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3. ABSORPTION AREA SIZING Note:Mound setbacks are measured from the Absorption Area. A. Calculate Absorption Width:Bed Width (2.B)X Mound Absorption Ratio (1.F)-Absorption Width 10.0 Ift x 2.0 = F 20.0 ft B. For slopes>1%,the Absorption Width is measured downhill from the upslope edge of the Bed. Calculate Downslope Absorption Width:Absorption Width (3.A)-Bed Width (2.6)=ft 20.0 ft - 10.0 ft = 10.0 ft 4. MOUND SIZING A. Calculate Clean Sand Lift: 3 feet minus Depth to Limiting Condition (1.C)=Clean Sand Lift (1 ft minimum) 3.0 ft - 1.7 ft = 1.3 ft Design Sand Lift(optional): 1.3 B. Calculate Upslope Height:Clean Sand Lift (4.A)+media depth (1 ft.)+cover (1 ft.)=Upslope Height 1.3 ft 1.0 ft + 1.0 ft= 3.3 ft D•34:Slope Multiplier Table Land Slope% 0 1 1 3 4 5 6 7 8 9; tO 11 12 13 14 15 16 17 Id 14 10 11 22 23 24 25 Upslope 11.0C12.911-83 2.75 2.68 2.61 2.54 2.4,4 2.42 2.36 2.31 2.26 2.21 2.17 2.13 2.09 2.06 2.03 LOD 1.97 1.95 1.93 1.91 1.89 1.87 1.85 BPm3 Ratio 14:1 4.00 3.65 3.70 3.57 3.45 333 3.13 3.12 3.03 2.94 2.86 2,7812.7012,6212-5512.48 2.9t 2.35 2.29 2.2? 1.18 2.13 2.tg 2.03 1.9& 193 Ladd Slee% 0 1 1 1 2 1 3 1 4 15 6 17 18 19 110 11112 113 114 115 16 1 11 1 18 19 T 10 21 122 1 21124 125 Downslope 3:1 3.00 3.09 3.19 3.30 3.41 3.53 3.66 3,80 3.95 4.11 4.29 4.48 4.69 4.95 5.24 5.55 5.88 6.24 6.63 7.04 7.41 7.93 8.42 8.93 9,46 10.02 Berm Ratio 4:1 4.00 4.17 4.35 4.54 4.76 5.00 5.26 5.56 5,88 6.25 6,67 1.14 7.69 8.29 8.92 9.5T 10.24 10.94 11.67 12.41 13.19 1394 14.82 15.67 16.54 17,44 C Select Upslope Berm Multiplier (based on land slope): 1 2.60 (figure D-34) D. Calculate Upslope Berm Width:Multiplier (4.C)X Upslope Mound Height (4.B)=Upslope Berm Width 2.60 1 ft x 3.3 ft = 9.0 ft E. Calculate Drop in Elevation Under Bed:Bed Width (2.B) X Land Slope (1.1))a 100=Drop (ft) 10.0 ft X 1 11.0 1 % + 100= 1.10 ft F. Calculate Downslope Mand Height:Upslope Height (4.6)+Drop in Elevation (4.E)=Downslope Height 3.3 ft + 1.10 ft = 4.4 ft Select Downslope Berm Multiplier G. (based on land slope): 4.48 (figure D-34) H.Calculate Downslope Berm Width:Multiplier (4.G)X Downslope Height (4.F)=Downslope Berm Width 4.48 1 x 4.4 ft = 20.0 ft 1. Calculate Minimum Berm to Cover Absorption Area.Downslope Absorption Width (3.6 or 3.C)+4 ft.=ft 10.0 ft + ft = 14.0 ft J. Design Downslope Berm =greater of 4H and 41: 1 20.0 ft K. Select Endslope Berm Multiplier: 3.00 (usually 3.0 or 4.0) L. Calculate Endslope Berm (4.K)X Downslope Mound Height (4.F)=Endslope Berm Width 3.00 ft x 4.4 ft = 13.0 ft M.Calculate Mound Width:Upslope Berm Width(4.D)+Bed Width (2.B)+Downslope Berm Width (4.J)=ft 9.0 1 ft + 10.0 ft + 20.0 ft = 39.0 ft N. Calculate Mound Length:Endslope Berm Width (4.L)+Bed Length (2.C)+Endslope Berm Width (4.1.)=ft 13.0 ft + 38.0 ft + 13.0 ft = 64.0 ft Comments: