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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 2018 and the spring of 2019 were the most recent available from this source. According to an analysis of these maps (Plates 4 and 5), ground water elevation near the Site is approximately 20 feet below mean sea level; the Site is just beyond the mapped area. Ground water appears to flow to the north in the general area; the rate could not be calculated because of the Site's location. Given that the ground elevation of the Site is approximately 46 to 47 feet above mean sea level, the depth to water below the Site is estimated to be approximately 26 to 27 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, six wells within a one -mile radius of the subject Site have been tested for nitrate. Nitrate was detected at a concentration between 0.1 and 5.0 mg/L-N in one of the wells, and at concentrations over 10 mg/L-N in the other five wells. According to the DBCP map, six wells within a one -mile radius of the Site have been tested for DBCP. DBCP was detected in two wells at concentrations between 0.01 and 0.2 ug/L, and in one well at a concentration over 0.2 ug/L; no DBCP was detected in the remaining three wells. On -Site Wells A domestic well is located on the Site (Plate 2). One well permit was identified for the Site from among the files of the San Joaquin County Environmental Health Department: • July 2003 permit for pump replacement at domestic well. This permit has been included in Appendix 4 of this report. LOGE 2234 Page 3