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Soil Suitability&Nitrate Loading Study 6Page16) <br /> St. Patrick's Church,Escalon, CA <br /> Project No. 607.1 i <br /> October 14, 2009 <br /> F! S.0 CONCLUSIONS AND RECOMMENDATIONS <br /> 8.1 Conclusions <br /> F] 1. Percolation tests were performed by NATS at the site of the tworo osed <br /> P p <br /> new septic systems. Based on the percolation test results and the soil <br /> F1J profile, we conclude that the shallow soil percolation rate may not be <br /> t- adequate for a standard—design septic sewage system. The deeper <br /> percolation tests indicated greater permeability and appear suitable for <br /> i standard septic systems. <br /> 2. The nitrate loading study indicates the existing septic system is producing <br /> i a total of about 20 pounds of nitrate nitrogen per year, and the proposed <br /> - new chapel system will add an additional approximately 55 pounds per <br /> year, and eventually, the large septic system proposed for 10 or more <br /> Fj years in the future could add an additional 636 pounds. <br /> 3. The nitrate loading study suggests the uppermost groundwater layer in <br /> the vicinity of the large, future septic system will be receiving a nitrate <br /> load that exceeds MCL limits. Given the limitations of the Hantzsche and <br /> Finnemore model, however, it is likely that actual groundwater will be <br /> 1 less affected than the model suggests, and under actual conditions may <br /> not exceed the MCL limit. <br /> Fil' <br /> 4. Based on the nitrate loading study, the uppermost groundwater layer is <br /> currently receiving a nitrate load that does not exceed MCL limits and the <br /> proposed chapel system will not increase the nitrate load sufficiently to <br /> cause the MCL limit to be exceeded. <br /> �8.2 ecommendations <br /> 1. The results of the ,this investigation suggest that a standard septic design / <br /> should be adequate for the proposed chapel provided that the deeper soil,/ <br /> F41is used for the leach system. <br /> 2. The large sysk toe constructed in 10 to 15 ye s may require some <br /> ngineered design elemen to assure proper functioni a7nd to_h4p <br /> ' in.imze the possible groundwater impact. It is assumed the system will <br /> also include a holding tank. ' <br /> 2937 Veneman Ave.,#8240 Geo-Phase Environmental Inc. Phone: (209) 569-0293 <br /> Modesto, CA 95356 Fax: (209) 569-0295 <br /> F + : <br />