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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 spring and fall of 2016 were the most recent available from this source. According to an analysis of these maps (Plates 5 and 6), ground water elevation is approximately 0 to 10 feet below mean sea level; the ground- water gradient could not be determined in the vicinity of the Site. Given that the ground elevation of the Site is approximately 30 to 34 feet, the depth to water below the Site is estimated to be 30 to 44 feet, depending on the season. 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 beyond those items discussion below. 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. Live Oak reviewed the EHD's Water Well Data Table dated March 10, 2009 for nearby addresses that have been tested for nitrate and dibromochloropropane (DBCP), common ground-water contaminants in San Joaquin County. Seven wells were identified within approximately one mile of the Site. Only one of the wells had been tested for nitrate as NO3.1 that constituent was detected at a concentration of 13.7 mg/L. All seven wells had been tested for DBCP; it was detected in all but one of the wells, at concentrations ranging from 0.06 to 3.4 ug/L. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate as NO3 is 45 mg/L (equivalent to 10 mg/L-N); the MCL for DBCP is 0.2 ug/L. Based on the data reviewed, it appears that much of the nearby ground water contains DBCP at levels above the MCL. On-Site Wells A domestic well and an irrigation well are located on the Site (Plate 3). No well permits were identified for the Site among the San Joaquin County Environmental Health Department files. • LOGE 1841 Page 3