|
<br />
<br />VELOCITIES OF FLOW
<br />
<br />In lll,' sln."m r<'"dws ,l",li,,J, MHaJo["
<br />,"<,Iociti"" of 110w durinjo[ a H)O-y<,ar flnoel
<br />would be a~ ~hown in Tabl.. 5.
<br />Velocity o( nuw during a :;OO.)."ar flood
<br />would h<, s!il(htly higher lhan durinjo[a l()(j.
<br />,.,':.r n..od. In sh,'d now' ~lrea', "l'l~itie"
<br />wouldrang..rrom 1.:lr....tpersecond,lnsom..
<br />localizedstream....ach....forexa:nplearound
<br />l...ndsor dow"str,':,", frm" natural orman
<br />made ob'trllctiun~. ,.dodt;, of now ..oultl
<br />sij(nifi,';>ntl,.,'xe,...dlh""eshown inl'ahk5,
<br />
<br />
<br />\\' a t<' r flo\\' i n jo[ a t ;\ r~' l,' of r, feet per S",-,"o nd
<br />or Jo[r<'atl'r will er(J(!o.'streambanh and tile f;ll
<br />arounll bridj(e abutment", and is..apableof
<br />tJ':.n"I"".Linj( larl((> rocks, l.arJo[e amnunt, of
<br />~~Ta,-c1. ,;ami. and silt ma,. be transported I))."
<br />W~Her nowing at a rat,. of'; fl'et per serond.
<br />Wat<'r nowing at about 2lr~t per &>eond Ilr
<br />les.~ will d"IX),;it ,and, ,ilt. and nood born..
<br />debris.
<br />
<br />TABLE 5
<br />
<br />AVeRAGe VeLOCITIeS OF FLOW
<br />100.YEAR FLOOD
<br />
<br />Stream
<br />
<br />Yelocity
<br />(f....t per ""~(lnd)
<br />MaIn Channel Overbank Areas
<br />
<br />Yamp" Hiv<'r , 2
<br />Furtifit'atiu" C,.,'<)k , 2
<br />Br(Jth~I.llln Gulch 6 2
<br />I'in~ WrlJo['. GIIleh " 2
<br />("~d"r Mountllint;ulch " "
<br />
<br />FLOODED AREAS
<br />l'he approximate limilsofinundlltionlhat
<br />would result from a 5Ol).year nood on the
<br />,trpams under titu,l)" arc ~h"wn on P(at~ 1,
<br />which is an ind<'K to mllre dctai\~d maps
<br />~ho"'ingtheareMthatwouldbein\lndatedby
<br />lOO'llnd 5Ol).ymrl100d,;(Plau,s2.27).A1Sll.
<br />tl", lOO.,,~ar not"l ha.. own d"lineated Il"
<br />larx~ scale Ulpographic maps (I inch'" 200
<br />f<.~t) that ar~ on file in th~ Moffat Count;-
<br />Planninll: Dl'partment. As may b,' set'n from
<br />the flooded area. plates acrompanying this
<br />report.thl'IOO-yearfloodllnthl'Yl\mpaRivl'c
<br />WQuld e.."enlial1y inundate the entire vall~y
<br />
<br />floor. exccpt far wine ~islands.. of higher
<br />ground. ~'loodwaters would extend fro'" y. w
<br />)I, mile from the river..nd ralll:!"uptoSf<"'l
<br />deep in th<>Il,.erbank area~. One.hundredycar
<br />nnoeling along Fortification Cr,-,~k WQuld
<br />clO!I<'ly parallel the streamway aOO,.(> 10th
<br />Street. and would generally beconfinerl to the
<br />streamway, exc(>pt forsnml',hee\ flow li.rea'
<br />below 10th Street Overflow (rom the lOO-ye~;
<br />flood "n I;rolh..rt<>n Gulch closely paral\els the
<br />streamwaj' above thelIighwar 13.789crtlSS-
<br />ing,whprp ilfflMouland breaks out to the
