SR0080784 SSNL - Laserfiche WebLink

Home Browse Search

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 spring and fall of 2016 were the most recent available from this source. The Site is located just west of the studied area on the maps, but the ground-water elevations can be extrapolated from the area to the east. According to an analysis of these maps (Plates 5 and 6), ground water elevation is approximately 40 feet above mean sea level; ground water flows toward the northeast or southeast at a rate of approximately seven to 13 feet per mile in the vicinity of the Site, depending on the season. Given that the ground elevation of the Site is approximately 240 to 280 feet, the depth to water below the Site is estimated to be 200 to 240 feet, depending on the location on the Site. 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 known leaking underground storage tank facility is located at the service station to the north of the subject Site, across Patterson Pass Road. Contaminated soil was noted after the removal of underground storage tanks in 1987 and 1990. Based on a 2018 report by Arcadis, ground-water contaminated with fuel and related additives has migrated south from the facility onto the northern portion of APN 209-100-24. The report indicates that the contaminant plume appears to be attenuating naturally; no evidence was identified to indicate that the subject Site located on the southern portion of the parcel has been impacted at this time. 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. Only one well was identified within approximately two miles of the Site. Nitrate was detected in the well at a concentration of 13.0 mg/L-NO3; the well had not been tested for DBCP. The Maximum Contaminant Level (MCL) set by the US EPA for nitrate as NO3 is 45 mg/L (10 mg/L-N); the MCL for DBCP is 0.2 ug/L. LOGE 1849 Page 3