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GEOTECHNICAL <br /> NEIL O. ANDERSON ENVIRONMENTAL <br /> AN D ASSOCIATES <br /> INSPECTIONS a TESTING <br /> LABORATORY SERVICES <br /> POOL ENGINEERING <br /> ` POST TENSION DESIGN <br /> April 7, 2006 <br /> NOA Project Number: E06020A <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 /> the SSS. <br /> 2.3 Current and Future On-Site Ground Water Uses <br /> The use of ground water is planned for the proposed development. There is currently one well on <br /> the Site. According to the property owner, Samad Aziz, this well will be used for the proposed <br /> general store on the site.The well also serves the trailer and the mobile home on the property. <br /> 3.0 SOURCES AND IMPACT OF NITRATE TO GROUND WATER <br /> 3.1 Current Off-Site Sources of Nitrate <br /> Septic 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 low. The onsite water well <br /> _ was tested for nitrate and DBCP. Nitrate was fouga at 4,$mg/L-NO3,which is below the <br /> maximum contaminant level (MCL) set by the US EPA o f 45 mg/L-NO3. DBCP was not detected <br /> in the water sample. <br /> ` 3.2 Contribution of Rainfall <br /> imp 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 Tracy, California.The estimate first determines whether the average monthly <br /> precipitation exceeds average monthly potential evapotranspiration. If so, then_the difference is <br /> potential deep percolation. This method does not consider runoff. See Plate 9 i'or the data and <br /> calculation. <br /> Average potential evapotranspiration was obtained from the California Irrigation Management <br /> Information System (CIMIS). Tracy is located within evapotranspiration zone number 12. The <br /> average rain fall for the East Tracy area was obtained from the Western Regional Climate Center <br /> (www.wrcc.dri.edu),and was found to be 9.94 inches per month for the years 1965 through 1977. <br /> Y Based on this method, the average deep percolation of rain for the East Tracy area is estimated to be <br /> 4 <br /> LODI ■ SACRAMENTO ■ MODESTO <br /> L <br /> ENVIRONMENTAL DIVISION 902 Industrial Way,Lodi,California 95240 ■209.367.3701 0 209.369.4228 0 www.noar <br />