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Floododaroaandfloodda"l<lgos-l1atersurlac:eprofilesfor the I "termed i~t" Regional and Standard Project Floods were deve loped for the length of the study reach using bac~ater COMputations by the Standard Step l!etOOd. The profi les, on p latp.s 8 through 10, ~now tho elevation of tho ~ater ~urtaces and water depths rolatlvo to the channel bed. Head losses at b ridges were clllcu lilted using "Hydrau I ics of Bridge W"ter~ays" puh I i shed by the U. S.Dep<lrtroentofCO':"l'!1crcfJ. The water surface elevations were used to dotermine flood limits on the cross sections and topogrephic ~DS and In turnthelloodboundaricswere loclltedontheaerlal photographs. The results are shewn on the flooded llrell",aps, rlatas 3 through 7. ^nindextothe lloodedareaplatesisonplate2. Representatlvecrosssectionsareillus- trated on plates il through 15. The cross sections shew grou~ elevations across the valley on both sides of theehannel anddapthsotcver!lankflocxJlng. Re/erence points, coinciding with the location of surveyed cross sections, are provided to locate tlood elevations at Intorvals along the river. The reference po Int locations are shCl<n on llooded ar!')a ""'~5, prof lies, and cross sect Ions lor beHer correlatiOl'l bei'~een drllW Ings. Tot> Ie 5 prov Ides data at reference point locations, locludlnc;distance fror"mouthand elevations for thestrf'am bed and the I ntcrmoo iate Regional i!ndStandardProjectFloc1s. Ab"aring is Drovided for orientation of fhe cross soction through the reference noint. F 100<1 elev~tlons for t,lO two large potentia I f loads elln be obtained Iron the profiles, cross sections,orrefcrcnce table. Forasocclflesituatlon where accuracy 0/ flooded area Is required, thG appropriate flood elevation can ~e found from one 01 the a/)ovo so~rces and that elevation located by survey on the llood plain will establish the flood I;...;ts. Photograohson pages 2O<lnd 21 illustraterotential fl<XXldeptns"tsrocified locations inthcstudyre<lch. I , I Figure II. Potential FloodHeights,Hlgt>.;ay23 Elridge,Bellvuc. Upst"e~m from Laporta, aroas subJect to f I cod 11"19 by large floods Qn the CaChe la Poudre River are largelv undeveloped, and used for cropland or pasture. Upstro,,~ 'rom Reference Point ~2 the left bank is r"K!stly bove Ilood level',. A f I~h hatcl",,-y Is locafed on the r;q~t ~,]nk , I , I ! , I I I , , I I Figure 17. Potontia I F loo:J lIeh,ht" Overl ~nd Tra i I P.Oa~ Bridge. Larorte. 20 "