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I <br /> January 16, 2007 <br /> NOA Project Number: E07009A <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 /> ` <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 /> 'F 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 1 and 2. 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 /> 4 <br /> E 1.1 Chemical and Physical Soil Properties <br /> f i <br /> I <br /> For a discussion of on-site soil properties,refer to Section 5 of the SSS. <br /> 1.2 Mass Transport Soil Properties <br /> Fine grained sediment and the degree of cementation can provide an added protection between <br /> percolating effluent at the surface and shallow ground water aquifers. The longer the effluent <br /> remains near the surface, the more treatment is enhanced due to natural processes within the soil. <br /> The soils on the site were clayey loams. Soils of this type do not typically present a high risk of <br /> 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 /> water gradient,is included in Section 4.1 of the SSS. No significant seasonal trends were evident <br /> from the maps consulted. <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 /> t <br /> a, <br /> ` l <br />