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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 25 to 35 feet below mean sea level; the ground-water flow beneath the Site is to the northeast at a rate of approximately 8 to 10 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 80 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, 11 wells within a half-mile radius of the subject Site have been tested for nitrate, nitrate was detected in seven of the wells at concentrations between 0.1 and 5.0 mg/L-N, in two at concentrations between 5.0 and 10.0 mg/L-N, and in one at a concentration over 10 mg/L-N; no nitrate was detected in the final well. According to the DBCP map, nine wells within a half-mile radius of the Site have been tested for DBCP. No DBCP was detected in eight of the wells; it was detected at a concentration between 0.01 and 0.2 ug/L in the final well. On-Site Wells A domestic well is located on the Site. One well permit was identified for the Site from among the files of the San Joaquin County Environmental Health Department. The permit, dated October 1997, was for a new domestic well with an approximate depth of 215 feet. The permit notes that first water was encountered at 100 feet deep, and the grout seal was installed at that depth. The permit has been included in Appendix 4 of this report. LOGE 20-56 Page 3