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<br />1~N".:snGAnCr<S AND A'iALYSlS <br />Inter::e.JO.etation and Use of..Report <br />A. Frequency and Discharge <br />The 10-, SO-, 100., and 500-year flood events ar.. used as the flood <br />frequencies fot' this flood plain analysis. Thus, the data developed in <br />this report will be suitable not only for regulatiOt1 purposes, and H.B. <br />1041 designation but also for Federal Insurance Administration flood <br />insurance studies conducted by the Federal Emergency Managenent Agency. <br />These varicus flood events have an average occurrence of once in the <br />number of years as indicated. For eX<Wlple. the lDQ-year flood occurs. 00 <br />the average, once in a 1OO.year period. and has a one percent chance of <br />being equaled or exceedod in <my given year. <br />The particular uses for the varicus flood evente in addition to those <br />stated above are as follows: <br />lQ:Y.~r and 50-Year Flood Events <br />Information regarding these lower frequency floods is especially <br />useful for future engineering studies an:l Land use planning ?-Irpvses <br />reLit",J to ruinor ro<tJ "yst.,.ns, minor cflmn,d imprOV.:l'",nlS, ch., location of <br />parks and rt!creational facilities, agricultural lands, and appurtenant <br />strncturf"s. Tho? use of the l~ frequencey flco:xlB may be cOll'Jidered in <br />plarming flood prevention projects to protect agricultural areas, or other <br />property where risk to life is nota factor. <br />lOO:.>:'':.~~Fl.....,u E"""L <br />'The lOO-year flood event may be used in lieu of l~r frequ,;ncies fur <br />engineering design plll1>os"s v.here great"r s"curity from structur" failure <br />is desired. <br /> <br />HOW€ver, the [')()~t important lIEe ot the LOO-year floOO event lies in <br />flood ?lain managE'ITII.>nt and land use planning as set forth in the !ltate <br />statDtes. The State of Colorado considers the lJXJ-year frequency flood as <br />thE' flood event to be used in designing and protecti~ structures and <br />d\.iellings for rnnan occupation. Therefore, all flood plain regulations <br />are based upon the 100-year flood. <br />SOO-Year Flood Event <br />The SOO-year flood event is useful in making the public aware that <br />floods larger than the 100-year flood can and do occur. Just because a <br />person is liVing above the lOO-year flood borndary cioea not m<'1ll1 that he <br />is cor.lpletely safe frClll flooding. The 5Oo-year flood event can also be <br />used for regulating high risk developnents within the flood plain such as <br />nuclear f'OW"r plants, or the storage or man.rfacture of toXic or explosive <br />materials. <br />B. FloodElevatioo <br />Flood crest elevations for the 10-, 50-, 100-, and 5OO.year floods. <br />all determined at each cross section. may be found in Table 1 "Flood <br />frequency-Elevation Brld Discharge Data". Figures. 1 through 10, show a <br />graphical representation of high water elevations ilt typical valley cross <br /> <br />secti.oru;;. <br /> <br />Water surface elevations computed at each cross section were <br /> <br />used to prepare flood profiles, sheets 1 throtlgh 37, <bich ah"" the <br />streillllbed elevation in relation to water surhce elevations for the <br />10-, 50-, 100-, and 500-year freq'-"'llcy floods. <br />The flood profiles may be used in areas where controversy arises o.rer <br />the IOO-year Hood bomdary shCWl on the Flood Plain Maps. Since th" <br />flOOd profil",exhibi.tsgiv"" the~ter b'Urface devation at a specific <br /> <br />'0 <br /> <br />11 <br />