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August 5, 2005 <br /> NOA Project Number: E05098A <br /> the SSS. <br /> /2.3 Current and Future On-Site Ground Water Uses <br /> r i planned to be for the proposed development. The uses will include domestic and <br /> Ground Ovate s p p p p <br /> water for winery processes. An existing agricultural well provides water.for pasture irrigation and <br /> cattle watering. <br /> 3.0 SOURCES AND IMPACT OF NITRATE TO GROUND WATER <br /> . J <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 /> es of nitrate. Septic tank use in the vicinity is discussed in Section 3.4 of the SSS. <br /> sources p ty <br /> The onsite water well was tested for nitrate and DBCP. Nitrate was found at 13.8 mg/L-NO3, <br /> which is below 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 /> p <br /> Though the water sample indicated some nitrates, this is not unusual. The concentration of nitrate <br /> g <br /> in the well water sample analyzed (in this one test only) does not suggest to our office any unusual <br /> + or non-typical nearby nitrate sources however, this is only one sample representing the conditions at <br /> that day and time in the aquifer. <br /> L <br /> /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. An estimate of potential deep percolation of <br /> rain determines whether the average monthly precipitation exceeds average monthly potential <br /> evapotranspiration. If so, then the difference is potential deep percolation. This method does not <br /> consider runoff. See Plate 9 for the data and calculation. <br /> Average potential evapotranspiration was obtained from the California Irrigation Management <br /> Information System (CIMIS). Stockton is located within evapotranspiration zone number 12. The <br /> average rain fall for the Stockton area was obtained from the Western Regional Climate Center <br /> i (www.wrcc.dri.edu), and was found to be 17.57 inches per year for the years 1948 through 2004. <br /> Based on this method, the average deep percolation of rain for the Lodi-area is estimated to be 5.76 <br /> inches. The nitrate concentration of rain fall was estimated to be 1 mg/L-N (Hantzsche and . <br /> Finnemore, 1992). <br /> 3 <br />