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h=H+Zm=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 20 based upon the encountered clay loam at the 20 ft depth under the ELF and the well log discussed on Page 8. Therefore, it will be assumed that a boundary exists at 20 ft bgs, H=20 - 13(Highest measured water table depth)=7 ft. Long- term maximum (rise of mound is estimated at 1 ft. Therefore, h= 7+(1 _2)=7.5 Zm I A l4 Iv 1 KI )o.so 't i-o.so 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 = 1,586 gpd(From Max. flow volume calcs.,Page 12)=7.48 gals/ft=212 fe/day A = 1,900 ft(From filter bed sizing calcs,Page 16) C=Length to width ratio = 9,therefore,C=0.5922 L=95ft K=Using average vertical permeability as most conservative=36 min/in: 1440 min/day-36min/in=3.3 ft/day h=7.5(See above) n=Length to width ratio =9,therefore,n= 1.7793 Sy= 12% t =3,650 days(10 yrs) Zm =0.0661 x 280.4 x 0.0576 x 2.91 =3.11 ft It appears that the maximum mound height that may occur under the ELF filter bed is 3.11 feet. This would leave a distance of approximately eight feet between the soil/effluent interface and the top of the theoretical mound: soil/effluent interface =2 ft below existing grade+ 5 ft separation distance=7 ft below grade. The mound may rise to a depth of: 13.0 ft minus 3.11 ft rise of mound = 9.89 ft below grade; 9.9 ft minus 2 ft= 8 ft. For wastewater treatment (destruction of bacteria and viruses)to occur, the distance effluent should travel under unsaturated conditions through the soil environment is generally regarded to be 5 feet. Mounding Analysis was not calculated for the WLF since the flows will be significantly less than for the ELF. If wastewater flow volumes should change for the Office Trailer WLF, Chesney Consulting must be notified to assess groundwater mounding. 10 Chesney Consulting