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where 6! SlrO = F'eal: flow from the ](:rir yr.ar- -:'4 hor.rr storm in CF3 <br />H = Drainage area in square miles (76.7) <br />p = normal. annual precipitation in inr_hes thra given <br />drainage area ( U) <br />7FJ7 .9='•~' <br />L! 1.trlr = 1.SEI X 16.7 X 3~r <br />Ll Ivr.r = 47.r:r,3 CFS <br />This amount: compares favorably with str-caam gage data glue in the <br />r_::i.sting permit. <br />E>;hibi.t ~: shows a cross-sect.~on u+ the =.trearr~ and lower bench <br />area. The stream channel can be apF_,rur.i.mat.ed r.rsinn a trapezoid <br />oi~ tt'rF~~ i~ollowiriq charact.erict~.cs: <br />F3ott.om widthlb) = 9.2 feet. <br />Sideslopes(Z) _ ~H:11~ <br />Av~:,ilable deptl-~ (t.o bottom of berm) D = .U feet <br />Crrannel slolre(s) = 4.1~% <br />Mannings n (gravel.-coh6le) _ .G2:; <br />The safe capacity of the strearm channel without encour'rte~ring the <br />berm is calculated rasing Manni.ng's equation: <br />G! _ ----- F: S H <br />n <br />H = cross sectional are:; = 4'.5.6 ft <br />I=' = wetter] F:,erimeter = 2~.6 fi: <br />Fl = A/F = ,...02 <br />I:;! = 882.6 CF ti <br /> <br />Trre e>:ist.inq channel ie. more than adequate to I'~andle ihr--~ llrl> year <br />-24 hour peal Flow. <br />t9ine Fan Discharge lnto lrrigation Systeur <br />Hny water discharge from the mine will be delivered into the <br />sediment. pond. the outlet of the pond feeds thca irrigation ditch <br />as shown on P1ap no. 1. <br />-Fhe crarrent confluence of ditches ad..iacent. to Fourau 1 e CreeF:: wi 11 <br />be filled i n wtier a ner..essary to i nsr_rre tl-~at all mine water <br />travels down the i.rr'igat.ian dl.tcr~. <br />6 <br />