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�t <br /> F.> August 8, 2006 <br /> NOA Project Number: E06087A <br /> ignores dispersion,lateral flow, and mixing with ground water flow from up-gradient areas. These <br /> processes would generally contribute to additional reduction of nitrate-nitrogen concentrations in <br /> ground water to the extent that the nitrate-nitrogen concentration of ground-water flow from <br /> Fil <br /> up-gradient areas is lower." <br /> The Hantzsche and Fennemore approach is "...a conservative (worst case) first approximation of <br /> ground-water nitrate-nitrogen concentration resulting from the combined effect of on-site sewage <br /> disposal systems and precipitation. This (the equation and approach) is for estimation of long-term <br /> effect (i.e., over years) on ground-water quality, and is not intended for prediction of seasonal <br /> 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. The <br /> formula, assumptions and calculations used for the analysis are shown on Plates 9 and 10. The units <br /> of nitrate used in the mass balance equation are nitrate-N,whose maximum drinking water <br /> contaminant level is 10 mg/L. <br /> 1.0 CHEMICAL AND PHYSICAL PROPERTIES OF SOIL <br /> 1.1 Chemical and Physical Soil Properties <br /> For a discussion of on-site soil properties,refer to Section 5 of the SSS. /r9 <br /> 1.2 Mass Transport Soil Properties <br />` The percolation tests have revealed that the deeper soils are moderately permeable. The deeper soils <br /> will allow moderate infiltration of water while the surface soils are restrictive. Layered soils and <br /> sediments, such as the some fine-grained soil layers found on the Site, typically provide a degree of <br /> r7 protection between percolating effluent at the surface and shallow ground water aquifers. Soils of l` <br /> t this type do not typically present a high risk of excessive mass transport of nitrate or other <br /> a <br /> constituents of concern. <br /> I �k <br /> 2.0 GROUND WATER ANALYSIS <br /> f <br /> F2.1 Regional Ground Water <br /> n A discussion of regional ground water is included in Section 4.1 of the SSS. <br />� � F <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 /> 3 <br /> i '00,04 <br /> I <br />