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kn KLEINEELDER <br /> N, = 1.0(2)(40)(1 -0.3) + 0.5(11.9) - 56.0+ 6.0 = C4.5mg/1 as N <br /> Ll1.0(2) + 11.9 2.0 + 1-1.9 <br /> Commercial Parcel <br /> At the time of this writing, the type of development that will occur on the proposed commercial <br /> parcel is not known. In order to estimate the nitrate loading on the commercial parcel we have <br /> assumed that the site will be developed as a retail establishment with restroom facilities for <br /> employee:and public use.- For the purposes of this evaluation, we have assumed a total Qf 7 <br /> t_oilet_f"ixtures will be on the site, and each fixture will use 150 gallons of water per day. We <br /> have also assumed that paved parking areas will be placed over portions of the site that will <br /> reduce the amount of deep percolation of precipitation that occurs. If the actual uses are <br /> different than assumed above, our office should be contacted that we may evise these <br /> estimates as needed. ' <br /> NC = Average calculated nitrate-nitrogen in groundwater resulting from domestic sources <br /> and precipitation-mg/l, as N. <br /> A = Number of dwelling units per acre on septic tanks (unit/acre) =Qased on 7 <br /> toilet fixtures using 150 gal/day each; divided by 150 gal/day/dwelling unit, divided i <br /> by 6.5 acres.) <br /> W = Annual wastewater loading per dwelling unit per acre (inches) =2.0 inches (per year <br /> per dwelling unit assuming a flow of 150 gal/day/dwelling unit.) <br /> NW = Nitrate concentrationro -nitnfed�leaph�field effluent (mg/1) = 7,0-Mg/1 ((Hantzsche <br /> and Finnemore (1992This value selected for commercial uses based on past <br /> discussions with Mr. Mike Huggins of SJCEHD.) <br /> D = Percent dentrification of leachfield effluent= 0.3 percent (0.1 to 0.35 percent typical <br /> per Hantzsche and Finnemore (1992)). 0.3 selected given the depth to groundwater. <br /> R = Annual deep. percolation of precipitation (inches) cher (representing 55 <br /> percent of the average annual rainfall of approximately 17 inches. The remaining 45 <br /> _ percent of rainfall is assumed to drain off-site into natural or manmade drainages or <br /> be lost to evapotranspiration.) # <br /> Nb Background nitrate nitrogen concentration of rainfall recharge at the water table = <br /> i-5 mg/l (per Technical Memorandum, Hydrologic and Soil Investigation for the <br /> Chico Urban Area,page 6, Dames and Moore, April 1996) <br /> i Our calculation is as follows; <br /> L <br /> 55208.GO1/ST05R644 June 1,2005 <br /> ©2005 Kleinfelder,Inc. . Page 7 of 9 <br />