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February 2,2006 NOA Project Number: E05058B ground water flow from up-gradient areas. These processes would generally contribute to additional reduction of nitrate-nitrogen concentrations in ground water to the extent that the nitrate-nitrogen concentration of ground-water flow from up-gradient areas is lower." The Hantzsche and Fennemore approach is "...a conservative (worst case) first approximation of ground-water nitrate-nitrogen concentration resulting from the combined effect of on-site sewage disposal systems and precipitation. This (the equation and approach) is for estimation of long-term effect(i.e., over years) on ground-water quality, and is not intended for prediction of seasonal changes" (Hantzsche and Finnemore, 1992). The method takes into account the development area, soil denitrification factor,rainfall volume, rainfall nitrate concentration,waste effluent quantity,and waste effluent nitrate concentration. The formula,assumptions and calculations used for the analysis are shown on Plates 9 through 12. The units of nitrate used in the mass balance equation are nitrate-N,whose maximum drinking water contaminant level is 10 mg/L. 1.0 CHEMICAL AND PHYSICAL PROPERTIES OF SOIL 1.1 Chemical and Physical Soil Properties For a discussion of on-site soil properties,refer to Section 5 of the SSS. 1.2 Mass Transport Soil Properties The percolation tests have revealed that the soils are fairly permeable. These soils will allow moderate to rapid infiltration of water through the surface soils. If the sandy soils exist to the depth of the ground water table,it is possible that surface contaminates may be transported fairly rapidly. 2.0 GROUND WATER ANALYSIS 2.1 Regional Ground Water A discussion of regional ground water is included in Section 4.1 of the SSS. / 2.2 Potential Ground Water Contamination Issues A discussion of issues related to potential ground water contamination is included in Section 4.2 of the SSS. 2 .,004