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«Project Name» Page 7 <br /> Our Project Number: LGS080005 <br /> February 28, 2008 <br /> Table S. <br /> Sum ary of Percolation Tests. <br /> Test No., Percolation Test Percolation Rate Comments <br /> Date Tested Depth (%) (minutes/inch) Test Duration (see notes) <br /> P-1 (shallow) 3.15 No movement 4-hr Failing rate <br /> 2-7-08 <br /> P-1 (deep) 5.5 13.8 4-hr Satisfactory perc rate <br /> 2-7-08 <br /> Note: A satisfactory percolation rate for a"shallow"test is less than or equal to 60 minutes per inch. <br /> A satisfactory percolation rate for a"deep"test is less than or equal to 30 minutes per inch. <br /> 1.6.7 Discussion of Percolation Test Results <br /> • The soils within the sewage disposal areas of the site have demonstrated a satisfactory <br /> percolation rate in accordance with the requirements of the EHD for the use of a standard <br /> septic system. <br /> 1.6.8 Discussion of Seotic System Sizing <br /> Septic system construction should follow the San Joaquin County On-Site Wastewater Disposal <br /> Standards where applicable. <br /> 2.0 NITRATE LOADING STUDY <br /> Because of concern regarding nitrate leaching into ground water from septic systems, a nitrate <br /> loading analysis was required by the EHD for the proposed development to measure the <br /> potential concentration of percolating effluent and rain fall over the long term. Where <br /> percolating effluent leaches into the ground, ground water quality may be impacted to some <br /> degree should the effluent reach ground water. <br /> The method utilized for the nitrate loading analysis is based on a simple mass balance formula, <br /> discussed in a published article by Hantzsche and Finnemore (1992), which provides a <br />_ convenient and simplified method to estimate long-term ground-water nitrate impacts on an <br /> area-wide basis. <br /> Hantzsche and Finnemore found that over a long period of time, water quality in the upper <br /> saturated ground-water zone closely approximates the quality of percolating recharge waters. <br /> They believe that their method is a good planning tool and provides useful information to <br /> planners and local officials but with some real limitations. In their article published in Ground <br /> Water, Hantzsche and Finnemore mention that "...the equation ignores dispersion, lateral flow, <br /> and mixing with ground water flow from up-gradient areas. These processes would generally <br /> contribute to additional reduction of nitrate-nitrogen concentrations in ground water to the <br /> extent that the nitrate-nitrogen concentration of ground-water flow from up-gradient areas is <br /> lower." <br /> .,04 <br /> 902 Industrial Way•Lodi,CA 95240• 209.367.3701 •Fax 209.369.4228 02008 Neil O.Anderson&Associates,Inc <br />