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<br />The oily of Fort ColUn~ has a "pe~[~l <)rdinance "hich require..
<br />regul~tlon of flood ph.in l.~nd "~,,. Fort GnUj", alsQ h~s ~n on~.~ln"
<br />" "
<br />program for acquiring flood plain hnd~ 'OC publ~c uS" .,,,Uvl:ies such
<br />~s p~rk, and recre~tlon fields.
<br />
<br />FLOOD HISTORY
<br />
<br />1'his sect (on present" general data on p"st ft<Xlds and d,,~crlptions
<br />of <elected floods to show the n4tllreQf the fl""d pfoblc",.
<br />
<br />Lari'n<>r County has e:lacted flood plain reguL.clons
<br />
<br />to ,,,pplemenc
<br />
<br />its ",Hli:>l; ordinancc. The regulatl<'" d..f1n~s allowable l.."d u~e$ !~ a
<br />"Flcod"a)' Dhtdc~" and a "Flood Frlng~ District," StrlIctures for
<br />hurn.1<ll1abitaUorlareprohibltedlnth,,"Flood"ayOtst(lct." All
<br />HfuctUNS constructed in the "flood Fringe Distrl~t" 1llust be ahoy", the
<br />regu14tory flood el.v~tton.
<br />
<br />CACllE LAPOUDRE RIVER BASIN
<br />
<br />~eld Coun~y flood plain land ~se r~gulations in~lud~ differ~nt
<br />reatrictians for a defined "flood"ay", "low hazard district", and
<br />"flood prone tracts". $tructur". are llOt alto"'ed lntlle "flood"'3Y" but
<br />""'.y be con,tructcd in the "low h"zard dtetrict" "'Hh special rnstric~
<br />tions. Special 8t\ldies are i d ~ ~
<br />req\lre uy tnedevelopnrof "flo{l.dprone
<br />tracts" to iden-'t.v ~,,,.,," " d '
<br />, . " ~,,~ He ~"e .QPIO.~"t 'adY lr.po"a. County
<br />"ubdtvLsi"n-,"',' ..
<br />. "u ~ ~ons "'G<J,"r~ t"e con. tr<Jct ion of d~te"tlon yond"
<br />i"..r",," of _n... d'''.,' .
<br />~ q ,,~w~. _ .~rment to ""sure ~"at develop~~nt will n~'
<br />
<br />Stream capaciti~s on the Cache la Poudre River range from about
<br />5,000 c"bic fect per second (c.Ls.) near Fort Collins toaboClt 3,000
<br />c, f,s. at Cree ley. Streamflow r~cords fro," the r.s. Geological Survey
<br />(USGS) gaging 8tation~ on the Cache la PO<ldre Rtv~r <Jp.tream from Fort
<br />Collins and down"trea~ from Greeley, supplemented by data collected by
<br />the Colorado State Englneer, indlcate that 27 floods of varytng severl-
<br />ty have occ<lrred sinc~ 1882 in the viclnlty of either For~ Collln~ or
<br />Greeley, or both. In addition, major floods on the mda stem are known
<br />tn ha"e occurred in Jun~ l8~~, June l86~, a.nd May 1876; however, peak
<br />d1.charge estimates for these flood. ar~ not available. Peak dis-
<br />charges for historical floods since 1882 are sho...n in ~able 4.
<br />
<br />!ner~"~~ ",-,noff.
<br />
<br />In addition to flood. 00 the mal" He"" it is lono",n that flooding
<br />occurred due to runoff fro", 8"",-11 canyona io the Fort Collln~ "rea
<br />duri~g 1 through 4 September lY38. High di.charge~ occur,ed on 31 Jelly
<br />19]6 on some minor tributar1es in the foothills region of ~he Cache la
<br />Poudr~ R1ver basin because of heavy ralnfall that caused ,he Big Thomp-
<br />.on River flood. Localized flash flooding occurred in Lari~~r ~nd Weld
<br />Countles on 24 and 25 July 1977 due to heevy thunderatorm rainfall.
<br />
<br />FLOOD FIGHTI~G ,~~D EMERG[~CY SVACUAT!OK
<br />EOleq;..nc.y actions in the ev~nt of a flood in the study reach a~e
<br />coord~na~{'d through ~he (:ivl1 Ode"5'" offlce" in Ladmer C"l"'~j alld in
<br />Weld County. T:,~~~ officE'" c()(}rdin"t~ ~"l",ral d15a"ter 3~tjvities.
<br />
<br />Ihe Dm,vcr '''eathp-r ~ervt~~ PoncaH -~ffi~~ (WSfO) af thc "a~l<>nol
<br />'~e,1'her ~er'J\te (:-I'~S), und~r the NatloMl ()cealll~ ~nd At"'osphe'l~
<br />Ad",1:113 ~rat io" (~QA.\), provides gene r" 1 fl,,~h-f load w,rnt <lg,-..
<br />
<br />Local streamflow record~ extending back to 1904 were obtained by
<br />
<br />th" ~"l1 C"n;;"rvJ,ticn Scrdcc d~"i"g its "t"d!~q nf th.. 1V>,,~ldp-r Cr~ek
<br />
<br />water~hed. Ihe." records indicate that ~ome flooding occurs in the
<br />
<br />.....ter3hed every 2 years on the average and that large flo"d$ occurred
<br />O~ Boxdder Creek In 1904, 19.09, 1922, tQ,O, \933, 1937, 1941, 1~4i,
<br />196\, l~~J, 1%", l%i, and 1%9. I" <lay and JUM 19,6, :wo .tor"'"
<br />calL~~d S~6"O() la J"o:a~e .1nd :~O"<; four Uvc. in ~he '~ellhgtDr. vldnity.
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