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ameO <br /> evenly among 14,000 residents, amounts to approximately 337 gallons per person per day. <br /> Much of the water is likely used for irrigation and other purposes, based on the seasonality of <br /> use and high per capita water consumption. <br /> A summary of pumping records for the years 2002 to 2007 is shown graphically in Figure 14 <br /> and summarized in Table 4. The operation of the wells is highly variable. Some wells are <br /> shutdown for several months, other wells are used more consistently (Figure 14). Municipal <br /> well MW-4 was used to supply drinking water until November 2002, when it was taken out of <br /> service. From 2002 to mid-2004, wells MW-10 and MW-12 provided most of the drinking water <br /> supply; well MW-13 replaced well MW-12 thereafter and this well currently provides most of <br /> the drinking water supply for the City of Ripon (with an average monthly production rate of <br /> 1152 gpm; Table 4). Municipal wells MW-10 and MW-12 were designed and constructed to <br /> extract water from the Intermediate and Lower Aquifer systems. Well MW-13 is constructed to <br /> pump entirely from the Lower Aquifer. Well MW-10 is the deepest drinking water well, with a <br /> total depth of 462 feet bgs; wells MW-12 and MW-13 are 334 and 450 feet deep, respectively. <br /> Wells MW-7 and MW-9 are also important wells for drinking water supply; these shallower <br /> wells pump from the Intermediate and Upper Aquifers to depths of 200 feet bgs (Table 4). <br /> Wells MW-5 and MW-11 are used to supply non-potable water for irrigation and other <br /> purposes. MW-11 is rarely used. In 2007, approximately 11% of the groundwater pumped was <br /> for non-potable use. <br /> Vertical flow profiling was conducted in well MW-12 while it was pumping at approximately <br /> 1,839 gpm in October 2005. The results of the profiling indicated that the majority of the flow <br /> was derived from the uppermost screened interval, where 53% of the total yield was from 160 <br /> and 185 feet bgs; yields of 26% were calculated for the 215 —235 feet bgs interval, 15% for <br /> the 265 — 285 feet bgs interval, and 6% for the interval from approximately 300 — 320 feet bgs; <br /> ECO:LOGIC, 2005b). The observed decrease in yield with depth may reflect the higher <br /> permeability of the younger, less compacted shallower sediments. <br /> Neenah Paper Company Industrial Supply Wells <br /> NP wells PW-6, PW-7, and PW-8 are located near the Stanislaus River where it is crossed by <br /> State Highway 99. These wells are pumped at combined average annual rates of <br /> approximately 860 gpm; the rates do not vary seasonally (pumping information was provided <br /> by Binayak Archarya of ECM; obtained from communication with Neenah Paper). The wells <br /> have multiple screened zones, with filter pack extending from 115 feet bgs to 210 feet bgs <br /> (PW-6 and PW-7) and from 100 — 260 feet bgs (PW-8) (Appendix D). Therefore, these wells <br /> draw water primarily from the Intermediate and Lower Aquifers. <br /> AMEC Geomatrix, Inc. <br /> I:\Doc_Safe\9000s\9837.005\4000 REGULATORY\SCM_01.30.09\1_text\SCM Report Final.doc 33 <br />