily in Lake Oroville (in Butte County) and San Luis Reservoir (in Merced County).

CLWA has a contract with the California Department of Water Resources for 95,200 acre feet per year. In reality, for a number of reasons that have to do with annual precipitation and current reservoir capacities, to name a few, about 60% of that contract amount is available on average. CLWA's original SWP contract amount was for 41,500 acre feet per year. Because of growing population in the Santa Clarita, CLWA has over the years increased its supply of imported water. In the late 1980's, CLWA acquired 12,700 acre feet of SWP water from a water district in Kern and Kings Counties. More recently, a court ruling upheld the legality of a contract into which CLWA entered in 1999. This water-transfer contract 'perfected' CLWA's purchase of 41,000 acre feet of SWP water annually from the Wheeler Ridge Maricopa Water Storage District, a member agency of the Kern County Water Agency.

CLWA also executed a water acquisition agreement in 2007 with the Buena Vista Water Storage District and the Rosedale-Rio Bravo Water Storage District in Kern County. When the Kern River runs full (and certain other water becomes available), the excess water is captured and stored in Rosedale- Rio Bravo aquifers. This wateracquisition agreement gives CLWA 11,000 acre feet of water per year. Last but not least, CLWA supplies a small amount of recycled water to the valley. Realizing that water recycling is the one source of supply that CLWA can increase over time as it is needed with minimal or no impact to the environment, CLWA intends to invest heavily in recycling facilities in the years to come.

In order to 'firm up' the reliability of its SWP supply, CLWA is participating in two groundwater banking programs in Kern County. The purpose of the banking programs is to store excess SWP water in excess of the valley's needs. Then, in dry years or times of drought when SWP water availability is reduced, the stored water is withdrawn to supplement SWP water deliveries to the valley. One of the banking programs is with the Semitropic Water Storage District in Kern County, where CLWA has stored some 45,000 acre feet of SWP water underground. The other banking program is with the Rosedale-Rio Bravo Water Storage District, where CLWA has stored an additional 64,900 acre feet of SWP water (and has the right to store as much as 100,000 acre feet at any one time).

As an additional means of ensuring SWP supply reliability, CLWA is allowed to store up to 6,060 acre feet of SWP water in Castaic Lake (another SWP facility and 'terminal reservoir' from which CLWA takes delivery of its SWP water) by means of an arrangement called a flexible storage account. In those years in which CLWA withdraws part or all of these 6,060 acre feet of water, it must replace the withdrawn water within five years. CLWA manages this account by drawing on it only during dry periods (and paying it back with SWP water in years of abundant or normal rainfall). To sum it all up, CLWA and the four local water retailers have developed a 'water supply portfolio' that has essentially droughtproofed the Santa Clarita Valley. This portfolio consists of two groundwater aquifers, two imported sources of supply from different areas of the state, and recycled water, and is enhanced by the CLWA's water banking programs. Just like a sound personal investment portfolio, the valley's water supply portfolio is very diversified and thus provides a high degree of water supply reliability for valley residents and businesses. In fact, the Santa Clarita Valley's water utility reliability is among the highest of all utilities; when residents of the Santa Çlarita Valley turn on their taps, water flows 24/7. For all Southland residents, a complex story lies behind the source of their communities' water supplies - but just by itself, the CLWA story of effort and planning argues for valuing much more highly a wet, watery resource that we too often take for granted.