Laserfiche WebLink
DCT-15-1999 16 29 FROM STEIGERS CORPORRTION TO 3038328106 P.04i04 <br />Culvert C-2 <br />Trial configuration -18-in-diameter CSP, which has a rated flow, Q = 5.70 cfs <br />5.70 cfs > 1.58 cfs, Q culvert > Q drainage, trial culvert is adequate <br />Ditch D-6 <br />Trial configuration - V-ditch, 2-ft-deep, 2:1 side slope, unlined, assumed velocity = 3 fps <br />Overland flow time for Area 6 (0.46 acre}, which contributes to Ditch D-6, is 16 min <br />The ditch flow time: <br />t =length/velocity = 136 ft/(3 ft/sec X 60 sec/min) = 0.76 min <br />Total flow time = 16 + 0.76 = 16.76 min <br />Rainfall intensity: <br />For Region 6 <br />I =(210)/(16.76+ 26) = 4.91 in/hr <br />For Region 7 <br />I =(77)/(16.76+10) = 2.88 in/hr <br />I average = 3.90 in/hr <br />The dischazge for Area D-6 using the Rational Formula: <br />Q = (0.50) (3.90 in/hr) (Q.46 acre) = 0.90 cfs <br />The rated discharge for the trial ditch using Manning's Equation: <br />The properties of a 2-ft-deep, 2:1 side slope ditch: <br />A=bh=(2ft)(4ft)=8ft' <br />R=A/P=8ft'/8.94ft=0.89ft <br />The slope of Ditch D•1 is 0.007'% <br />Q = (1.486/n) A R "' S "' <br />Q = (1.486/0.025) 8 ft2 (0.89 ft)"' (0.007)"' <br />Q = 36.81 cfs <br />36.81 cfs > 0.90 cfs, Q ditch > Q drainage, trial ditch is adequate <br />Culvert C-3 <br />Trial configuration -18-in-diameter CSP, which has a rated flow, Q = 5.70 cfs <br />5.70 cfs > 0.90 cfs, Q culvert > Q drainage, trial culvert is adequate <br />Suaunary of Kvaerner Calculation <br />Picesnce Site Diversion Difch Sysmn <br />Technical Revision Mining and Rectamadon Permit <br />TDTRL P.04 <br />