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i <br /> 4 � <br /> a <br /> January 16,2007 <br /> NOA Project Number: E07009A <br /> t 3.5 Nitrate Loading Scenario <br /> A nitrate loading scenario was performed to determine the impact from the proposed project. The <br /> scenario utilizes the variables discussed previously which represent the estimated conditions and <br /> uses associated with this project. The following table presents a summary of the nitrate loading <br /> calculation for the site. <br /> Table 2. <br /> Summary of Nitrate Mass Balance Anal sis. <br /> Result Average Daily Effluent Leach6eld Deep <br /> * <br /> Acres Flow(Q) Concen- Denitrifi- <br /> Parcel (Ne) Percolation of <br /> (mNc (A) (Table 3) tration(Nw) cation(d) Rainfall(R) <br /> .� ((ggpd) (mg/L-N) (Plate 1) (in.) <br /> 3 ' 1 X32:2 ,} 216 872 85 35% 4.0 <br /> * Maximum contaminant level-(MCL)for nitrate in drinking water is 10 mg/L-N. <br /> 3.6 Impact of Nitrate Loading to Nearby Water Sources <br /> r <br /> Since the Site is relatively flat,we do not foresee percolating effluent affecting any surface water <br /> resources. <br /> 4.0 DISCUSSION OF NITRATE LOADING RESULTS <br /> M <br /> 4.1 Total Nitrate Impact <br /> Based on the method and assumptions described, the result of the nitrate loading balance indicates <br /> t :that thep�oposed development onthe proposed site could cause_a_build up of nitrates in the aquifer <br /> -'ibove 1�0 mg/L-N. Where percolating effluent leaches into the ground, ground water quality may be <br /> impacted to some degree should the effluent reach ground water. <br /> Fine-grained sediment and the degree of cementation on site can provide an added protection <br /> between percolating effluent at the surface and ground water aquifers. The longer the effluent <br /> remains near the surface, the more treatment is enhanced due to natural processes within the soil. <br /> F I _Ground water is approximately 120 feet below ground surface on the subject property. The soils on <br /> the site were clayey loatns; soils of t�liis type coo not t p can lly present a high risk of excessive mass <br /> transport of nitrate or other constituents of concern. <br /> 4.2 Methods of Mitigation <br /> An engineered treatment system is recommended to address high nitrate levels. <br /> r <br /> F <br /> F7 <br />