Laserfiche WebLink
L <br /> LJune 12,2006 <br /> NOA Project Number: E06061A <br /> L (�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 /> the SSS. <br /> /2.3 Current and Future On-Site Ground Water Uses <br /> i <br /> One domestic water well exists on the property and is associated with the single-family residence. <br /> One irrigation well is also located on the Site. <br /> v <br /> 3.0 SOURCES AND IMPACT OF NITRATE TO GROUND WATER <br /> 6 /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 /> sources of nitrate. Septic tank use in the vicinity is discussed in Section 3.4 of the SSS. <br /> The water sample was analyzed for nitrate and DBCP. Nitrate was found at 50.8 mg/L-NO,in the <br /> domestic well, above the maximum contaminant level (MCL) set by the US EPA of 45 mg/L-NO3' <br /> DBCP was not detected in the water sample. <br /> L /3.2 Contribution of Rainfall <br /> An estimate of the quantity and quality of rainfall was required for the nitrate loading analysis. The <br /> km 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 /> 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 San Joaquin County. The average rainfall for the Lodi area <br /> 6. was found to be 17.16 inches per year for the years 1948 through 1987. <br /> L Based on this method, the average deep percolation of rain for the Lodi area is estimated to be 5.31 <br /> inches. The nitrate concentration of rainfall was estimated to be 1 mg/L-N (Hantzsche and <br /> V <br /> Finnemore, 1992). <br /> V <br /> 1 <br /> v <br /> 3 <br /> r. <br /> r,. v <br />