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June 14,2005 NOA Project Number: E05034A 4.0 GROUND WATER INFORMATION / 4.1 Ground Water Depth and Gradient [F The San Joaquin County Flood Control and Water Conservation District (1998 and 1999) ground water depth and elevation maps were reviewed to determine the ground water levels near the Site. The Fall 1998 and Spring 1999 maps are the most current official maps available from the County. According to these maps (Plates 3-6), ground water lies between 90 and 120 feet below ground surface and flows at a gradient of about 20 feet per mile to the east in the vicinity of the Site. No ground water was encountered by the staff of Neal O.Anderson&Associates, Inc. during the drilling of four percolation test holes to a depth of 25 feet on May 27, 2005,May 31, 2005 or June 6, 2005. ✓4.2 Potential Ground Water Contamination Issues Identifying potential ground-water contamination sources was not part of the scope of work for the soil suitability study. Potential ground-water contamination can occur from a number of sources which often include leaky underground storage tanks, agricultural activities, dairies, septic systems, r infiltration. Agricultural activities and the use of septic systems in the area should and storm orate gri 1' be considered potential ground-water contamination sources. Located to east is a small dairy. It appears to be on parcel 063-250-16, according to Parcel Quest www. arcel uest.com) this property is owned by Francisco and Laurinda Chaves. /4.3 Water Sample Location Two wells exist on the site, one agricultural and one domestic, the approximate locations of the ' wells can be seen on Plate 1. No well permits were found during file review at EHD on April 6, 2005. A water sample was taken from the well head of the domestic well by Mr. Conor McGee of our office on April 20,2005. /4.4 Water Sample Constituents The water sample was analy�6d for nitrate and DBCP. DBCP was not detected in the water sample. - Nitrate was found at 14�/L-NO3,below the maxim contaminant aminant level (MCL) of 45 mg/L- ` NO3 set by the United States EPA. The analytical reports prepared by Precision'Enviro-Tech can be i --1 found in the appendix of this report. Well construction, seals, age and depth of the well screens may play significant part in assessing the J levels of Nitrate and DBCP in various aquifers. Without knowing specific details regarding well construction and condition,it would be difficult to accurately comment of the condition of the Pi aquifer. Essentially, the water sample concentration approximately indicates the contaminant 5