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!, May 17,2007 <br /> NOA Project Number: E07064A <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 /> up-gradient areas is lower." <br /> The Hantzsche and Fennemore approach is "...a conservative (worst case) first approximation of <br /> F1 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 /> Fji 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 /> F! <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. <br /> 1.2 Mass Transport Soil Properties <br /> Layered soils and sediments, such as the fine-grained soil layers found on the site, typically provide a <br /> degree of protection between percolating effluent at the surface and shallow ground water aquifers. <br /> E j Soils of this type do not typically present a high risk of excessive mass transport of nitrate or other <br /> constituents of concern. <br /> 2.0 GROUND WATER ANALYSIS <br /> 2.1 Regional Ground Water <br /> A discussion of regional ground water is included in Section 4.1 of the SSS. <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 Z Z, <br /> the SSS. <br /> � J <br /> 3 <br /> P <br /> 1 <br />