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• Groundwater Analysis 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 (Plates 6 and 7). According to an analysis of these maps, the ground-water elevation ranges from 30 to 40 feet above mean sea level, depending on the season. The ground-water flow appears to vary significantly depending on season; in the spring, the flow direction and rate are unclear, while in the fall the flow is to the north-northwest at a rate of approximately 10 feet per mile. Given that the ground elevation of the Site is approximately 75 feet above sea level, based on the County ground water maps the depth to ground water below the Site is estimated to range between 105 to 115 feet. Potential Ground Water Contamination Issues The Nitrate Loading 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 and cattle ranches, 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 San Joaquin County Environmental Health Department's Water Well Data Table dated March 10, 2009 for nearby addresses that have been tested for nitrate and dibromochloropropane (DBCP). Four wells were identified at addresses within approximately three-quarters of a mile of the subject Site. Only one of the wells had been tested for DBCP; it was not detected in the sample. All the wells had been tested for nitrate; it was detected in all four samples at at concentrations of 20.0 to 62.0 mg/L-NO3. 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 µg/L. Based on the available information, it appears that several nearby wells have been exhibiting levels of nitrate in excess of the regulatory threshold. On-Site Wells One domestic well is currently located on the Site (Plate 2). Mr. Atwal plans to drill a new well to serve the proposed employee housing units. No well permits were identified for the Site from among the San Joaquin County Environmental Health Department permit files. • LOGE 1833 Page 3