<br />FlITURE FLOODS
<br />
<br />Only in rare instances has a stream experienced the lar-
<br />gest flood possible. Severe as the ma><Un\lll\ known flood may h<1'lc
<br />been en a given stream, it is generally accepted that a larger
<br />flood will occur. Larger floods have been experienced on streams
<br />with s.Unitar geographical and physiographical characteristics as
<br />the cuehar..s ll.iver. Severe storms will undoubtedly cccur in the
<br />cueharas watershed to cause future floods that .",il1 surpass known
<br />histeric floods. Discussien ef future floods in this report is
<br />limited primarily to those that have be~n designated as the 100-
<br />year flood and SOO-year f1cod, however, 10-year and 50_year flood
<br />
<br />data aro presented.
<br />
<br />Definitiens of these future floods arC found
<br />
<br />in the Glossary of TerTIUI sectien of this ""'l'Ort.
<br />
<br />Flood Maqnitude and Their ~requencies
<br />Standard hydrelogic and hydraulic methods were used to
<br />determinethemagnitudecfflccd"efth..seiectedretu.-nfre'luen-
<br />
<br />oics.
<br />
<br />Hydrelogy data was develeped f~orn the r..sults of ~ f~nquency
<br />
<br />analy"i~. ,.lew f~equ..noy pa.~illl\ot.,~s were duvelcped f~em "Manual for
<br />Estimating ~lood Cha~acte~istics of Natural-Flew Streams in Oole-
<br />
<br />r"de." P""k dischargesef the 10-. 50-, 100-, and 500-yedr flcodS
<br />at selected locatiens along the CUcharas River are listed in Table
<br />2. Floods largcr than thc SOa-year flood are possible, but the CQm-
<br />bin<ltlon ef facters necos"llrr to produce such larg<, flowH would ''''
<br />""eremely rare. The Corps ef Engiu"..rs' IIEC.l "~C1I'-Il/lekwc,~"r """'-
<br />puter pro<j~am was u.."d to develop tho flooded "redS and flood l,roIi 1,'n.
<br />TheloO_yearfr<lquenoyfleodisdefined<ls<,floudhavin\l
<br />an average frequency ef occurrence en the erder ot once in 100 years
<br />at ad""ignatoo 1ccation, although it may eccur in <lnyyeilr andpos-
<br />
<br />sibly in successive years.
<br />
<br />It canbc "-,,pressed in tennsofpercen-
<br />
<br />tag" to aveid the possible inference ef regularity of occurrence.
<br />Thus, a floud with a 100-y~r recurrence interval would have" en<'
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