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i• i ~ ..--. • • III IIIIIIIIIIIIIIII
<br />~• '~ EPlGIFlEEFtIf~G & ~UF~VEti'IF,fG COI'.iPAi`Y
<br />BOX G74 443 DODGE DL•LTA, COLORADO. ~1G16 303-~74-7593
<br />~~~.c-. ~--- ~L~..=~c~c_r,_.. ~....~.~-.a:x.-r~v_+.,~~» ~..r_ i..r.. -._ r.,.~rn :~:rv vr.--. ~.-~vu~_ u :.cs~. ~
<br />10179
<br />October 22, 1901
<br />47cstcrn Associated Curd Curp.
<br />Suite 2300
<br />410 Seventeenth Strr:n.t
<br />Denver, Colorado UI1"I_U2
<br />ATTN: L•7illiam 5. Talc
<br />Re: Oluc Ribbon 11inc, 11r:nrlr ;LnbiliLy, VinlnLiun fit-10
<br />In response Lo ynur letter dnl.crl .7ul.y ?0, t'/lit Lo the 14LR rr:gnrding
<br />drainage an Lhe above referenced bench, •we cuhmiC Lhe fo]]owing
<br />design recommcndaLions for your cun:~idurnliun. Surface runoff,
<br />or accumu.lalion of c+oler un Lire hcnch itsnlf uhnuld be handled
<br />with surface ditches much as you pre:;r.nLly have Lhe.m constructed.
<br />A gradient should hr nccunip]iohud from Lhe lnl.cr:;cct.ion of Lhc
<br />bench with Lhe higlnanl] :;loping outward t.u a 1,u.ir~L nppro>:imaLely
<br />15 to "LO feet from Urc oul.sidr, ]iniiCs of Lhe hcnch. Another
<br />yradicnl should bs consLrucLcd from Lha I, r:rm ;clung Lhc outside
<br />edge of the bench bock lu•.+:rrd Lhc interior of Lhu bench Lo intersect
<br />the gradient rnentioncd nbuvc. This o-rill crc;rLc a very shallow "V"
<br />ditch that twill convey runoff gcncrnlcd un Lhc hunch Lo appropriate
<br />ditches. The drainage, "V" ditch, will he only :, few Lcnlhs of
<br />a foot deep and wi 17. purnii L uper:rLiui, of c~lu ilrnicnt and vehicles
<br />with na discomfort Lo Lhc ulreraLar nr in~l,,~irment of Lhc operability
<br />of Lhe various piccns of erluil,incnf.. P:uLc LhnC Lhc bench is not
<br />flat. At, ur ucar, your IrrcccnC ]unduut I:rci.liCy, the hcnch has
<br />a break in ;lope Surface r,,rL~:r north of Ihi break in slope floo-rs
<br />northerly, and ;;urfnce t:nlur cuuLh ol` Lhic point floo-rs southerly.
<br />lake advantage of this nnLurnl brcnk in clul,c to convey Lhat portion
<br />of surface r+atcr on Lhr: north porCinn of the hcnch Lo the 10-inch
<br />pipe presently innlnllcrl fn the exisf.ing dr:~inagc. South of Lhe
<br />break in the bench :;.lope, all r,nLer can he conveyed Lo Lhe exisCing
<br />ditch located an the inside :.boulder of ynur nccr,ss ro:.~d.
<br /> •
<br />Our rccomrncndnLiono fur Lhc rlr:rin:,gc ::y:;lcm Lo he inr;Cnlled along
<br />the outer region of Lhc mine hcnch, .in nci'n rrlnncc rr.iLh your July 20,
<br />1981 letter Lo 14LR, inc ludr.s :;cvcra] r:r~gir~r: cr.ing dr:Cails. 47e have
<br />prepared a drawing, whi ch is enr.lo:;r.d, Llurt shores surface drainage
<br />as proposed, nn n:wunicd l.iur, r+hr,re Lhc fill inLur sccis Lhe natural
<br />slope, local.iun ^f the prul,urcd rJrniuagu Ir cnch, and a cross-
<br />scctinn and prof.i lr: of Lhu I'rn, n;tcd dr:~i i,nil c Lrcr~ ch On LhaC dL':IY+l ng
<br />we have recunsl.rucLed ;r n :~:,•;uwed cnnLunr li ne for the ]ur_nCiun of
<br />the original hillside.
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