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June 13, 2006 <br /> NOA Project Number: E05164A <br /> and Finnemore mention that "...the equation ignores dispersion,lateral flow, and mixing with <br /> p 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 /> 1 <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 /> 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 /> The method takes into account the development area, soil denitrification factor,rainfall volume, <br /> F1rainfall 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 arc nitrate-N,whose maximum drinking water <br /> Pcontaminant level 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 S ti 5 of the SSS. <br /> 1.2 Mass Transport Soil 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 /> Fli, water table,it is possible that surface contaminates may be transported fairly rapidly. <br /> 2.0 GROUND WATER ANALYSIS <br /> F12.1 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 lies between 15 and 30 feet <br /> below ground surface and flows at a gradient of about 5 feet per mile to the east in the vicinity of <br /> the Site in 1999. <br /> 2.2 Potential Ground Water Contamination Issues <br /> F1A discussion of issues related to potential ground water contamination is included in Section 4.2 of <br /> F, 2 <br />