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Watts Winery *ft.�%� � -.OF Page 12 of 14 <br /> Our Project Number: LGS090507 <br /> May 11, 2009 <br /> water for the commercial aspect of the project is approximately 85 mg/L-N over the long term. <br /> The adjusted nitrogen long term average using a weighted average is 53.55 mg/L-N. Below is <br /> the long term weighted average of nitrogen in the proposed development waste water. <br /> 280 gpd x 45 mg/L-N = 12,600 <br /> 90 gpd x 65 mg/L-N 5,850` <br /> 18,450 / 370 gpd4t%8 mg/L-N <br /> 2.3.4.2 Denitrification Estimate <br /> Denitrification is an important process which occurs within the leach field whereby certain <br /> bacteria utilize the oxygen in the nitrate (NO3) and release nitrogen gas (N2) to the atmosphere. <br /> Denitrification is expressed as a percentage, and the normally accepted range is 10 percent to <br /> 35 percent. Soils with higher clay content, moist soil conditions, high pH, and organic material <br /> denitrify by about 35 percent, and soils with high sand content and fast percolation rates are <br /> estimated to denitrify at a lower rate, about 10 percent to 15 percent. <br /> A denitrification factor of 25 percent was selected for the Site because of the fine grained <br /> nature of the soils at the site, and relatively slow percolation rate. <br /> 2.3.5 Nitrate Loading Scenario <br /> A nitrate loading scenario was performed to determine the impact from the proposed project. <br /> The scenario utilizes the variables discussed previously which represent the estimated <br /> conditions and uses associated with this project. The following table presents a summary of the <br /> _ nitrate loading calculation for the site, as presented in Plate 10. <br /> Table S. <br /> Summary of Nitrate Mass Balance E uation. <br /> Result Average Effluent Leachfleld Deep <br /> Parcel (Nc)*-- Acres(A) Daily Flow Concentration Denitrification Percolation <br /> mg/L-N) (Q) (gpd) (Nw) (d) of Rainfall <br /> (mg/L-N) (R)(in) <br /> 1 8.3 14.43 154 66.8 25% 5.67 <br /> * Maximum contami vel(MCL)for nitrate in drinking water is 10 mg/L-N. <br /> 2.3.6 Impact of Nitrate Loading to Nearby Water Sources <br /> Since the Site is relatively flat, we do not foresee percolating effluent affecting any surface <br /> water resources. <br /> L <br /> ` <br /> 902 Industrial Way•Lodi,CA 95240•209.367.3701 •Fax 209.369.4228 02009 Neil O.Anderson&Associates.Inc <br />