Laserfiche WebLink
1-3 <br />TASK 24 FINAL DRAINAGE CHANNEL CONSTRUCTION 100 YR STORM <br />Ditch <br />Design <br />Flow <br />(cfs) <br />Freeboard <br />Capacity <br />(cfs) <br />Length <br />(ft) <br />Slope <br />(%) <br />Design Xsec Area/ <br />Design+ Freeboard <br />Xsec Area (fk2) <br />Manning's <br />Velocity <br />(fps) <br />Exca tL%q r t c <br />Volume(*; ui d <br />�a �F� <br />A <br />4.4 <br />8.5 <br />100 <br />2% <br />3.0/6.0 <br />2.8 <br />600`414ftnWt <br />B <br />10.6 <br />17.3 <br />330 <br />4% <br />4.0/7.5 <br />4.3 <br />2475 <br />Fabric <br />C <br />4.6 <br />5.5 <br />350 <br />1.5% <br />1.0/4.0 <br />3.7 <br />1400 <br />None <br />D <br />1.5 <br />2.7 <br />770 <br />4% <br />1.0/3.0 <br />2..7 <br />2310 <br />None <br />E <br />4.6 <br />5.2 <br />190 <br />14.5% <br />3.0/6.0 <br />5.8 <br />1140 <br />Ri ra <br />F <br />4.4 <br />6.9 <br />35 <br />42.9% <br />1.0/3.0 <br />6.9 <br />105 <br />Ri ra <br />Totals CF 1.2Swell /27 = <br />297LCY <br />Manning's n for ditches A, B, C, D, = 0.025. Manning's n for ditches F_ & F, (riprap) = 0.050. <br />DITCH SIZING <br />• DITCH E & F DESIGNS WITH RIPRAP <br />:1 <br />Ditch C <br />Ditch D <br />%1.0 1.0 <br />r P0 ---I, <br />211. SIDE SLOPE <br />4.75 SQ. FT. <br />2:1 SIDE SLOPE <br />1 .0 SQ. F7. <br />COST ANALYSIS: <br />Excavate 319LCY with Cat 307C. $193 Total time = 3.1 <br />Using RS Means Site Work for riprap placement: Xsectional area for riprap = 4.75 cf/lineal foot of channel. <br />(Channel E + F) x (Xsec) = 260ft x (4.75fF) = 1,235cf, - 46cy. <br />Machine placed costs = (46cy) x ($27.45) - $1263. Rate of placement is 62cy/8hr, 46/62 (8hr) = 5.9 hours. <br />Cost of riprap = ($35/ton)(1.425tons/cy)(46cy) = $2294. <br />Filter fabric costs: 90'x 8' roll =$38. 6"staples/roll @ $7. Ditch B @ 330'/90'x ($45) _ $165. Assume 8 hrs installation <br />• time. <br />Total costs: $3915 Total time: 17 hrs <br />