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F1 <br /> F1 July 11, 2007 <br /> NOA Project Number: E07094A <br /> Fj2.3 Current and Future On-Site Ground Water Uses <br /> The use of ground water for drinking water is planned for the proposed development.There are <br /> Ficurrently two wells on the site. <br /> Fj 3.0 SOURCES AND IMPACT OF NITRATE TO GROUND WATER <br /> 3.1 Current Off-Site Sources of Nitrate <br /> FSeptic systems, agriculture, and dairies in the area may be the most significant sources of nitrate. <br /> Septic tank use in the vicinity discussed in Section 3.4 was found to be moderate. The onsite water <br /> "+ well was tested for nitrate and DBCP. Nitrate was found at 1.0 mg/L-N031 which is well below the <br /> maximum contaminant level (MCL) set by the US EPA of 45 mg/L-NO3. DBCP was not detected <br /> in the water sample. <br /> A <br /> 3.2 Contribution of Rainfall <br /> 0 An estimate of the quantity and quality of rainfall was required for the nitrate loading analysis. The <br /> estimate of deep percolation of ram is based on the average monthly precipitation of rain fall and <br /> evapotranspiration for Stockton, California. The estimate first determines whether the average <br /> monthly precipitation exceeds average monthly potential evapotranspiration. If so, then the <br /> F;i difference is potential deep percolation. This method does not consider runoff. See Plate 1 for the <br /> data and calculation. <br /> PAverage 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 /> (www.wrcc.dri.edu), and was found to be 14.96 inches per month for the years 1965 through 1977. <br /> �} Based on this method, the average deep percolation of rain for the Stockton area is estimated to be <br /> 4.00 inches. The nitrate concentration of rain fall was estimated to be 1 mg/L-N (Hantzsche and <br /> Finnemore, 1992). <br /> FJ1 3.3 Current On-Site Sources of Nitrate <br /> Current on-site sources of nitrate include the current septic systems on the property. No additional <br /> sources of nitrates besides septic effluent,groundwater and rainfall are recognized. <br /> 4 <br /> 4 <br />