<br />south w comminl;"lc with Fortification Creek
<br />
<br />. Shoet n_ i. b,olld. ,h~lIo,," G....t1~"d fIood;"~ ~."<..II~' t.... th~" 2 rod d..,p, Sh"", fIo" n",-,,_h"~ '"
<br />~ha'.('(""'.('d. by ~n~.<<I"t"bl. ""'" p'''M. I.. ....a!<" "",fa"" .t~\.>tLO" ,,""~n".Uy ,n""".""~n' ~r '0\' w.k'
<br />.u,l"" ol'~'3""" of lluw .I~n~ lh,ad,:,...,""t,..."''''~'. ano i. alf""'"I!,,i,"..,.I;. L~- manm..l, _..I ".",r-~I b.";,.,,
<br />to t'lOl< :n t~o ."" nood,~
<br />
<br />24
<br />
<br />I I
<br />I I
<br />
<br />I I
<br />
<br />I I
<br />
<br />I I
<br />
<br />I I
<br />
<br />I
<br />
<br />
<br />I
<br />
<br />
<br />I I
<br />
<br />I
<br />
<br />I
<br />
<br />I I
<br />
<br />I I
<br />I I
<br />I
<br />
<br />I I
<br />
<br />I I
<br />
<br />I I
<br />I I
<br />I I
<br />
<br />n'Kxlwat<'r in a common pondinlZ ar..n.1'h.,
<br />I'rineilml"....a,o(flo...diT'lfal()I\l<'i'ineltid~
<br />l,ulchconll'rioel'ondin>:area,;al lh.. Highwa.'.
<br />.10 and lli;rhway 1:1.7~9 eros.~inl(S. A larK'.
<br />.het't f1o\\' area would ,'xl,'nd from the
<br />fJj;rhwli.)'" 1:1.789 er",,~injt wIIlherly tu the
<br />fJr.xxll'l;\inoflh,.Yallll'alti,.(>r.Theprincipal
<br />ar..a.~ofHJ<).yea,.floodinl':on C..darMountain
<br />l:ukh coml>rise sh....l fin\\' we~t of the ,trt'am
<br />in IhO' ,'ieini~,' "f the upper Cl'l),;sing of
<br />Ilijo[lIway:_I,."i."nd''''~I.b~ltk flow w theeasl at
<br />thelo\\'ercI'o",inJo[ofll;jo[hwal':I')~.J\r><mdinl!"
<br />area \\'ould ""rUI. al Lh.. upslream sid,' of
<br />Ilijo[hw;\; --In. and ~he<:II1QW Ihat cllmminjfl,.~
<br />with Pine Ri,lIte Guk-h sh\~.t flow w"uld oecur
<br />tlown~lreltm from Ilil':hway 40,
<br />In jl:encral. the&OQ.)'ear ll<xxlwQuld follow
<br />the sam(> patterns"~ the IOO,year f100d.out
<br />inundation would exl(>nd farther from th..
<br />~tream channels and be substantially deeper
<br />in some 10<:1ltions.On t'llrtificationCreck,500-
<br />,'e'lr f1ootlflllw~ wlluld hr<>ak nut to the east
<br />upstream from th<' lIighway 40cr"",inK to
<br />inundate hi~torically flooded ar,'ag around
<br />andea.terl~.llfthefairground,. Fh.e.hundred
<br />,'('ltrsheetn...wnnoelinp;inthe..entrals"ction
<br />Ilf the city would extend in a wld..ning fan
<br />ghape lrom the vicinity ol 10th Slrcetonthl'
<br />nurlh lothl' railroad...n lhesouth. and from
<br />Hanny Strcetlln the w,,,, to thc creek 011 th!)
<br />ea_1. Al'proximately ""eity block> I"".thr>f
<br />\'ICOOQ. Way wO\lld be .ubjeet to.hL,<,t now
<br />flooding.
<br />In WULl. the IllIl.y..-,.rn"odwnuld inundate
<br />approximately 1I.800ll.cres.of,,'hich 1lI,150
<br />
<br />FLOOD DAMAGES
<br />A 100. Ilr5Ot).,.('ar flO<X! in the Ccaigarea
<br />wouldraus,:.ub,;(anti..II.e<itle"ti"l.commer.
