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<br />INTERPRETATION AND USE OF REPORT DATA
<br />
<br />SOQ-Vc"r Flood Event. The 500-yearfloodevcntis important in making the
<br />public aware that floods larger than the lOO-year flood can and do occur.
<br />Tne 500'year flood event can also be uscd for regulating high ri, kdevelop-
<br />mentswithinthefloOdplain.
<br />Table 3 lists the discharges and water surface elevations for the 10,
<br />50, 100, and SOD-year flood events at selected reference points,
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<br />Flood Frequency and DiSCharge
<br />The 10, 50, lOO..,nd500-yearflOOdevent,wereusedas the flood
<br />frequencies for this floOdplain analysis. Thus, thedatade'lelopedin
<br />this report will be compatible no! only for regulation purpose. and
<br />H.B. 1041 designations, butareillso for Federal Insurance Administrati on
<br />flood i,,,urancerate.tudie..
<br />These ~arious flood event. have an average occurrence of OnCe in the
<br />number of year. "5 indicated. Forex,lmple, the 100-yearfloodoccurs,on
<br />the average, once in a lOa-year period. and has a one percent chance of
<br />being equaled or exceeded in any given year,
<br />The particular uses for the various flood event. in addition to tho.e
<br />stated above are a, follow.:
<br />
<br />la-Year and 50-Ye..r Flood Evcnts. Informationreg..rdingtheselo"erfre_
<br />quencyflood, is especially useful for future engineering studies ,lnd land-
<br />u,e planning purpose. related to minor road sy.tem., minor channel Improve-
<br />ments, the lac<ltion of parks and recre",tlonal facilities, agricultural land..
<br />andappurtenant.tructure., For structures and uses of this type on the
<br />,mailer tributaries and In area. where the high ri.k of Hructural failure
<br />is economically feasible and the hazard to life and property nun exi'tent,
<br />lhc u,,,o, the iower frcquency tlooJ. may be considered,
<br />laO-Ye,n Flood Event, The 100-year flOOd event may also be used for engi-
<br />oeeclng dc.;gn purpose. "here a lower ri.koffallure than the 10-yearor
<br />Sa-yeartlood I,de,ireu. However, the most importaotuseofthe lOa-year
<br />flood event lies In floodplain designation and I,lnd-u.eregulat;<.>na"et
<br />forth ih the n.lte >tatu!es, The State of Colorado considers the. lOa-year
<br />frequency flood ~, the flood event to be u.ed in desl qn i nq and protect Ing
<br />struetuce. and dwellings for hum"n occup"Uon. Thprefore, many floodr);,in
<br />reguiat ions are based upon the 100-year flood. A 1,0, the are~ whl eh "auld
<br />be lnunddtedbythe IOO-yearfl<lodlndybedelineateda,anare""fn"te
<br />interest as .ct forth in H.B. 1041--tlle State', lan<l-u"" bili.
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