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california Water Today 77 <br />Water Sources: Local, Imported, Mined, and Reused <br />California supplements water supplies available from in-state precipitation <br />with imports from other states, groundwater mining, and some recovery of <br />wastewater and brackish water following intensive treatment. In addition, <br />available water supplies exceed the amounts flowing into the state because of <br />natural reuse, as excess irrigation water (the amount not consumed by crops) <br />and treated urban wastewater become available for use by others after being <br />returned to streams (Box 2.1). <br />Figure 2.4 shows the relative importance of these sources in total usable sup- <br />plies for agricultural, environmental, and urban uses. Overall, more than 80 per- <br />cent of the initial total (before reuse) is derived from local and out-of-state streams: <br />Three-quarters of these surface flows are from local projects and diversions <br />and roughly one-quarter are from the state and federal projects. About 18 per- <br />cent of the initial total is supplied by groundwater. Natural reuse constitutes <br />roughly one-quarter of gross supplies (almost half of all groundwater pumping <br />Figure 2.4 <br />California employs a diverse portfolio of water sources for agricultural, <br />environmental, and urban water uses <br />sOURcE: california department of Water Resources (2009). <br />NOTEs: The figure shows sources of gross water supplies, 1998–2005 average. Total water supply is <br />83 maf per year. Total does not sum to 100 percent because of rounding. sWP = state Water Project. <br />cVP = central Valley Project. <br />Local surface <br />water deliveries <br />(45%) <br />Local imported <br />deliveries <br />(1%) <br />CVP <br />deliveries <br />(9%) <br />Other <br />federal <br />deliveries <br />(1%) <br />SWP deliveries <br />(3%) <br />Reused <br />surface water <br />(17%) <br />Net groundwater <br />withdrawal <br />(10%) <br />Groundwater recharge <br />(8%)Recycled water <br />(0.3%) <br />Colorado <br />River <br />deliveries <br />(6%)