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<br />the Cache la Poud~e Rlver j"s~ do"nst~eaOl [~o'" Fon Collins. Oth,,~
<br />tdlNt"ry flood ~l",ins 1n the plains ~e"Lon ,,~e 611bs~"ntlally llano"'er.
<br />The flood plains of Sheep Dr.,,", ,~nd !1os311 Cree;':, for ~,,","pl~, aVHa~e "
<br />Ie'" hllndred feet ~ide o~ le5~.
<br />
<br />,lood Depths and Velocities. Det~iled ftood plaLn studies co~
<br />pl..ted p~ior to this stlldy ,~~e aV3ilable only fo~ the Caelle la POlldre
<br />Rt vcr in the plaills and f o~ the Poud~e Park <IN-a ill the m<"Jn~ain8.
<br />Available info~matto~ indicates ~jo~ floods in the plalns reache.
<br />would range fro", 8 tol5 feet ieepabove the channel bed. Channel
<br />vclocHle9 r11.nge f~o'" 2 to 5 fe.et per aecond. Depth$ on the overban;'
<br />a~e genenlly 5 feet or l~s$, altbough occaaionally deepe~. Overbank
<br />'",-locitie. are gene~ally about 1 to 2 feet per second, but velQcitie9
<br />could be higher at certain points.
<br />
<br />lI"llvue and Lapon~, (e"ch of which had a populatton of less than L,OOO
<br />1n 1970), Fan CoU1ns, and Greeley. Th~ lOO-year flood ~laln of the
<br />Cache In Po~d~e River fro~ the canyon mouth to the SOlltb Platte River
<br />cove~s aboLlt 12,700 acre.. 'loat of the town of lIelU'1gton, with a"
<br />estimated popul,Ition of 691 in HaO, Ues "lthb the Hood phln of
<br />3oxelderCreek.
<br />
<br />Adjacent to G~eeley the flood phln is 1llOderately developed; it
<br />containa farms, paature, feedlots, g~avel pit9, and co~erci"l and
<br />residential development. A la~ge nutllbe~ of buildings are located in
<br />tbe flood plain on the northeaat dde of G~eeley. In addition,
<br />ral1~oad9, state and local ~oads, and publ1c ~tll1t1e. are subject to
<br />Hooding.
<br />
<br />In the nan"", ",ountain canyon at Poudre Pa~k, ~he 100-yea~ flood
<br />averages abo~t IS feet de_ep abov" the "tr~a,.bed aod the 500-ye...~ flood
<br />average. about 20 feet d"ep. Channel "elocltie" ~_"n be tS t<> 2~ feet
<br />par $econd or greater wUh overba'lk velodr{e~ of abollt 5 ~o 10 teet
<br />per second. In general, floodwater 2 o~ ",ore f"et deep and flowing at
<br />a velocity of 3 or :nore feet per se~""d could "a" Uy ""eel' "dlllts fr"Ol
<br />their f",,-t, thus C~"dt1ng definite d~nge~ of inju~y o~ d~ownlng.
<br />
<br />In the Fore Collin. a~e", development 18 generally I11llUed to
<br />Laporte, to an area at the U.S. Highway 287 cro.,ing no~th of Fo~t
<br />Collins and ~o an 11.rea nea~ the COlorado Highway 14 c~<>s$ing east of
<br />the dty.
<br />
<br />FLOOD HAZARD POTENTIAL
<br />
<br />A detailed flood da"age analy~ls WM _de for the co=unitlu of
<br />LaPorte, Fort Collin$, and G~eeley. .able 8 summarlze" data on the
<br />fl""d ha~ard potenti..l at these ~~b.;n aUa$. 0"=g"3 arc for ~u~ld~nl>$
<br />...nd contents and do not Include da""'g". t<> !\t~"ets and u' Uitle. o~
<br />,,,,,ergency and cleanup coata. Prl"" levels are Lnde"edtoS'pt"",ber
<br />1980.
<br />
<br />This section p~e8~nt~ information on the developtllen~ that la
<br />""hje" t ~o flood h'lzdrds.
<br />
<br />In th., plain. gecrtOn or the l>asLn, ",ost <>f the flood pldb la:1ds
<br />a~e u"eJ for irrigated or dry c~o;>l"nd, p.'stura, .H rangeland. Tb~re
<br />ls, hO>l"v"r, SO"", ~and ,nJ :~ravel ."bioH and the~e 'Ire nUel',",;"" hiS"".'Y
<br />and rallro.1d "trllc~llre". p"rtln,," of "e~~ral 'Hb"n H-""'~ .,,..' '1tso
<br />l~c..~ed >li,h10 the~" flo.,d 1',,1In8. A:""~ tlw 1lIdL1 51e", the.<" lac1,,~c
<br />
<br />Ihe rapid develop",ent of land a~ound Fort Collins '1od Greeluy ~ay
<br />~as,,1t. in new flood haz,,~d are"s. SpecifiC araM. of concern Lnclude
<br />the Sp~ing Cr~~k and FossIl Cteek flood pl~tn. near fort Coll{n., the
<br />flood plain of Sheep Dr...'" near Greeley, and ~he r~th~r undefin~d flood
<br />plain of the watershed nea~ the city of ~indsor.
<br />
<br />PLAIOISREGIO!;
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