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L <br /> July 5, 2005 <br /> NOA Project Number: E05027A <br /> Table 2. <br /> Summary of Nitrate Mass Balance Analysis. <br /> Result Average Daily Effluent L.eachfield Deep <br /> Plate (Nc) t Acres Flow(Q) Concen- Denitrifi- Percolation of <br /> (mNc * (A) (Table 3) tration(Nw) cation(d) Rainfall(R) <br /> (gpd) (mg/L-N) (Plate 9) (in.) <br /> 10 12.7 1.16 350 45 35% 5.76 <br /> Maximum contaminant level(MCL) for nitrate in drinking water is 10 mg/LrN. <br /> 4.6 Impact of Nitrate Loading to Nearby Water Sources <br /> L <br /> Based on the method and assumptions described the proposed project may cause a build up of <br /> nitrate in the ground water above 10 mg/L-N (12.7 mg/L-N) for the site over the long term. <br /> However, due to the fine grained soils,geological units, and percolation test information (no <br /> movement at end of percolation test) in addition to the deep depth of ground water (110 to 120 <br /> feet),it is doubtful whether the aquifer will be affected at all by this development. It is likely that the <br /> concentration of nitrates percolating below the site will be attenuated by the fine-grained soils. <br /> Since the Site is relatively flat,we do not foresee percolating effluent affecting any surface water <br /> resources. <br /> 5.0 DISCUSSION OF NITRATE LOADING RESULTS <br /> 6. <br /> 5.1 Total Nitrate Impact <br /> 61 Based on the method and assumptions described, the result of the nitrate loading balance indicates <br /> that the proposed development on the parcel may cause a build up of nitrate in the ground water <br /> above 10 mg/L-N (12.7 mg/L-N) over the long term. <br /> L <br /> However, due to the fine grained soils,geological units,and percolation test information (no <br /> movement at end of percolation test) in addition to the deep depth of ground water (110 to 120 <br /> L feet),it is doubtful whether the aquifer will be affected at all by this development. It is likely that the <br /> concentration of nitrates percolating below the site will be attenuated by the fine-grained soils. <br /> 5.2 Methods of Mitigation <br /> No mitigation is proposed. Our office believes that the presence of cemented and fine grained soils <br /> ►. on the site will provide a significant battier between the percolating effluent and the ground water. <br /> The deep level of the ground water below the site and the cemented clayey soils sufficient to prevent <br /> the long term build up of nitrate in the aquifer. <br /> L <br /> V <br /> 6 <br /> L <br />