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from this source. According to an analysis of these maps (Plates 5 and 6), ground water elevation is approximately 28 to 38 feet below mean sea level; ground water flows down to the northeast at a rate of approximately eight feet per mile. Given that the ground elevation of the Site is approximately 55 feet above mean sea level, the depth to water below the Site is estimated to be approximately 83 to 93 feet. San Joaquin County experienced its highest recent ground-water levels in 1983 and 1999. Review of ground-water maps for spring of these years (Plates 7 and 8) reveals that depth to water would have been approximately 70 to 75 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 9), six wells within a half-mile radius of the subject Site have been tested for nitrate. Nitrate was detected in four of these wells at concentrations between 0.1 and 5.0 mg/L-N, in one at a concentration between 5.1 and 10 mg/L-N, and in one at a concentration over 10 nng/L-N. According to the DBCP map (Plate 10), 11 wells within a one-mile radius of the Site were tested. DBCP was not detected in ten of those wells; it was detected in the one remaining well at a concentration between 0.01 and 0.2 ug/L. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate is 10 mg/L-N; the Ma_ for DBCP is 0.2 14g/L. On-Site Wells No wells are currently located on the Site. No well permits were identified for the Site from among the files of the San Joaquin County Environmental Health Department. Water Sample Because no well is present, no water sample was collected as part of this investigation. LOGE 1929 Page 3