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<br />Report of ."he ReGion6-1 Directo:.',
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<br />"oout 2-1/2 mi.les, a m'lxi",um width of a[,proximatoly 1 !:lile, "nd a
<br />total cal,;acity of 8,650 acre-feet to -!lhich sur0j1f'.,.se would Rdd 13,150
<br />f,-ore-feet in t;~1e event of the desibn flood.
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<br />F1.'lIlctic:n..c.l c::l!.x).cities 0::' tl:e :.....eservoir would be as follows:
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<br />Irriguti on,~ . . .
<br />Fish and wildlife
<br />Sedimentation ':!:/
<br />Total oS . ~ . .
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<br />jl..cre-feet
<br />7-;000--
<br />900
<br />750
<br />8-;550
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<br />Bra:r.iel Da!11
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<br />10. T'.'o desib'~ and cost estimp_teG hc.-ie teen prepared to meet t.h,"
<br />requirements of separate spillwaj' de3is;n flood estimate.s" Adequate
<br />storm data are In.cking, hence that pro0edu)"e Vias adopted to obtain
<br />esti~r!.ates upon which foubseq1.-;ent eI1~ine8rhlg and economic studies could
<br />be b3.se~ The 13.r!i,cr estimS.te, vjr~ich h~.s beeT;, adopted for this report
<br />h1 or-e'er to use the pro1l[lb18 maximum cost, is b~.,sed upon a design
<br />flood poc.k of 25,000 cfs with D. flood vol'.une of 17,800 acre-.fee" in
<br />24 hourso 'I'he smaller estimate vias bUGed upon a peak flow of 23,000
<br />cfs "ith a flood volume of 6,000 acre-feet in 18 hours. The final
<br />dosi,:;n probably "liould be betv~een tho~e tV\lO extremes.
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<br />n. The rolled-earth dam would rise 68 feet above the st,'eam
<br />bed and 95 feet abovo the '.'ottom of the cutoff trench, The crest, c,t
<br />elevrction 4,178 feet, would he.ve c. len:;th of 1,160 feet, and a width
<br />of 25 foeta The 3 to 1 "pstree.m 810;oe "Iould be ;,rotected by 3 feet of
<br />riprap to tho 20-fcot term c'.t elevation 4,140 whereupon the slope ~'ould
<br />be 4 to 1. Tho 0ntire base of the Qam would be stripped and would
<br />have c. cutoff trench to bedrock -"ith tho centorline 15 feet upstroam
<br />from thu a..-ds, A gravel blanb,t \Vo'.,ld be pIc_cod undor the riprap a!"'.d
<br />3. Cir8.in provided in the dO\'Jl1Gtreo.m too~ The left end of th'9 (l_nm
<br />w,l'J.ld liD-VC a rOT"Cr'Se curve in the r.linomcnt to 8.ccorr%od.o.tc D. spillwu~r
<br />chute thl'ough tho':) dn.rn"
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<br />12. Tho pot~nti.al aClln weuld conte.in 384,000 cut-ic y.:c.rds of
<br />mo.t,oria!., Imporvious material i:1 sufficiont quantity is ottain"tle
<br />8.t t~1C sitco It YJQuld "l:C ncccsso.ry to hc.ul the pervious mc.tcrial [lr.d
<br />the r.r;2:rOl;ate for t.ho concrete structures from the North Phttto Ri-J"cr
<br />nc::-'.r PIC:nrJ; Ncbrn.skn" ::1 c.ist:"l.ncc of ::..bout 9 miles,] Rock for ripr::-~p
<br />is cl'ro.ilr,blc from Table i.~otU1tain, c.bout 4 miles ncrtr.wnst of the site,
<br />or from qt:.o.rrics ncar Guernsey, WyominG., This latter source r.'Quld
<br />involvo 0. rc.il C\nd truck hewl of about 50 milos,
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<br />wY Sp:::..cc 1Js~'.blc for irr:i..gi.:.tion sto['(li'i.(' unti: fi ~J:(]. '.;':::':' sediment.
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