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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 spring and fall of 2016 were the most recent available from this source. According to an analysis of these maps (Plates 4 and 5), ground water elevation is approximately five feet below to 20 feet above mean sea level; the ground-water flow beneath the Site is to the north or northwest at a rate of approximately 18 to 21 feet per mile. Given that the ground elevation of the Site is approximately 135 to 140 feet above mean sea level, the depth to water below the Site is estimated to be approximately 115 to 145 feet. San Joaquin County experienced its highest recent ground-water levels in 1983 and 1999. Maps of ground-water levels were reviewed for this study (San Joaquin County Flood Control and Water Conservation District, 1983 and 1999); however, the vicinity of the Site was not mapped during these years. 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. According to the maps (Plate 6 and 7), four wells within a half-mile radius of the subject Site have been tested for nitrate; it was detected in one at a concentration between 5.1 and 10.0 mg/L-N, and in the other three at a concentration greater than 10.0 mg/L-N. Two wells within one-half mile of the Site were tested for DBCP; no DBCP was detected in either well. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate is 10 mg/L-N; the MCL for DBCP is 0.2 µg/L. LOGE 1914 Page 3