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Values and Assumptions <br /> J= 2,891,000 gals=total_WW/)j= 387,000 cu ft/yr= 0.97 in/yr <br /> 110 Ac x 43,560 sq ft/Ac x (1 ft/12 in) <br /> Nw— 53 ing <br /> d ssume 15% due to.a fine-grained clay sail-at soil/effluent interface: <br /> R = 9 in/yr.Y <br /> Nb= Assumed to be 0.1 ppm NO3-N <br /> 0.97 in/yr(53 mg N/L) (1 - 0.15)+ [9 in/yr-x 0.1 mg/Q <br /> Nr = (097 in/yr+ 9 in/yr) <br /> t <br /> Nr =, 4.5:ppm as.nitrate-nitrogen(NO3-NYor 21 ppm-as nitrate-(NO) <br /> NLS" Nr is api2roximately one-half the Maximum Contaminant Level MCL or nitrate- <br /> nitrogen 10 m . .This concentration can be considered downgradient im act. <br /> k <br /> VI. CONCLUSIONS AND RECOMMENDATIONS <br /> SSS§ 6.8 The perc test results for the 11 parcels show acceptable percolation for the management <br /> of the anticipated septic sstem effluent flows. The shallow percolation test results are <br /> representative of effluent percolation that will occur from leachlines. Only Parcels 10 and 16 <br /> demonstrated mediocre perc rates. All the remainmgelsrevealed excel <br /> _Parce „excellent nt percolation. <br /> _� „ .e._... <br /> Sin ec he water table was determined to be at 7.5 feet u gradient- the <br /> average water le t hallow <br /> water table depth precludes the use of sumps or seepage pits in this area of San Joaquin County. <br /> Septic effluent emanating from the proposed residential structures must be managed entirel by <br /> leachlines. <br /> ue to seasonal water table fluctuations, particularly increases in elevation from surrounding <br /> irrigated agricultural fields, septic systems should not be placed within 100 feet of any heavily <br /> irrigated field, or irrigation pond. <br /> EHD requires that there be sufficient distance for"treatment" of septic effluent before it encounters <br /> the groundwater table. This distance is normally regarded to be five feet in leachlines and 10 feet <br /> with seepage pits. Therefore, marginally sufficient distance exists between the bottom of a <br /> leachline trench at 42 inches and the average groundwater depth of 8.5 feet (102 inches - 42 inches <br /> �=60 inches}. <br /> �_Moundin Analysis computed o'n'Pages 7`and 8 indicates a small likelihood of any significant : <br /> g <br /> elevational rise in effluent mounding under the future disposal fields. <br /> Page -11- <br /> Chesney Consulting <br />