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' K L E I N F E L D E R <br /> ' 5 SEMI-ANNUAL RESULTS AND DISCUSSION <br /> ' The results of the second semi-annual 2007 groundwater monitoring event conducted <br /> at the former Spreckles Site are discussed in the following sections. A discussion of <br /> the results and historical trends is included. <br /> ' 5.1. WATER LEVELS <br /> ' The depth to groundwater during the October 17 and 18, 2007 sampling event ranged <br /> from 16.04 to 23.12 feet below the top of the well casings (BTOC) in monitoring wells <br /> MW-1r and MW-26, respectively. The groundwater elevations on the sampling date <br /> ' ranged from 18.38 feet (MW-6r) to 26.23 feet (MW-5). A groundwater gradient and <br /> direction for the sampling event was calculated based on depth-to-water data collected <br /> from these wells and using survey data by RLC Associates conducted in December <br /> 1996, and subsequently supplemented by MCR Engineering. Based upon the <br /> groundwater elevations, the groundwater flow direction was estimated to be toward the <br /> north/northwest with an approximate gradient of 0.002 ft/ft. A relative flattening of the <br /> gradient was noted in the northwest area of the site. Groundwater elevations and flow <br /> directions may fluctuate significantly due to rainfall, groundwater recharge, groundwater <br /> pumping, etc. Therefore, changes in groundwater gradient may vary at this site with <br /> time. However, Kleinfelder's historical data suggests a generally consistent groundwater <br /> flow direction and gradient. <br /> ' Chart 1 is a graph comparing historical groundwater elevations in MW-5 (upgradient of <br /> the Spreckels site, east of Highway 99) and MW-1/MW-1r (on site at the downgradient <br /> edge of the former lime pond location). <br /> 5.2. LABORATORY ANALYTICAL RESULTS <br /> ' The following is a list of the reported ranges detected by the laboratory for specific <br /> analytes in groundwater samples obtained from the seven wells: <br /> pH [7.5 to 7.98] <br /> • Total Dissolved Solids (TDS) [420 to 1,400 mg/11 <br /> ' . Bicarbonate [160 to 730 mg/1] <br /> • Carbonate [ND (<5 mg/1)] <br /> • Hydroxide Alkalinity [ND (<5 mg/1)] <br /> Chloride (CI) [38 to 170 mg/11 <br /> • Nitrate as N [0.97 to 20 mg/1] <br /> ' • Sulfate 126 to 150 mg/1] <br /> • Specific Conductivity (EC) [590 to 2,000 µmhos/cm] <br /> • Calcium [56 to 190 mg/1] <br /> ' Sodium [29 to 130 mg/1] <br /> 20-3978-03.MN71ST08R117 February 1,2008 <br /> 0 2008 Kleinfelder Page 13 of 19 <br />