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CONJUNCTIVE USE Another method ot improving overall water supply reliability is joint or "conjunctive use" of groundwater and surface water. This includes the use of treated and recycled wastewater and imported water for artificial groundwater recharge, water conservation programs and underground water banking. Under a conjunctive use program, surface water is relied on for irrigation, urban use and to recharge groundwater basins during wet years. The excess surface water is "banked" or stored in underground aquifers so it is WATER RECYCLING Recycling water so that it can be reused can extend water supplies, improve water quality, reduce the discharge and disposal costs of wastewater and save energy. Water recycling can be a basic or complex process depending on the end use of the water. Water treatment methods include the removal of sewage solids (primary effluent), oxidation and disinfection (secondary effluent), and coagulation. tiltration and disinfection (tertiary effluent). Potable water also has been achieved in some regions of the state using advanced treated recycled water. Technologies such as microfiltration and reverse osmosis are used in instances where recycled water is used as drinking water. Recycled water can be applied to agriculture and landscape irrigation, industrial recycling, and recharging groundwater. The treatment and reuse of municipal wastewater to irrigate fields, water golf courses or recharge groundwater basins increased during the 1980s. especially in southern California. Recycled water also can be used as a barrier to prevent seawater intrusion as is being done in Orange County. Some areas, like the San Gabriel Valley and the Bay Area, recycled water is used to SEA WATER DESALINATION The severe water shortages cities faced in 1991 caused a reevaluation of converting salt water into potable water - a process that previously had been considered too costly and complicated. By 1994. three coastal communities, Santa Barbara, Catalina Island and Morro Bay, had municipal desalination plants in operation while several others were contemplating the construction of desalination plants. Santa Barbara's desalination plant, which can produce 7,500 acre-teet of water a year at a cost ot available when surface water supplies are low. Storing water underground has several advantages over surface water storage. It is far less damaging to the environment than the construction of reservoirs and dams, and usually does not require an exten- sive distribution system. Water banked underground also has a much lower evaporation rate than surface reservoirs. Conjunctive use programs are being implemented by some local water districts and include the Kern Water Bank project. supplement the areas' drinking water. There are, however, constraints on water recycling projects and in particular use of recycled water for consump- tion, the most significant being cost and public perception. Recycled water is expected to play an increasingly important role in Calitornia. In 1995. the state recycled 450,000 acre-feet of water annually. That number is expected to swell to at least 1 million acre-feet annually by 2020. CALFED has established water recycling as a key component of its Water Use Efficiency Program and estimates it can reclaim between 225.000 to 310,000 of water through water recycling during Stage 1 of the program. And Proposition 13. the 52 billion water bond pas- sed in 2000, in- cludes 540 mil- lion for loans to be used strictly for water recy- cling programs. 51,100 dollars per acre-foot, was used only at the initial start up in 1992. Since that time, there has been sufficient surface water supply to meet demand and a portion of the Santa Barbara plant has been dismantled and sold to Saudi Arabia. However, should the need arise, the plant still can process 3,000 acre-feet ot water annually. This desalination pla1ll uses 1he re\'er.'i(' osmosis process 10 remo\'e salt from ~rlltl'r. 1J