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February 15, 2006 <br /> NOA Project Number: E06006A . <br /> and Finnemore mention that .-..the equation ignores dispersion, lateral flow, and mixing with <br /> ground water flow from up-gradient areas.. These processes would generally contribute to additional <br /> reduction of nitrate-nitrogen concentrations in ground water to the extent that the nitrate-nitrogen <br /> 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 /> F11 ground-water nitrate-nitrogen concentration resulting from the combined effect of on-site sewage <br /> 1 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 10 and 11. The <br /> units of nitrate used in the mass balance equation are nitrate-N, the maximum drinking water <br /> Fcontaminant level of which 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 Sail Properties <br /> The soils on the site were found to be fairly sandy. These soils will allow moderate to rapid <br /> infiltration of water through the surface soils. If the sandy soils exist to the depth of the ground <br /> water table,it possible that surface contaminants may be transported fairly rapidly to the aquifer. <br /> 2.0 GROUNDWATER ANALYSIS <br /> 2.1P 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 lies between 18 and 28 feet <br /> below.ground surface and flows at a gradient of about 5 feet per mile to the north-northeast in the <br /> vicinity of the Site. <br /> tJ <br /> 2 <br />