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f Substituting known or estimated constants for the variables, we find: Q = 180 gpd(Estimate based on 12 people on-site x 15 gpd-See Pg. 13)- 7.48 gals/ft'=24 ft'/day A = 1,380 ft2(From filter bed calculations based on 180 ADF from Sewage Standards) C=Length to width ratio � 4,i.e. 19 ft wide x 74 length,therefore,C= 1.1348 L=37 ft K=Using average vertical permeability as most conservative= min/in: 1440 min/day 19.2 min/in=6.3 ft/day h=2.95 (See above) n=Length to width ratio z4,therefore,n= 1.7716 Sy=8% t =3,650 days(10 yrs) Z. =0.0197 x 175.76 x 0.0751 x 1.784=0.47 ft It appears that the maximum mound height of the water table that may occur under an effluent disposal area is 0.47 feet. This would leave a distance of approximately 6.73 feet between the f ground surface and the highest theoretical groundwater mound above the elevation of the water table. 7.2 ft minus 0.47 ft = 6.73 ft. For wastewater treatment to occur, the distance effluent should travel under unsaturated conditions through the soil environment is generally regarded to be 5 feet. Consequently, a filter bed with a depth of 1.75 ft(soil effluent interface 1.75 a below grade)would provide the minimum distance of five feet(5 ft+ 1.75 ft= 6.75 ft). In the Finnemore and Hantzsche paper, they discuss three options to consider as potential methods of reducing the mounding phenomenon. The first is increasing the size of the disposal field. The �. second method is elongating the shape of the area covered by the disposal field, which has been done in the length to width ratio calculations above. Thirdly, operating the field intermittently should decrease the mounding effect. If it is determined at some point in the future that mounding effects are preventing proper effluent treatment and disposal of effluent from any proposed project, the area designated as the 100% replacement areas may have to be activated. The reserve area will have to be designated when a project is proposed. E. SURFACE WATER INFORMATION Storm water management must be an on-site retentionbasr h trstbe stnl tesl with minimal excavation and built-up embankments. This isA6'�mainta n a five-foot separation distance betw the floor of the basin and the depth to groundw .._._ _bR,..._.....a-F--1 Groundwater dilution effects can only be truly discerned with groundwater monitoring and modeling. According to a scientific paper authored by Shaw and Turyk(1994), reduction of nitrate concentrations in groundwater can occur primarily through dispersion, or by percolating rainwater, or a water source including effluent water recharge. Climatic Data: Rainfall versus Evapotranspiration NLS§3.2. It is generally and scientifically acceptcd-that when precipitation exceeds evapotrans- piration(Eto), deep percolation of surface rainwater may occur. Evapotranspiration refers to water evaporation that takes place both at the soil surface and transpiration by plants. 8 Chesney Consulting