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2nd Addendum-Soil Suitability&Nitrate Loading Study Page 3 Oak Farm Winery,Lodi CA Project No. 670.1C November 20,2013 surface 2.99 mg/L of nitrogen, or 30 percent of the established maximum contaminant limit of 10 mg/L. The future system is estimated to result in nitrate loading to groundwater that will not exceed the MCL limit. This calculation does not consider the dilution that occurs as newly introduced water mixes with the deeper groundwater. The calculated groundwater concentrations offer a "worst case" estimate. The existing nitrate level from the laboratory analysis of well water is 26 mg/L which converts to 5.9 mg/L of nitrogen. The total nitrogen as nitrogen load from all three septic systems plus the existing groundwater nitrate would therefore be 8.9 mg/L (3.0+5.9) which is less than the MCL concentration of 10 mg/L. 8.0 CONCLUSIONS AND RECOMMENDATIONS 8.1 Conclusions 1. A percolation test were performed at the site of the new septic system. Based on the percolation test results and the soil profile, we conclude that the shallow soil percolation rate is suitable for a "standard design" septic system. 2. The nitrate loading study indicates the proposed new septic system will add an additional approximately 65 pounds per year and that the new and existing systems combined will produce about 117 pounds per year. 3. The nitrate loading study suggests the uppermost groundwater layer in the vicinity of the septic systems will be receiving a nitrate load that does not exceed MCL limits. 4. The groundwater water well sample contains no detectable DBCP. 8.2 Recommendations The results of the this investigation suggest that a standard septic design should be used for the proposed new septic system. 2937 Veneman Ave.,#B240 Geo-Phase Environmental Inc. Phone: (209)569-0293 Modesto,CA 95356 Fax: (209)569-0295