<br />Hi"u!J'y 10 thl' Col'l'Jdo, fle,',ui(Hl in the
<br />drJinalleb.-in ranges from Jbout 13,000 feet in
<br />he.,dwJtef JreJ'to Jbo"t 4900fe"t at the mouth
<br />of Ih"riv"r,,,,.rDeh., The,lrNmdrJinIJ"Oul
<br />475'quaremilesattheupme.mltudylimil,565
<br />'quare m,I",atMontrmc, and 721 ,quJremilel
<br />Jt lhe d<lwn<trNm ,tudy limit, Its tributary
<br />drainage" bound..d on 11", w..st by Ih.. ~an
<br />'V1igu.,lR;'''fb",in,onth..,outhby,th..Anim.-
<br />Rive. b."in, and on Ihe,'a't J"d north by Ihe
<br />Gunnison River b,,,in.
<br />The widely varied topography of the
<br />"'gion--mount,i" range" high plateau. Jnd
<br />me,a" _"d IhecompJralivelyhighl.,'ncompah_
<br />greValley-creat"sdi\tinetand'Jrie<iclimalie
<br />conditions, Low humidity and mild yea'-round
<br />dimaticcondiliomgenerallyprevailduetothe
<br />protection afforded by .urrounding high
<br />mountain peaks, which tend 10 amact moi'lure
<br />fwmp",sing'torm., butal'oprotectthe"lley
<br />IfOm high velocily winds. HOw"""', t..mpera_
<br />tureoften drop. below lfe"l;ng in wintera"d
<br />
<br />NATURE OF FLOOD PROBLEMS
<br />
<br />Flood,inthelludyareagenerallyr".ultfrom
<br />rap;d melting 01 the m<JUnlJin.nowpackfrom
<br />.lbOUI themiddleof,'V1aythrou~h"",IYluly;'nn
<br />frorn general 'ain,torm, that normally OCcur
<br />trom July through October, Snowmelt floodmg
<br />.,cha,acteri.ed by moderate peak flow.,I..g..
<br />,olume, long duration, .nd "'arked diurnal
<br />t1u<:luati')rl 01 flow, Snowmelt runoff may
<br />O,CJ,inn.lly he angm,'otedhy rain, R3inftood,
<br />ore chJracte,ized by high peak ttow, ot
<br />moderale yolume and duration, Floodi"~ i,
<br />more Severe when .ntecedent ,.inf.1I h.,
<br />
<br />FLOOD HISTORY
<br />
<br />Allhough lheMonlro,e.Olalhea.e.l has,'
<br />long history of flooding,ddinil;'edalaonearl~
<br />floorl ,'yenl. are limited, LJ'ge flood. a,,,
<br />known to h,l1ie occurred in the l,;ncompah~re
<br />V.lllpydu,inglhel.,tcentury,Pri".loiIS
<br />wttlemenl in the t81lO'" Chipeta, wile of th"
<br />UlelodianChie!Our.Jy"t.lled,heh"d.eenlhe
<br />Uncompahg'e Valley Jt Delta "flooded from
<br />bluff 10 bluft." In lune."JJuh 1884.'"pid
<br />meltin<\ 01 'l def'p ,n'''"pa<k.nd "on"urren'
<br />~enefal fJin ".ll,ed w,de'p'ead flood,ng along
<br />pOrliofllotlheColorJdo.l"dGunn'lonRive'l,
<br />
<br />rile, to over 90" in ,ummeL Ave'''ge annual
<br />me,n teml,,,"lure, rJng" from 35" to 64',
<br />""ormal annu.I"iinfalla'''''.g",about9inchf'',
<br />R.lin occurs throughout the )'ear, with th.'
