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Ground Water Information <br /> Depth and Gradient <br /> Live Oak reviewed ground water elevation information available from the San Joaquin <br /> County Flood Control and Water Conservation District to determine the ground water <br /> levels near the Site. Data from spring and fall of 2016 were the most recent available <br /> from this source. According to an analysis of these maps (Plates 4 and 5), ground <br /> water elevation is approximately 60 to 63 feet below mean sea level; the ground-water <br /> flow beneath the Site is to the east at a rate of approximately 9 to 11 feet per mile. <br /> Given that the ground elevation of the Site is approximately 36 to 37 feet above mean <br /> sea level, the depth to water below the Site is estimated to be approximately 96 to 100 <br /> feet. <br /> San Joaquin County experienced its highest recent ground-water levels in 1983 and <br /> 1999 (Plates 6 and 7). Based on review of maps of ground-water levels for spring of <br /> those years, depth to water was approximately 65 to 70 feet (San Joaquin County Flood <br /> Control and Water Conservation District, 1983 and 1999). <br /> Potential Ground Water Contamination Issues <br /> The Soil Suitability Study is not intended to be an investigation into ground-water <br /> contamination sources, and no such investigation was conducted. Many sources can <br /> contribute to ground water contamination, including leaking underground storage tanks, <br /> agricultural activities, dairies, septic systems, and storm water infiltration. Agricultural <br /> activities and the use of septic systems in the area are known ground water <br /> contamination sources with the potential to impact the Site. <br /> Two common ground-water contaminants in San Joaquin County are nitrate and <br /> dibromochloropropane (DBCP). Live Oak reviewed the San Joaquin County <br /> Environmental Health Department's maps of Nitrate — Land Use Data and DBCP— Land <br /> Use Data dated February 20, 2019. According to the nitrate map (Plate 8), one well <br /> within a half-mile radius of the subject Site has been tested for nitrate; it was detected in <br /> the tested well at a concentration between 0.1 and 5.0 mg/L-N. One well within one-half <br /> mile of the Site has been tested for DBCP (Plate 9); DBCP was detected in the tested <br /> well at a concentration between 0.01 and 0.2 ug /L. The Maximum Contaminant Level <br /> (MCL) set by the US EPA for nitrate is 10 mg/L-N; the MCL for DBCP is 0.2 ug/L. <br /> LOGE 20-10 Page 3 <br />