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r. 1S.s ..f <br /> ` September 10, 2004 <br /> NOA Project Number: E040104A <br /> ` Hantzsche and Finnemore found that over a long period of time, water quality in the upper <br /> saturated ground-water zone closely approximates the quality of percolating recharge waters. <br /> They believe that their method is a good planning tool and provides useful information to <br /> planners and local officials but with some real limitations. In their article published in <br /> Ground Water, Hantzsche and Finnemore mention that "...the equation ignores dispersion, <br /> lateral flow, and mixing with ground water flow from up-gradient areas. These processes <br /> would generally contribute to additional reduction of nitrate-nitrogen concentrations in <br /> ground water to the extent that the nitrate-nitrogen concentration of ground-water flow from <br /> up-gradient areas is lower." <br /> The Hantzsche and Fennemore approach is "...a conservative (worst case) first approximation <br /> of ground-water nitrate-nitrogen concentration resulting from the combined effect of on-site <br /> sewage disposal systems and precipitation. This (the equation and approach) is for estimation <br /> of long-term effect (i.e., over years) on ground-water quality, and is not intended for <br /> ` prediction of seasonal changes" (Hantzsche and Finnemore, 1992). <br /> The method takes into account the development area, soil denitrification factor, rainfall <br /> L volume, rainfall nitrate concentration, waste effluent quantity, and waste effluent nitrate <br /> concentration. The formula, assumptions and calculations used for the analysis are shown on <br /> Plates 9 through 15. The units of nitrate used in the mass balance equation are nitrate-N, <br /> whose maximum drinking water contaminant level is 10 mg/L. <br /> i.. <br /> 1.0 CHEMICAL AND PHYSICAL PROPERTIES OF SOIL <br /> 1.1 Chemical and Physical Soil Properties <br /> L <br /> For a discussion of on-site soil properties, refer to Section 5 of the SSS. <br /> 6, 1.2 Mass Transport Soil Properties <br /> Layered soils and sediments, such as the clay soils found on the Site, typically provide a degree <br /> of protection between percolating effluent at the surface and shallow ground water aquifers. <br /> Soils of this type do not typically present a high risk of excessive mass transport of nitrate or <br /> Lother constituents of concern. <br /> L <br /> L <br /> L 2 I <br /> L <br />