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Ground Water Information Depth and Gradient Live Oak reviewed ground-water elevation information available from the San Joaquin County Flood Control and Water Conservation District to determine the ground water levels near the Site. Data from the fall of 2017 and the spring of 2018 were the most recent available from this source. According to an analysis of these maps (Plates 4 and 5), ground-water elevation is approximately 30 feet below mean sea level; the ground- water flow beneath the Site is to the east at a rate of approximately 6 to 15 feet per mile. Given that the ground elevation of the Site is approximately 55 to 60 feet above mean sea level, the depth to water below the Site is estimated to be approximately 85 to 90 feet. Potential Ground Water Contamination Issues The Soil Suitability Study is not intended to be an investigation into ground-water contamination sources, and no such investigation was conducted. Many sources can contribute to ground-water contamination, including leaking underground storage tanks, agricultural activities, dairies, septic systems, and storm water infiltration. Agricultural activities and the use of septic systems in the area are known ground-water contamination sources with the potential to impact the Site. Two common ground-water contaminants in San Joaquin County are nitrate and dibromochloropropane (DBCP). Live Oak reviewed the San Joaquin County Environmental Health Department's maps of Nitrate — Land Use Data and DBCP — Land Use Data dated February 20, 2019 (Plates 6 and 7). According to the nitrate map, five wells within a half-mile radius of the subject Site have been tested for nitrate; nitrate was detected in four of the wells at concentrations between 0.1 and 5.0 mg/L-N, and in the final well at a concentration between 5.0 and 10.0 mg/L-N. According to the DBCP map, five wells within a half-mile radius of the Site have been tested for DBCP. No DBCP was detected in four of the wells; it was detected at a concentration between 0.01 and 0.21Ag/L in the final well. On-Site Wells A domestic well is located on the Site. No well permits were identified for the Site from among the files of the San Joaquin County Environmental Health Department. LOGE 20-59 Page 3