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February 10, 2005 <br /> NOA Project Number: E05001A <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 /> -r rainfall nitrate concentration,waste effluent quantity, and waste effluent nitrate concentration. The <br /> formula, as 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 /> i 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. <br /> 1.2 Mass Transport Soil Properties <br /> The soils were found to be fine to medium grained sand. 'A shallow percolation test set at a depth <br /> of 3 feet was found to have a rapid percolation rate 4,1J minutes per inch. No soil layering was <br /> encountered which could attenuate percolating effluent from a septic system leach field. <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. .Ground water flow direction is north at a <br /> gradient of approximately 10 feet per mile. <br /> _v <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 /> 3 <br /> �j <br />