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KLE/NFELOER <br /> &igMPoppM PI9Ff5olulbn. <br /> Fraction of nitrate-nitrogen loss due to dentrification of leach field effluent'= 0.30 <br /> ' — percent (Per Hantzsche and Finnemore (1992), 0.10 to 0.35 is typical). The 0.30 <br /> D value was selected given that groundwater in the project area is relatively deep and <br /> the subsurface soils are interbedded with fine-grained soils that would inhibit or slow <br /> infiltration of effluent to the groundwater <br /> ' Average recharge rate of rainfall = 11.25 inches per year (representing 80 percent of <br /> R _ the average annual rainfall of approximately 14.06 inches. The remaining 20 percent <br /> ' of rainfall is assumed to drain off-site into natural or manmade drainages or be lost <br /> to evapotranspiration.) <br /> ' Background nitrate nitrogen concentration of rainfall recharge at the water table= 0.5 <br /> Nb = mg/I (per Technical Memorandum, Hydrologic and Soil Investigation for the Chico <br /> Urban Area, page 6, Dames and Moore, April 1996) <br /> ' Our calculation is as follows: <br /> ' 1.07(45)(1-0.30) + 11.25(0.50) = 3.19 mg/I as N <br /> INC _ <br /> (1.07 + 11.25) <br /> ' Given the above factors, we estimate that the existing and proposed facilities within the parcel <br /> would require an average waste/sewage flow of 68,390 gallons per week in order to exceed the <br /> state drinking water standard for nitrogen (N) of 10 mg/I in groundwater. <br /> ' <br /> 20162869.001 A/STO1 6R38644 Page 11 of 15 April 19, 2016 <br /> ©2016 Kleinfelder <br />