Laserfiche WebLink
"" -~ Ms. Linda Limbach <br />Area <br />Wetted Perimeter <br />Hydr. Radius(R) <br />DD-5 DD-6 <br />.42 ft.~ --2,0 ft.z <br />2,0 ft, 2.93 ft. <br />.21 ,68 <br />.- Using Manning's Formula for Velocit "- `"~'~ <br />Velocity = (1.49/n)*(R)2/3 *(Slope)~/2 <br />_. Velocity(DD-5)= 46.56 * ,35 * .4 = 6.5 ft,/sec <br />Area = Q/V = 9,36cfs / 6.5 ft./sec = 1.44 ft.2 - <br />Velocity(DD-6)= 46.56 * ,77 * .32 = 11.47 ft./ses <br />Area = Q/V = 24.Olcfs / 11.47 ft,/sec = 2,10 ft. <br />These give the cross-section area of each ditch which would be necessary to <br />convey the flow of the 100-year/24-hour event. More accurate sketches of the <br />ditch cross-sections might allow more accurate determination of WP and R. <br />In our phone conversation, you said that you had calculated a peak flow of <br />about 21 cfs for the Pinyon-Juniper area, which is relatively close to my <br />calculated peak flow. From the refuse Dile itself, however, yours is 6.21 vs, <br />my 9.36 cfs. Use of CN 82 (as opposed to 89) for the pile could account for <br />this difference, and is in my opinion too low for an unreclaimed refuse pile, <br />If you have any additional questions about these calculations, please feel-• - <br />free to give me a call. <br />Since/re~/l/y/J~, {~~J <br />V W ~ 1 /, / r <br />William B. Crick <br />_- Reclamation Specialist <br />WBC/scg <br />~- cc: Jim Stevens <br />_. _. 3649E <br /> <br />