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LNovember 8, 2004 <br /> NOA Project Number: E040110A <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 /> r <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 /> LThe method takes into account the development area,soil denitrification factor,rainfall volume, <br /> L 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 through 15. The <br /> units of nitrate used in the mass balance equation are nitrate-N,whose maximum drinking water <br /> contaminant level is 10 mg/L. <br /> L V/LO CHEMICAL AND PHYSICAL PROPERTIES OF SOIL <br /> LJ/1.1 Chemical and Physical Soil Properties <br /> LFor a discussion of on-site soil properties,refer to Section 5 of the SSS. <br /> d 12 Mass Transport Soil Properties <br /> LLayered soils and sediments, such as the silty soils found on the Site, typically provide a degree of <br /> protection between percolating effluent at the surface and shallow ground water aquifers. Soils of <br /> L this type do not typically present a high risk of excessive mass transport of nitrate or other <br /> constituents of concern. <br /> k12.0 GROUNDWATER ANALYSIS <br /> Lv 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 appears to be ten feet deeper <br /> and to have a greater gradient down to the north in the fall than the spring. <br /> L ` 2.2 Potential Ground Water Contamination Issues <br /> LA discussion of issues related to potential ground water contamination is included in Section 4.2 of <br /> the SSS. <br /> L <br /> L 3 <br /> L <br />