Laserfiche WebLink
February 22, 2006 <br /> NOA Project N <br /> / 1 umber: E060MA <br /> �/ 2.2 Potential Ground Water Contamination Issues <br /> A discussion of issues related to potential ground water contamination is included in Section 4.2 of <br /> E <br /> the SSS. <br /> 2.3 Current and Future On-Site Ground Water Uses <br /> ' One domestic water well exists on the property and is associated with the single-family residence. <br /> F� One irrigation well is also located on the Site. <br /> 3.0 SOURCES AND IMPACT OF NITRATE TO GROUND WATER <br /> /3.1 Current Off-Site Sources of Nitrate <br /> We recognize that septic systems, agriculture, and dairies in the area may be the most significant <br /> Fj sources of nitrate. Septic tank use in the vicinity is discussed in Section 3.4 of the SSS. <br /> The water sample alyze• for nitrate and DBCP. Nitrate was foun t 2.5Lnng/L:-N in the <br /> domestic well and 3. mg/Uin the irri anon well we 3 <br /> 3 g well below the maxim <br /> ant level <br /> (MCL) set by the US EPA of 45 mg/L-NO3. DBCP was not detected in either water sample. <br /> / <br /> F Y 3.2 Contribution of Rainfall <br /> An estimate of the quantity and quality of rainfall was required for the nitrate loading analysis. The <br /> estimate of deep percolation of rain is based on the average monthly precipitation of rain fall and <br /> evapotranspiration for the Lodi area of California (the closest data set available). An estimate of <br /> F <br /> potential deep percolation of rain determines whether the average monthly precipitation exceeds <br /> average monthly potential evapotranspiration. If so, then the difference is potential deep <br /> percolation. This method does not consider runoff See Plate 9 for the data and calculation. <br /> Average potential evapotranspiration data were obtained from the California Irrigation Management <br /> Information System (CIMIS). Lodi is located within evapotranspiration zone number 12. Rainfall <br /> data was obtained from the Soil Survey of Stan Joaquin County. The average rainfall for the Lodi area <br /> 1 was found to be 17.16 inches per year for the years 1948 through 1987. <br /> Based on this method, the average deep percolation of rain for the Lodi area is estimated toC5.31) <br /> inches. The nitrate concentration of rainfall was estimated to be 1 mg/L-N (Hantzsche and <br /> FJFinnemore, 1992). <br /> lea <br /> 7 3 <br /> IE <br /> '044 <br />