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F7decreasing mound may form under the disposal field creating saturated flow conditions and istance the effluent must travel under unsaturated flow for effluent treatment to tion developed by Finnemore and Hantzsche (1983) is used below to predict themum rise of the mound: h=H+Z,n=2 where: h=distance from boundary to mid-point of the long-term mound, in ft H=height of stable groundwater table above impermeable boundary, in ft Zm= long-term maximum rise of the mound, in ft Substituting known and estimated values for the variables, we find the following: H=The height of stable groundwater above an impermeable boundary is estimated to be 5 ft based upon the measured standing water in the boring. Therefore, it will be assumed that a boundary exists at H= 7 - 5 (Highest measured water table depth)=2 ft. Long-term maximum rise of mound is estimated at 0.5 ft. Therefore, h=2+(0.5 2)=2.25 ft Zm 1 CI (4 In 11Ctt'o.5n ' t i-a5. where: Q=average daily flow in ft'/day A=area of disposal field in ft' C=mounding equation constant L=length of disposal field in ft K=horizontal permeability of soil in ft/day n=mounding equation exponent Sy=specific yield of receiving soil in percent t =time since the beginning of wastewater application in days Substituting known constants for the variables,we find the following: Q =425 gpd(One-quarter of Sunday ADF found on Pg 9 averaged over a typical week)_7.48 gals/ft=57 ft'/day A =6,500 ft(From mound system sizing calcs, Pg 15) C=Length to width ratio constant = 2.6,therefore,C= 1.135 L= 130ft K=Using average vertical permeability as most conservative= min/in: 1440 min/day= 15 min/in=8 ft/day h=2.25 (See above) n=Length to width ratio exponent =3,therefore,n= 1.76 Sy=7% t =3,650 days(10 yrs) Zm =0.00995 x 458 x 0.0786 x 2.12=0.76 ft From the calculations presented above,the maximum mound height that may occur under the future mound system is 0.76 feet. There remains a sufficient distance for effluent treatment to occur,which is generally regarded to be five feet, between the soil/effluent interface within the mound and the top of the theoretical mound above the highest elevation of the water table, as demonstrated: 5 ft=current distance between existing grade and water table minus 0.76 ft potential rise in water table= 4.24 ft. 4.24 ft+(0.33 ft of mound peat material + 1.0 ft of sand/drain rock)= 5.6 ft distance the mound system will provide between the sand-drain rock/effluent interface and the potential water table rise. I 6 Chesney Consulting