<br />,mallestamollntinluneJndthelargestamount
<br />in Aug,,'t, Ave"se annual ,nowf.1I i,.lmo\1 30
<br />in"hes, in Ihehigh hNdw.terregions, normal
<br />annual p."eipilat;on.verage.almo,t45 ioches_
<br />ann'K,ur;mo;lly."nowthatu'u;JIlYJc"umu-
<br />lat'" iotoatleep ,nowpack,
<br />Veget.llion in the '.liley, where ,till uod,,-
<br />lurbed bv agriculture, and on the lower
<br />mountain slope'cofllislS01 narrowle.lcollon-
<br />wood and Ru"iJ" olive; .hrubs and b,u,h",
<br />,uch al willow, wildro.",.lnd bulfaloberry; and
<br />n"liyeg'J"e"lnthehighermo"rll;Jin()u,a,e3s,
<br />vegelJtion include. an underslory of n.llive
<br />gr''''''; willow and a YJriety 01 berry ,hrub\;
<br />.nd sta,,<I, of quaking "pen, dwarl juniper,
<br />l'ngelmaf1 Spruce, and 'ub-alpine fir. Much 01
<br />Ihear<'JaooyetimberhneisbJrrenandrocky,
<br />
<br />flooding in "",io",.r"",, th"IYI'",ofpropeny
<br />involved, and the kind,oldam.geincurrecf,
<br />Record, ,how that, line.. the turn of the
<br />centu'Y. nol.ble high flow, occurred on the
<br />IJncompahgfe Ri,er in 1921,1927,1938.1941,
<br />1944. 1947,195i,197),a"d1975,Thcl.rge.t
<br />known fl""d, e,tim.ted peak Ilow of 5,140
<br />
<br />cub;c feet per ,econd, occurred "bOul min_
<br />lune, 1921., a relult of ,nO,,"01..it, Th" onl}'
<br />notable cloudburstllood ol,ecord o(Curred in
<br />July 1923, Peak ftow' of the larger hi,toric.1
<br />flood, on the Uncompahgr" River are ,hown in
<br />hble1,
<br />
<br />TABU 1
<br />PEAl( FLOWS Of HISTORICAL HOODS
<br />
<br />Flood
<br />Yed<
<br />
<br />Pe.~ Flow (cubic leet pel second)
<br />Ddt. Cage: I Date Colon. Cage: I Date
<br />
<br />1921
<br />1927
<br />1938
<br />1941
<br />1944
<br />1947
<br />1957
<br />1975
<br />
<br />r"'ulteninS.lIUfar<>dgroundcoodiliom"'lhe
<br />ground i. frozen and infiltration i, minimal.
<br />Com'eni"" tyre cloLJdhur<t "",m" ,,,m,-,lim...
<br />lal!inl\ for ,,'v,,(.] hour;, can be exp"ned to
<br />occur in the Montrose-Olathe 'egio" du""g
<br />the .umme" Runoff from Ihe,.. '1"'01' is
<br />char.lue,ized by hil':h pe.lk diKhargc, .horl
<br />duralion, .nd ,mall volu",,,, Uu" 10 lh".mall
<br />areal ".I<'ot of cloudh"", "",m" they would
<br />have Illtle elie" In the ,tUf]y Ml'J unless they
<br />o('curredconwrrenlly with r"l'id '''ownwlt or
<br />runoff from &..n",al r.in,
<br />
<br />FI,,~ nuL uu"""din~
<br />'ht'm""'~, ',,'p,>;, ,I,;!, ik>w,
<br />
<br />',OMch
<br />
<br />It is prob.lbl.. Ih.lt ,imilar lIood <o,,<.1il;oo,
<br />exoswd along th,-,Un,nmpJhgr..RwerheCJu'"
<br />the 'nowpack WJ' unUluall}' deep dnd V,"Ned
<br />v"'v l.Jrg...r<,., thaI Yl'ar,Alw, itwa"talt'u in
<br />th<' Ma~ 17, 1884, editton of lh.. 5,10 luan
<br />~rn'rt'((nr tl\"1 "Ihe LJ,,,,,,mpah8re " ri'irl8
<br />rapidly' and a" o,,,rllo.... i, feJ<l'd," Det.liled
<br />new. COVNJg<, of Ilood,ng in thow YNr<,
<br />h"..,,,-,,,.wa,pra<.ti,,,II,.rl<,n,'.i,(e"ldu"lothe
<br />rurJI,lndi",I,l1t'dn.llU"'otth,.tloc><fedar"a,,
<br />~"me k"owledg~ "r fluud "",,"I; wa'; 8ainc'tI
<br />from "\,c'....i!ne,, "ecounts "f the C'Xtl'nt of
<br />
<br />,
<br />
<br />,
<br />
<br />lun13-14
<br />)'."'28
<br />lun22
<br />
<br />Jun29
<br />lul4
<br />
|