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<br />FUTURE FLOODS <br /> <br />Tables 6, 7,8,9,IOand II enTitled "Flood Plain Reference Data, <br />Cache la Poudre River, HewlettGulch,H111 Gu!ch, Falls Gulch, <br />lO/athIlGulch,andUnnl;lroodGulch", respectlvely,presootsdlscharge <br />data used In this sTudy. <br /> <br />FloodS of tho same or larger magnItude than t~se that <br />have ocCurred could occur !n the fUTure. To determine the flood <br />potential of the study area, the IO-year, 50-year, 100-year, and <br />SOO-year floods were analyzed. The results of thIs analysis are <br />presented in this report as a means of demonstrating the effects <br />of large floods. <br /> <br />Tllble 4 <br />Cache 111 PQudre River Basin <br /> <br />Drain1lgel\rells <br /> <br />Location <br /> <br />Dralnaqel\rea <br />(Sq. mi.) <br /> <br />Discharge magnitudes for Cache III Poudre River floods <br />analyzed in this report were based upon IIn analysis of stream <br />gaging data at the U.S.G.S. stream gages locaTed about 10 miles <br />and9miles upstream and downstream frl)tl1 Poudre Park respectively. <br />Information on these stream gages was presented In table I. <br />Because of The lack of stream 91191n9 dllta in the immediate viciniTY <br />of Poudre Park, the Massachusetts Institute of Technology CatCh- <br />ment />'odel (MITCAT) was used to develop a hydrolO<jlc model of the <br />CaChe la Poudre River basin upstream from the mouth of fhe canyon. <br />This model was calibrated using discharge frequency relationships <br />established by the analyses of the U.S.G.S. stream gaging stilt ions. <br />Rainfall values used in the MITCAT hydrologic model were obtained <br />from the Preclpltatlon.Frequency Atl~s of the Western UnIted <br />States, Atlas 2, Volul'18 III, Colorlldo publ ished by the National <br />Oceanic and At!r.ospherk AdmlnlstraT!on in 1973. Soli Inflltrlltlon <br />rlltes ~re determinod using data developed by the Soil ConservaTion <br />ServlceMd fhe CoIOrlldo ShteU'llverslty Experl"'\ElnT Station. <br /> <br />Cache !a Poudre River <br />Upstream from falls Gulch <br />aownstream from falls GulCh <br />Upstrellm from Hewlett Gulch <br />Downstream from Hewlett Gulch <br />Upstream from HII I Gulch <br />Downstrollm from Hili GulCh <br /> <br />415 <br />416.3 <br />416,4 <br />439.4 <br />439.~ <br />44~.1 <br /> <br />Hewlett Gulch <br />"",'M <br /> <br />" <br /> <br />Hili Gulch <br />Upstream from Watha GulCh <br />DownstrElllffi from Watha Gulch <br /> <br />Mouth <br /> <br />4.3 <br />5.4 <br />5.' <br /> <br />Discharge mIlgnitudes for floods on HewletT Gulch, falls <br />GUICh,HillGulch,WathaGulch,andUnnamedGulchanalyzed In this <br />rOpOrfwereilISOdeveloPedusln<1MITCAT. Table4,entltled"Cllche <br />III Poudro Rlvor Flasin Dr"lnag.., Areas", presents basin drainllge <br />areils liT various locatlo'ls /lIons the Poudre Park study reach. <br /> <br />f'allsGulch <br />UpSTream from Unnamed GulCh <br />DownSTraam from Unnamed Gulch <br />/>'outh <br /> <br />1.1 <br />I.Z <br />1.3 <br /> <br />W"t"" GulCh <br />:Jouth <br /> <br />1.1 <br /> <br />UnnilmedGulch <br />/>'outh <br /> <br />.15 <br /> <br />9 <br /> <br />10 <br />