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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. According to an analysis of these maps (Plates 5 and 6), ground water elevation is approximately 5 to 25 feet below mean sea level. Ground water appears to flow to the east-southeast at a rate of approximately 11 to 21 feet per mile. Given that the ground elevation of the Site is approximately 130 to 140 feet above mean sea level, the depth to water below the Site is estimated to be approximately 135 to 165 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 7 and 8). According to the nitrate map, eight wells within a one-mile radius of the subject Site have been tested for nitrate. Seven of these wells were found to contain nitrate at concentrations between 0.1 and 5.0 mg/L; nitrate was detected in the final well at a concentration over 10 mg/L-N. According to the DBCP map, at six wells within a one-mile radius of the Site have been tested for DBCP. DBCP was not detected in five of these wells; it was detected in the final well at a concentration between 0.01 and 0.2 A/L. The US EPA has set the Maximum Contaminant Level (MCL) for nitrate at 10 mg/L-N. The US EPA set the MCL for DBCP at 0.2 parts per billion (ppb, equivalent to !Ag/L) because it believes that given present technology and resources, this is the lowest level to which water systems can reasonably be required to remove this contaminant should it occur in drinking water. The Maximum Contaminant Level Goal (MCLG) for DBCP is zero. LOGE 2114 Page 3