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December 23, 2005 <br /> NOA Project Number: E05174A <br /> saturated ground-water zone closely approximates the quality of percolating recharge waters.They <br /> ,/believe that their method is a good planning tool and provides useful information to planners and <br /> local officials but with some real limitations. In their article published in Ground Water, Hantzsche <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 /> F 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 /> 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 /> t 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 9 and 10. The units <br /> of nitrate used in the mass balance equation are nitrate-N whose maximum drinking <br /> water <br /> contaminant level is 10 mg/L. <br /> 1.0 CHEMICAL AND PHYSICAL PROPERTIES OF SOIL <br /> �1.1 Chemical and Physical Soil Properties <br /> perties, refer to Section 5 of the SSS. <br /> For a discussion of on-site soil pro <br /> 1.2 Mass Transport Soil Properties <br /> k The soils on the site were found to be fine-grained and with low infiltration rates. These soils will <br /> tend to attenuate and restrict the downward percolation of septic system effluent through the <br /> surface soils. <br /> G <br /> 2.0 GROUND WATER ANALYSIS <br /> { . i 2.1 Regional Ground Water <br /> Ground water lies deep below the Site most likely below 200 feet. The site is just east of contours <br /> shown on the county ground water map. Just west of the site,ground water is approximately 230 <br /> { feet below the ground surface. <br /> i <br /> 3 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 /> 2 <br />