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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 2011 were-hhe�nost rece� �. available from this source. According to an analysis of-these m8ps_(Flates 5 and 6),\ ground water elevation ranges from approximately 42 to 53 feet above mean sea levet-" ground water flows down to the north at a rate of approximately seven to 14 feet per mile in the vicinity of the Site. Given that the ground elevation of the Site is approximately 60 to 75 feet, based on the County group ater riui _the depth to ground water below the Site is estimated to range between 18 to 22 feef;,,depending on the location on the Site. os°y " 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. Known ground-water contamination exists in the area as a result of activities at the Tracy Defense Depot, Olin Chlor Alkali facility, former Chevron Lyoth Loading Station, and former Old Valley Pipeline (a crude oil pipeline running along the railroad tracks that define the southwest property line of the Site) and other co-located pipelines. As discussed in the Surface & Subsurface Contamination Report (Live Oak, 2013), ground- water monitoring wells located on the Site have been found to contain levels of carbon tetrachloride, chloroform, sodium, chloride, nitrate, and total dissolved solids that exceed the Regional Water Quality Control Boards's Water Quality Goals. The source of these contaminants is the Olin Chlor Alkali facility, a bleach manufacturer located adjacent to the west of 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). Four nearby wells were identified at addresses located within approximately one-quarter mile of the Site. DBCP was not detected in any of the wells. Nitrate as NO3 was detected in all four wells at concentrations of 26 to 38 parts per million (ppm). The Maximum Contaminant Level (MCL) set by the US EPA for nitrate as NO3 is 45 ppm. LOGE 1223 Page 3