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<br />
<br />Explanation of Flood Types
<br />
<br />Predicting how floodwaters will flow and
<br />how they will affect people's lives is a
<br />difficult task requiring eareful planning and
<br />response. Hydrologists estimate the
<br />probability or reeurrence interval of future
<br />floods by studying the past behavior of a
<br />stream and/or surrounding streams, Floods
<br />are often categorized aecording to their
<br />return interval (e,g, 1O-50-100-year flood).
<br />Eaeh flood interval is related to a pereent
<br />chanee that a flood may actually oeeur
<br />within a given year. A reeurrenee interval is
<br />the average frequency with whieh storms
<br />oeeur. So the 100-year flood is not
<br />something that will oceur at equal 100-year
<br />intervals, It ean oeeur in two eonseeutive
<br />years, or not at all in over 100 years,
<br />
<br />~.lt.
<br />
<br />
<br />again in 1995.1nsteadof(:iiUing itthe,
<br />I~O%flood,we callit thel()Oyear ,
<br />flood, to demonstrate the magnitude of '
<br />the flood moreeffective/y.
<br />
<br />Colorado state law requires that the 100-year
<br />flood plain be used for land use regulation,
<br />as the flood plain coneept provides a
<br />national standard for the National Flood
<br />Insuranee Program, It is eritical for flood
<br />plain residents to remember that floods
<br />greater than the 100-year flood event may
<br />oecur at any time and may also exeeed
<br />
<br />Pueblo Flood Hazard Mitif!ation Plan
<br />
<br />proj eeted estimates designated by the 100-
<br />year flood plain boundary. It is important to
<br />realize that it is difficult to plan in a cost-
<br />effeetive manner for a sizable flood;
<br />however, risk can be minimized using a
<br />eombined effort of struetural and non-
<br />structural mitigation.
<br />
<br />.'..:.....,.,.,.:.:,-..'.-..,.,.-.,,'.-..,..-.....--..,....."..'.-.....'...,.._....,.....',. ,.,',. ,'".,,'. '
<br />.. ...... ,._",_,_, ..,..,..,.....,.."..._,... ." -0- .........,_.".......
<br />,...:::.;...-.;.....:;..,.;.,_....,....,.,-.-:..:::,.,..........-:-........-.:... .....,
<br />" "___,__:,."" ""._.. .0 .
<br />" Fountain Creek reached a peak
<br />....0. .... .. .. .0 ..... .d .. ,,',..
<br />. "," '..---" ,
<br />, flow of apprOximately 11,000 cubic
<br />,feet. per 'second (ifs) , during the
<br />, ,June 3, 1994 Storm, . This peak can
<br />..beequatedroughlytoaflOod with
<br />..a$ year recurrence intervaL A
<br />
<br />:::/o:e:~:::t7:::tv:/~:~~ "
<br />
<br />.. , reach.abl!ut 45,000ifs, LikewiSe, a
<br />.' 100 yeari"jerval wauldreach about
<br />M;tJOO cfs. > > ' '
<br />
<br />.::.c.:,-,:..,..,_.,:..-.....::.....'.,.._..-.... '
<br />..,-.:-,...:...,..,...--.,......'.......-..-.......-.....-.'..,..-.".-...."
<br />...............,_.......'.
<br />......, -....... ....." ..--.....
<br />., ,.., ,,---- .
<br />."',' ,._..-..,.".......... ,,-'..'
<br />"'-.- """'--"""""-,--._--
<br />.-,- . ., -" "."" , -.
<br />.......,." ,..............-.....-..-::.,...,. "",...
<br />....................... .......--..---...-
<br />......., .......... .. '_.,'_.",.....,............. ......... .
<br />.... .....................-.......-...-...'...,.... .
<br />~St Charles; 1901- 56,000 cfs
<br />-Arkansas, 1921- 100,000 cfs
<br />, 4Iuerfaito, 1923~ 19;400 cfs
<br />" " ~Fountain, 1965-,47,000 cfs '
<br />---", "'-::~:," '" ., ,
<br />'~Chico Creek, 1965->50,9004s '
<br />
<br />7
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