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'? Spanos Property Page 5 <br /> Our Project Number: LGS090501 <br /> January 30, 2009 <br /> The adjusted nitrogen long term average using a weighted average is 62 mg/L-N. Below is the <br /> long term weighted average of nitrogen in the proposed development waste water. <br /> Weighted Average of Total Nitrogen <br /> Hotel: 1,095 gpd x 45 mg/L-N =49,275 <br /> Restaurant: 1,050 gpd x 60 mg/L-N = 631'000 <br /> Commercial/retail: 900 gpd x 85 mg/L-N = 76,500 <br /> =188,775 / 3,045 gpd <br /> /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 (Nz) 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 35 percent was selected for the Site because of the fine grained <br /> nature of the soils. <br /> 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 (also, see Plate 2). <br /> Table 2. <br /> S mmary of Nitrate Mass Balance E uation ... <br /> Result Average Effluent Concentration Leachfield Deep <br /> i <br /> � Parcel (Nc)* Acres(A) Daily Flow (Nw) Denitrification Percolation <br /> of Rainfall <br /> (mg/L-N)- (Q)(gpd) m9 L' (d) (R) (in) <br /> 1 12.5 17.1 2,750 62 35% 5.76 <br /> * Maximum conlqminant level(MCL for nitrate in drinking water is 10 mg/L-N. <br /> Based on the method and assumptions described, the result of the nitrate loading balance <br /> indicates that the proposed development on the proposed parcel may cause a build up of <br /> /nitrates in the aquifer above 10 mg/L-N. <br /> V/3.6 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 /> 902 Industrial Way•Lodi,CA 95240•209.367.3701 •Fax 209.369.4228 (02007 Neil 0.Anderson&Associates,Inc <br />