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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 5 and 6), ground water elevation is approximately 42 to 48 feet below mean sea level; the ground-water flow beneath the Site is to the southwest at a rate of approximately 7 feet per mile in the spring, and to the north at a rate of approximately 6 feet per mile in the fall. Given that the ground elevation of the Site is approximately 87 feet above mean sea level, the depth to water below the Site is estimated to be approximately 129 to 135 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. According to the nitrate map (Plate 7), six wells within a half-mile radius of the subject Site have been tested for nitrate, nitrate was detected in five of the wells at concentrations between 0.1 and 5.0 mg/L-N, and in the sixth well at a concentration between 5.1 and 10.0 mg/L-N. Six wells within one-half mile of the Site have been tested for DBCP (Plate 8); DBCP was detected in one well at a concentration between 0.01 and 0.2 ug /L, and was not detected in the remaining five wells. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate is 10 mg/L-N; the MCL for DBCP is 0.2 ug/L. On-Site Wells A domestic well and an irrigation well are currently located on the Site. The domestic well has just been completed and is not yet operable, however. Three well permits were identified for the Site from among the files of the San Joaquin County Environmental Health Department: • June 1972 permit for pump repair at domestic well. The well was located within a cluster of structures that have since been removed from the Site. LOGE 20-27 Page 3