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+ Page 2 <br /> Spanos Property <br /> Our Project Number: LGS090501 <br /> January 30, 2009 <br /> /hese processes would generally contribute to additional reduction of nitrate-nitrogen <br /> concentrations in ground water to the extent that the nitrate-nitrogen concentration of ground- <br /> water flow from up-gradient areas is lower." <br /> f <br /> -The Hantxsche and Fennemore approach is "...a conservative (worst case) first approximation <br /> of ground-water nitrate-nitrogen concentration resulting-from the-combined effect of on-site <br /> sewage disposal systems and precipitation. This (the equation and approach) is for estimation <br /> of long-term effect (i.e., over years) on ground-water quality, and is not intended for prediction <br /> t of seasonal changes" (Hantzsche and Finnemore, 1992). <br /> The method takes into account the development area, soil denitrification factor, rainfall volume, <br /> rainfall nitrate concentration, waste effluent quantity, and waste effluent nitrate concentration. <br /> The formula, assumptions and calculations used for the analysis are shown on Plates 1 and 2. <br /> The units of nitrate used in the mass balance equation are nitrate-N, whose maximum drinking <br /> water contaminant level is 10 mg/L. <br /> /1.0 CHEMICAL AND PHYSICAL PROPERTIES OF SOIL <br /> /1.1 Chemical and Physical Soil Properties <br /> s <br /> For a discussion of on-site soil properties, refer to Section 5 of the SSS completed by Dillon & <br /> Murphy. <br /> 1.2 Mass Transport Soil Properties <br /> The percolation tests have-revealed that the soils are--permeable to the maximum depth of <br /> exploration of 42-inches. These soils will allow moderately.slow infiltration of water through the <br /> surface soils. Finer grain soils tend to slow the downward movement of percolating effluent <br /> from a septic system disposal field when compared to sandy soils. Due to the lack of sandy <br /> soils below the site, the potential impact to deep ground water is reduced when compared to <br /> 'other sites with thicker sections of sandy soil. The longer the effluent remains near the surface, <br /> the more treatment occurs due to natural processes within the soil. <br /> 2.0 GROUND WATER ANALYSIS <br /> 2.1 Regional Ground Water <br /> Regional ground water information, including depth to ground water and directional ground <br /> water gradient, is discussed in Section 4.1 of the SSS completed by Dillon & Murphy. <br /> 2.2 Potential Ground Water Contamination Issues <br /> 6 <br /> A discussion of issues related to potential ground water contamination is included in Section 4.2 <br /> of the SSS completed by Dillon.& Murphy. <br /> 902 Industrial Way•Lodi,CA 95240•209.367.3701 •Fax 209.369.4228 ©1007 Nei!0.Anderson&Associates,Inc <br />