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Marcb 26,2003 Job Number:LG02-031 Page 9 percolation rates are estimated to denitrify at a lower rate, about 10 percent tol5 percent. Due to the mixture of silty and clayey soils existing to a depth of 40 feet, the denitrification factor is ., estimated to be 25 percent. An estimate of the quantity and quality of rainfall was required for the analysis. The deep percolation of rain was estimated to be 3.38 inches and the calculation is shown on Plate 8. The nitrate concentration of rain fall was estimated to be 1.0 mg/L-N.' 5.2 Summary of Nitrate Balance Table 5 presents the summary of the nitrate loading analysis utilizing the Hantzsche and Finnemore method described previously. As a result of the analysis, the use of a conventional septic system will not cause a build up of nitrates above the maximum contaminate level for nitrate of 10 mg/L-N given the assumptions discussed previously. Please note, this estimate was for the Phase I portion of the project only. Additional phases may cause an increase above 10 mg/L-N. The following table provides a summary of the nitrate loading calculation. Table 5. Summary of Nitrate Mass Balance Analysis. = z G W E n E B a 6�. v w m ria v x Z ag CO s U .� 9.6 40 5,209 35 25 3.38 1.0 *Note:Maximum contaminate level(MCL)for Nitrate is 10 mg/L-N. 6.0 CONCLUSIONS AND RECOMMENDATIONS In conclusion, a satisfactory percolation rate was achieved on the parcel. The depth to ground water on the site was found to be 29.5 feet on February 11, 2003. The ground-water quality test indicates that DBCP was non-detectable (ND) and nitrate as Nitrogen(l)was 14 mg/L. The ` result of the nitrate test indicates the ground water is above the maximum contaminate level set by the United States Environmental Protection Agency of 10 mg/L-N OE9S01 O A I,E p��r