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Bail Bond Business Page 8 of 13 Our Project Number: LGS080549 January 13, 2009 The method utilized for the nitrate loading analysis is based on a simple mass balance formula, discussed in a published article by Hantzsche and Finnemore (1992), which provides a convenient and simplified method to estimate long-term ground-water nitrate impacts on an area-wide basis. Hantzsche and Finnemore found that over a long period of time, water quality in the upper saturated ground-water zone closely approximates the quality of percolating recharge waters. They believe that their method is a good planning tool 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 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, rainfall nitrate concentration, waste effluent quantity, and waste effluent nitrate concentration. The formula, assumptions and calculations used for the analysis are shown on Plates 7 and 8. The units of nitrate used in the mass balance equation are nitrate-N, whose maximum drinking water contaminant level is 10 mg/L. 2.1 Chemical and Physical Properties of Soil 2.1.1 Chemical and Physical Soil Properties For a discussion of on-site soil properties, refer to Section I.5. 2.1.2 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. The longer the effluent remains near the surface, the more treatment is enhanced due to natural processes within the soil. If the permeable soils exist to the depth of the ground water table, it is possible that surface contaminants may be transported fairly rapidly. .*44 902 Industrial Way• Lodi,CA 95240•209.367.3701 • Fax 209.369.4228 02008 Neil O.Anderson&Associates,Inc