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..'~ <br />C RLCULRTION9 P'`~n ~ ~~~~ <br />~ . ~ .rr . n: rr np.l r.; ... <br />gTI FI_IL RTInN Nf1. 16 <br />Max lrnuum capac lty of the eight 36 Inch culverts at station 31{50 of the <br />IJOrthern No. ! haul roads <br />Eight 36 Inch CMP 's, 40 feet in length <br />Orn=CR 2GH3 Civil Engineering HandbooK, page 4-29, equation (54). <br />Om=Maximum cfs for each culvert <br />C=Coefflcent of discharge-C1v11 Englr~eering HandbooK, Table 6, page <br />4-40 = 0.64 <br />G=Gr avlty <br />H=Maximum Head = 1.5 feet <br />R=Rrea of pipe = 7.1 square feet <br />0rt.=0.64(7.1ft ) 2(32.2ft/sec)1.Sft <br />Orn=44.7cfs <br />Total Qm = 8 x 44.7cfs = 357.6 cfs <br />Peak flows for the 10 year 24 hour events <br />From Espey, Huston b Rssociates, Inc., Appendix A of the CMLRD Mine <br />Permit Applications <br />010 Upstream = 269 cfs <br />010 Lateral 21 cfs <br />010 Sed. Pond = 0 cfs <br />010 Total = 310 cfs <br />Therefore the culverts have an over capacity of 357 cfs - 310 cfs = <br />47cfs or 357cfs/310cfs x 100 = 115% capacity of the 10 year 24 hour <br />event. <br />Post reclamation assuming the removal of the sedimentation ponds <br />010 Upstream = 269 cfs <br />010 Lateral = 21 cfs <br />010 Reclaimed Rrea 10 cfs <br />010 Total 320 cfs <br />Therefore the culverts will still have an overcapacity of 357 cfs - <br />320 cfs = 37 cfs or 357cfs/320cfs x 100 112% of the 10 year 24 <br />hour event. <br />