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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 2017 and the spring of 2018 were the most recent available from this source. The Site is just beyond the mapped area on both these maps (Plates 5 and 6); the nearest contours indicate a ground-water elevation of sea level. The ground-water flow direction could not be determined in the immediate vicinity of the Site, though in general ground water appears to flow toward the north. Given that the ground elevation of the Site is approximately 10 feet above mean sea level, the depth to water below the Site is estimated to be 10 feet or less. On March 26, 2021, Live Oak excavated a boring adjacent to the percolation test hole PB (discussed below) for the purpose of determining the depth to water. Ground water was encountered in the boring at 5.97 feet below ground surface. It is anticipated that water levels beneath the Site will fluctuate, especially on a seasonal basis, depending on pumping practices in the area. 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. A former poultry farm is located approximately 500 feet east of the Site. The other properties in the area are agricultural. 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 7 and 8). According to the nitrate map, seven wells within a two-mile radius of the subject Site have been tested for nitrate. Five of these wells were found to contain nitrate at concentrations between 0.1 and 5.0 mg/L, and one was found to contain nitrate at a concentration between 5.1 and 10.0 mg/L-N; no nitrate was detected in the final well. According to the DBCP map, four wells within a two-mile radius of the Site have been tested for DBCP. No DBCP was detected in any of the wells. The Maximum Contaminant Level (MCL) for nitrate is 10 mg/L-N; the MCL for DBCP is 0.2 [A.g/L. LOGE 2121 Page 3