Laserfiche WebLink
Asc-4 <br />Allow liquid volume for 2 - 10-year events 1.95 Ac-Ft <br />Reservoir Sediment Volume: <br />Use Universal Soil Loss Equation (USLE)with an appropriate <br />Sediment Delivery Ratio. <br />Ys = R•K•LS•CP•Dr = (USLE) x (Dr) <br />Ys = Sediment Yield (tons/acre/year) <br />R = Rainfall Factor <br />K = Soil Erodibility Factor (from Wishmeier, et al. <br />Nomograph for 107 ufs, lOZ S o%om, Soil Str. 3 <br />and Mod. Permiability) <br />LS = Length Slope Factor <br />CP = Control Practice Factor <br />Dr = Sediment Delivery Ratio <br />The sediment yield method and figures used are from "Hydro- <br />logy and Sedimentology of Surface Mined Lands", by C.T. Haan <br />and B.J. Barfield, except where indicated. <br />• SEDIMENT YIELD <br /> Tn/Ac/ Tons/ <br />Area R K LS CP Dr Yr Acres Year <br />Top 20 0.15 .115 0.90 0.20 0.06 2.70 0.17 <br />2:1 slope 20 0.15 15 1.20 0.35 18.9 2.98 56.32 <br />2nd level 20 0.15 0.12 0.90 0.25 0.08 4.96 0.40 <br />Bench 20 0.15 0.27 0.90 0.95 0.69 0.40 0.28 <br />2:1 slope 20 0.15 18 1.20 0.35 22.68 6.62 150.14 <br />1st level 20 0.15 0.13 0.90 0.30 0.11 2.98 0.33 <br />Bench 20 0.15 0.22 0.90 0.95 0.56 0.85 0.48 <br />2:1 slope 20 0.15 18 1.20 0.50 32.40 4.27 138.35 <br />Bench 20 0.15 0.27 0.90 0.95 0.69 0.86 0.59 <br />2:1 slope 20 0.15 I8 1.20 0.95 61.56 2.07 127.43 <br />Roads ~ Misc. 20 0.35 1.5 0.90 0.80 7.56 1.15 8.69 <br /> Tons/year 483.18 <br /> Volume of Se diment Delive red is: <br />• Vs = Ys (2000 lbs/ton) (1 acre) <br /> . 5 (62. bs ft ) (43,560 t ) <br />Substituting Ys into the preceding formula gives a sedi- <br />ment volume of 0.28 Ac-Ft/Yr. Use Vs = 16553 cu.ft; total <br />sediment volume for a 6.7-year period shall be 82,764 cu. <br />ft. (1.90 Ac-Ft) . ~:. ~. z <br />