<br />ci"l. <tod inrlll~trial damaj(P. AWicul\ural
<br />105:'t'S would also be significant and would
<br />O<:CllC primarily in thcootlllmlandsll.lllnKth(.
<br />Yampa River where crop, and li,.el\t<l<:k
<br />would bedestro,.oo; farm and caneh improvc-
<br />mt'nts.espt'cialb'irriRlI\ionI\Yl\tems.wouldbe
<br />damag~tl: and subtantial e05b would be
<br />incurred W rt'.ture crop and pasture Iand~
<br /><"O,.eced with silt "nd debris or damajl:<,J by
<br />em.ion. P.esidcntbl losses woulJ include
<br />dama,::e W foandatim\s. exterior al\d interior
<br />'A.:.\1,. floors. hrnishlnf;::). :.:-:d upp\i;\nces
<br />(c,pl'ciallyappl;ancesandhcatin;rS\.,tl'rl\sill
<br />
<br />acr"" aN' agcieultuc:.l, ~t5 Iteres are residl'tI.
<br />tin!. 200 Iteres ace commerciaHndustrial.
<br />l.100 acres arC streamwa~.. and 25 acres arc
<br />rights.of-way.!tshouldbenotedlhllts.llofthe
<br />f1noded areas shown Iln Plates 2-27 mav not be
<br />inundated at the sam.. time becau;e flood
<br />I'roducinge<>nditionsintllevariou5tributllO'
<br />\\"alershed~ would not n~ee,;saci]" occur ""n.
<br />currently. Shallow flooding ilt"l'ners.lly less
<br />than 6 inches deep) may oceur beyond the
<br />flooded areas shown. The depth of f1llw in the
<br />channels and adjacenlnooded area.~alnnll: th~
<br />otream, and streamways under study can be
<br />determined {rom the watcr surlace prllfiles
<br />shllwnlln l'illtes28-44.
<br />The flooded area, shown on Plates 2.27
<br />reflect unobstructed channel flow. Ice jams
<br />rould alter the patternsshll\\"n.especially
<br />..l...ng Fortificatilln Creek. Therefore. the
<br />possibilityllflcejamsaggravating the flood
<br />,ituationshouldooxivenCllnsiderationin
<br />using this report. Areas historically flooded
<br />due tll ice jam;; lire generally descril>cd and
<br />iIIuslrated in the (l(>wspa.p.er articles and
<br />I'holop:raph. rovering th.. 1921 and 19~7
<br />floods (pajfes7.12 and cover phlltllgraphs), It
<br />must be p<linted out. however. th..tsignificant
<br />ehanK~'S in the alignm(>nt Ilf Fortificalion
<br />Creek have been made since 1947 and its
<br />carrl'ingNtpaeityhasincrea.ed.thatchanjf(>s
<br />instreetsa.ndhixhw"",'shs,"ch,-,-"nmadc.and
<br />localized cllanges \ll topograplly ha,.e
<br />""rurred. Th..rdoce, anl' fulure f100dinl::
<br />resultinl': lrom lce jams would not necessarily
<br />aflcctart.as identical wtht:l:.<einundated from
<br />tllis t),l>e of nooding in the pa,t.
<br />
<br />ba.'<t"ments8ubjeetw filling with nn...Jwatl'r).
<br />Outliide im>>rownwnt>; such l'8 lawl<$ a",1
<br />gaMrn.would bedama~ hy d"po!li" o(
<br />sand and silt. Comm..reial los.,<es would
<br />indude struclural amI ''1I11ipml'nt damalle:
<br />tl'mporarylt>Sllll[busincss: losl\of invenlory
<br />stllred on lower floor. aml in basements: and
<br />th..rosl.l<tJfdnnup, repair. and rettllratwn.
<br />Railroad track, l'",bankmenl. and induslrial
<br />sirlings would be suhject w damage from
<br />inund;\ti"n. and slreambanb <<'Iluld bt,
<br />eroded. Access to \":J.rio~ "r..""""u:<I be ~ut
<br />off forperil)(lsr3n,::inj(from;1 rcwhours t.llJ.
<br />few d~)'~.
<br />
<br />2;;
<br />
|