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L 16w� <br /> `, December 1,2004 <br /> NOA Project Number: E040117A <br /> Water, Hantzsche and Finnemore mention that "...the equation ignores dispersion, lateral flow, <br /> and mixing with ground water flow from up-gradient areas. These processes would generally <br /> contribute to additional reduction of nitrate-nitrogen concentrations in ground water to the extent <br /> ` that the nitrate-nitrogen concentration of ground-water flow from up-gradient areas is lower." <br /> The Hantzsche and Fennemore approach is "...a conservative (worst case) first approximation of <br /> rw 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 <br /> long-term effect(i.e.,over years) on ground-water quality, and is not intended for prediction of <br /> 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 9 through <br /> 12. The units of nitrate used in the mass balance equation are nitrate-N, whose maximum <br /> drinking water contaminant level is 10 mg/L. <br /> 1.0 CHEMICAL AND PHYSICAL PROPERTIES OF SOIL <br /> /.1 Chemical and Physical Soil Properties <br /> L <br /> For a discussion of on-site soil properties, refer to Section 5 of the SSS. <br /> L /1.2 Mass Transport Soil Properties <br /> Layered soils and consistency of fine grained sediments or cement, such as the clayey soils found <br /> ` on the Site,typically provide an added degree of protection between percolating effluent at the <br /> surface and shallow ground water aquifers. Soils of this type do not typically present a high risk <br /> i of excessive mass transport of nitrate or other constituents of concern. <br /> 2.0 GROUND WATER ANALYSIS <br /> 2.1 Regional Ground Water <br /> A discussion of regional ground water, including depth to ground water and directional ground <br /> 6' water gradient, is included in Section 4.1 of the SSS. No significant seasonal trends were evident <br /> from the maps consulted. <br /> 2 <br /> 6. .,44 <br />