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<br />GLOSSARY
<br />
<br />FtoodCrc.t.
<br />at a given
<br />Flood Frcqu~ncv. (See Probability.) The averag" r~cunence int~r-va! of
<br />aped!ie di,chargea or water ~tage~ which cause flooding.
<br />
<br />The maximum
<br />location.
<br />
<br />stage or elevation reached by the waters of a f!~d
<br />
<br />eack",atH Effect. The ri"e in "urface eley~tioll of f1(\\<in~ "'~ter "pst",,,",
<br />from and as "result {)f "n ob'lt;ructic)Il to fl"".
<br />
<br />Channel. A natural or "rtifieill! ..."tHcOUr"C of ~~rc"pUbLc ext~nt with
<br />deUnite bed and blink" to confine and conduct continuo\lsly or period-
<br />ically fl~wing water.
<br />
<br />Flood Peak.
<br />cation.
<br />
<br />The maximum Instarltaneous dl"charg" of aflooo llt a given 10_
<br />It uaually occurs at or near theUmeof the flood crest.
<br />
<br />Cloudburst.
<br />in areal
<br />thunder,
<br />
<br />^ 8udden and e~tremely heavy downpour of rain th"t is small
<br />extent; of short duration; and may be accompanied by lightning,
<br />"nd.tronggustsofwind.
<br />
<br />floodplain. An area in and adjacent to a stream, which area is subj~ct to
<br />flooding as the result of the o~~urrenCe of a 100_year flood and whi~h
<br />area thus i" "0 adver"e to past, current, or foreseeable construction
<br />or land ua" as toconatltute iI GignifiCl1nt hazard to publ1c health and
<br />SAfety or to property.
<br />Flood Profile. A graph showing the reletionship of water suTface elevation
<br />to location, the latter Benerally expre8sed as distanc~ above mouth for
<br />Il strelllll of water flowing in an open channel. It is generally drawn to
<br />8how surface elevation ror the crest of a apecific flood, but may be
<br />prep8red for conditions at a given time or stag~.
<br />
<br />Conveyance Capacity.
<br />
<br />a. Channel convey"nce capacity is the rate of dLscharse, in cubic feet
<br />p~r sccond, which can flow in a water course with the water surfa~e
<br />not greater than the height of the channel banks.
<br />
<br />b. Ftoodway conveyance e.~pncity is the rate of discharge in th~ ovcrflo"
<br />portion of the floodway which can pass through a specified area
<br />at depths and velocities govern~d by the hydraulic dimensions of
<br />thefloodway.
<br />
<br />Flood Sta~e. The stage or elevation at which overfiow of the natural banks
<br />of a aUe"", or body of water begins in the r~"ch or area in which the ele-
<br />vation is measured.
<br />
<br />Designated Floodplaln. The are" de8lgnated.:ls a floodJ,lain by off Ictal acUon
<br />of the board of county c0lNT11s_,ionersor city councilwUhtbepriorcon_
<br />currenCe of ch~ CoLorado \/aCer Conservation Board.
<br />
<br />Floodway Zone. The channel of " str~am and tho.e portion, of the adjoining
<br />floodplaln which arc reasonably required Co carty and di~chargc the flood_
<br />watcr~ of " lOO_year flood. It 1.. the de"i~nated floodplain le~~ th~n
<br />the low hazard zone, if any 5<lch low hazard ~Onc he" been identified. 1f
<br />any such low ha'.:Ird zone ha~ been IdentHi~d, tlwn the terms "design"ted
<br />floodplain" and "rloodway 7.one" ,.hall be con.idered as bet,,!; sy"ony,"o"~,
<br />
<br />Floud. An overflow on lands not Ilormally covered by "ater and that"re u," ed
<br />or usable by m~n. Flood. h~ve two e8"ential charactt'daUc., tbe inun_
<br />dation of land ia temporary: and the land i~ adj~c~nt to ~nd lnund~r~d by
<br />overflow [rom a river or stream or al\("",an, lake or <>ther bodv of "tanding
<br />water.
<br />
<br />Norm"lly a flood is conSidered as any temporary Tise in 8treamfiowor "tage,
<br />but not the ponding of surface water, that r".ult. in signifie~nt advers"
<br />effects in the vicinity. Adverse ~ffecta may include damageS from ov~r_
<br />flow of land arnas, temporary backwater "ffects in sewers and local drainage
<br />channel", creation of unsanitary comUtions or other unfavorabie oituations
<br />by deposition of materials instrea'''channetsduringflood recc s.ion",".e
<br />of ground water coincident with increased streamflow, and other problems.
<br />
<br />Intcrcocdiatc R~gior."l ncod. .~ typc ,,;, n-:,,,d, i,.d,,<ting th~ "~t~r ,,,~fu~
<br />eleyation and territorial occupation thcreof, which C8n he expected to
<br />occur at any timc in a givcn ar"" baRed upon recnrded historical pr e_
<br />clpltatLon and other valid data, hut with an average Btatistical one
<br />percent chance of beln~ equalled or e~"eeded during anyone ye.:lr. The
<br />term is used interchangeably with a one percent flood or one hundr~d
<br />year flood. (See definition for IOO_year flood.)
<br />
<br />Left Bank. Thc bank on the left atd~ of " river, 8tre"llL or ",,n('r cour"~
<br />aa the ob~~rv"r looks downstream.
<br />
<br />Flood,IOO_Year. A type of flood, includlng the water "urfacc olevationand
<br />territorial occupation thereof, which can be expected to occur "t any time
<br />in a giv",n ar,,~ b""ed upon recorded historical precLpitatlon and ot,h~r
<br />valid d,~ta, bllt with an averag.. statistical one perc{,rtt chartce of betng
<br />cqualhd or exceeded durirll\ anyone year. The term L~ u"~d int"rchangeably
<br />...tth a one percent fload or Intor,,".edlate Re~ion~l Fl.ood. (S~" d~fLnitioll
<br />rnr !nt""""'"llat,, Regt..nat,'l""d.l
<br />
<br />TAl" H~~~rrt Zon~s. That STe" of the floodplain in which th" waters of a
<br />lOO_yc"r flow will Hot liu"i<l a llL",d.m\lITl d~pth gr~ateT than one ~nd on,,_
<br />half feet.
<br />
<br />l'robabi tI tv. The annual chancc of "ccurTenCe of specLflc hydrologic "v~nt",
<br />"uch ~" ,ainfall "v~r " spt'cified an'" "r 1""" dl"eh.~r"e "t a ~redfie
<br />location e~preaH,d in percent, e.".. SJ. representing on~ eha:\c" tn 20 of
<br />
<br />);
<br />
<br />10
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