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Table 5-1: Average Annual Precipitation, Evapotranspiration and rrigatlon Demands <br />Month <br />ETo (In)' <br />Average Total <br />Precipitation (in) <br />Irrigation Demand (In)' <br />January <br />0.82 <br />2.91 <br />0.0 <br />February <br />1.47 <br />2.57 <br />0.0 <br />March <br />2.92 <br />2.12 <br />0.9 <br />April <br />4.4 <br />1.12 <br />3.8 <br />May <br />5.57 <br />0.44 <br />6.0 <br />June <br />6.86 <br />0.1 <br />7.7 <br />July <br />7.4 <br />0.02 <br />8.6 <br />August <br />6.35 <br />0.05 <br />7.4 <br />September <br />4.73 <br />0.16 <br />5.3 <br />October <br />3.34 <br />0.7 <br />3.1 <br />November <br />1.54 <br />1.72 <br />0.0 <br />December <br />1.01 <br />2.63 <br />0.0 <br />Annual <br />46.21 <br />14.54 <br />42.8 (3.56 ac -Macre) <br />Note: <br />a. CIMIS Station 191. <br />b. Western Regional Clknats Center. <br />c. 5 percent leaching fraction and 90 percent distribution uniformity. <br />City of Pleasanton <br />Final Water Supply Assessment <br />Stoneridgee Drive Specific Plan Amendment and Staples Ranch Project <br />4.0 Water Agency Background <br />5.3.2 Supply Sources <br />Zone 7 has three main sources of water. State Water Project (SWP) water via the South Bay <br />Aqueduct (SBA), surface runoff collected in the Lake Del Valle Reservoir, and groundwater. SWP <br />surface water makes up the bulk of the regional water supplies conveyed by Zone 7 to its retail <br />customers. These sources combined supply nearly all of the water to the cities of Dublin, Livermore, <br />and Pleasanton. <br />5.3.3 Zone 7 Water Supplies <br />Zone 7's three main sources of water supply are divided into five subcategories: 1) the Livermore <br />Amador Valley Groundwater Basin; 2) Out -of -Basin water storage options); 3) contracted SWP <br />supplies; 4) water through Lake Del Valle system; and 5) recycled water. The following discussions <br />present the planned and existing uses of each category. <br />5.3.4 Local Groundwater <br />5.3.4.1. The Uvennore- Amador Valley Groundwater Basin <br />The Livermore Amador Valley Groundwater Basin (LAVGB) is in the heart of the Livermore Valley, <br />extends south into the hills south of Pleasanton and Livermore. Figure 6 presents groundwater <br />basin information and well locations. It includes 65,000 acres occupied by both the Livermore Valley <br />(42,000 acres) and the Livermore Uplands (23,000 acres). A major portion of the LAVGB is the <br />Main Groundwater Basin (Main Basin), which covers an area of over 17,000 acres and has the <br />highest yielding aquifers and best quality water. The DWR Bulletin 118 has not identified the Main <br />Basin (DWR Basin No. 2 -10) in an overdraft condition or a basin expected to be in overdraft in the <br />8 The municipal retailers supplement their Zone 7 supplies by pumping their GPO from the Main Basin; the safe <br />yield from natural recharge of the Main Basin is calculated at 13,400 AFA <br />9 Zone 7 Water Agency Groundwater Management Plan, 2005, page 3-4. <br />P1Rojs WP oW6w11d2A1 suplaa Ranch,N61NFY&FIndW$Adoo <br />5-6 <br />