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i <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 /> i 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 5 through 6. 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 /> r. <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 percolation tests have revealed that the soils are low to moderately permeable. These soils will <br /> allow slow infiltration of water through the surface soils. Layered soils and sediments, such as the % <br /> r. some fine-grained soil layers found on the Site,typically provide a degree of protection between <br /> percolating effluent at the surface and shallow ground water aquifers. Soils of this type do not <br /> typically present a high risk of excessive mass transport of nitrate or other constituents of concern. <br /> i <br /> 2.0 GROUND WATER ANALYSIS <br /> r <br /> 2.1 Regional Ground Water <br /> A discussion of regional groundwater is included in Section 4.1 of the SSS. i <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 /> i <br />