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r August 22, 2007 NOA Project Number: E07109A Hantzsche and Finnemore found that over a long period of time,water quality in the upper p saturated ground-water zone closely approximates the quality of percolating recharge waters. They believe that their method is a good planning tool to estimate the potential impact to groundwater, and provides useful information to planners and local officials but with some real limitations. In their article published in Ground Water, Hantzsche and Finnemore mention that "...the equation P� ignores dispersion,lateral flow, and mixing with 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, Fli 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 and 10. The units jof nitrate used in the mass balance equation are nitrate-N,whose maximum drinking water l 1 contaminant level is 10 mg/L. F1.0 CHEMICAL AND PHYSICAL PROPERTIES OF SOIL 1.1 Chemical and Physical Soil erties I Fj Five shallow percolation tests and an 8.5�the�urface tgroundwater boring were excavated by out office on, the site on July 26, 2007. The soil from of the ground to a depth of approximately 8.5 pfeet was a dark grey clay with some silt— he percolation tests were conducted for the shallow borings on the site on July 27, 2007 in accordance with the requirements of the FHD. A -' Fation of four hours was performed for each hole. Please see G1 on thepercolation test with a dur Design and Layout of the septic system for more details regarding location of the percolatjon tests. The last half an hour was observed by Mr. Nick Weisman, of the San Joaquin EHD. � For more discussion of on-site soil properties, refer to Section 7 of the SSS/NLS (Kleinfelder, E.± 2007 . a ) �i F1 F14 3 F