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<br />INTRODUCTION
<br />
<br />BACi<:GRDUN:lINFORMf,.Tlm;
<br />3. DRAIl1AGEBASHlfEATURES.- The IIrkansas River originates in
<br />the central part of the Rocky ~~ntains near Leadville, Colorado. Its
<br />waters enter the ~ississippi R.vcr, approximately 20 miles north of
<br />~Gehee, Arkansas, after following a 1,460 mile courSe through the
<br />States of Colorado, Kansas, Oklal.oma and 1I.rkansas. Runoffi$,.eceived
<br />from one of the highest regions in North America. At least 2S Colo-
<br />rado peaks in the upper watershed exceed 14,000 feet in elevation.
<br />These incl~e Mount Elbert, the highest pOint in Colorado, at an ele-
<br />vation of 14,431 feet. Above Great Bend, Kansas, the total watershed
<br />area comprises 34,356 square miles, with 6,002 square miles classified
<br />asnoncor.tributing. Thernajor contributing subbll.sin area, consisting
<br />of 18,130 square milc.s, is controlled 286 miles upstream from Great
<br />Bend by John Martin Pam near LaS Animas, Colorado.
<br />4. ~hc ~kansas River is a typical torrential mountain stream
<br />until it ~erges from central Colorado's Royal Gorge Canyon, a nation-
<br />ally fa~ous scc~ic attraction with steep walls over 1,000 feet high.
<br />Bol~' the canyon, at about 5,300 feet elevation, the valley gradually
<br />grows wider and descends througilthe foothills to reach <0,700 feet at
<br />Pueblo,Colorado. fromPu"blothrougl'thef"rtileGreatPlainsregion
<br />to Great Bend, the rlVer is c~",racterized by a wide streambed with
<br />low bank~ "hat oecolsionol11y shifts der""" " L;<o",u, ",,11 u"""loped,
<br />
<br />SPECIAL FLOOP HAZARD Ih~O~~ATION
<br />ARKANSAS RIVER AND TRIBUTARIES
<br />GREAT B~~-:l, KA'1SAS 'to ':;OHN V-ARTIt-; PA!1, COLOAAOO
<br />
<br />1. GENERAL.- This report presents i~forMation on th~ flood
<br />hazard areas that adjoin the Arkansas River and its trihutaries
<br />from Great B~nd, ~n~as to John ~artin Dam, Colorado (see Plate
<br />A-I). Its contents appear as Appendi" A in the "Review survey
<br />for Flood Control and Allied ~urposes, Arkansas River and ~ribu-
<br />taries,GreatBend,KansastoJohnMartinPam,co1orado." The
<br />survey report proposes plans 0' improvenant and recomnends that
<br />local interests adopt and enforce nonstructural measures in cer-
<br />ta1n r"aches. These mea~ures would nini"'.i~e future damages in
<br />the study area from a flood expected to occur once in 100 year~.
<br />The guidance herein is designed to assist in the planninq anu
<br />adoption of ~uch flood plain ma~~gemcnt techniques, both before
<br />and after constructio~ of ~he ~ec~~nrlpd r~deral floon control
<br />projects, as may be most advan~ageous in establishing control
<br />over ~he co"""unity'~ fl00d pro"" lii"rl~.
<br />2. 8asicob]"ctivesof':hisreportllreto: (1) providcdcfin-
<br />itive flood hazard information on t~e area~ subject to inundation
<br />in amanneor easily understood by tho layman, (2) encouraqeoptitnurn
<br />and prudent USe of flood plain lands by providinq St~te and local
<br />agencies a factual basis for reducing flood d~mage5 and hazards
<br />through carefully con.id,,~cd, wcll*pl"n~."rl regulations governing the
<br />use of floodplains, (3) publicize "vailable infonnationon the use
<br />
<br />irrigated valley.
<br />5. Sl'REA.:.u'LOI>:CHIlRACTBRIS'l'ICS.- Streamslopes"aryfroma:naxi-
<br />ITumOf about 110 feet rer rnile in th" mountain reaches to 7.5 feet per
<br />",ile immediately belo.... JOh.l'- Mar~in Dam; then gradually decrease to
<br />~ess than 6 feet per mile near Great Bend. In addition to regulation
<br />by John Martin DdlT, natur~l stred~flow" ~re affected by t~ansmount~ln
<br />
<br />U~d ~~~~rd~ of t~c floc~ pl~i~~ i~ ~ ~~n~cr to cn~i~t thc ~upp~~t of
<br />private citizens and other concerned nonqovernmental interests; and
<br />(<0) reduce expenditure" on flood control projects for the protectio~
<br />of developmenb wl:ich .hould not h~ built ",.ithin tc.e fleod plains.
<br />
<br /><;l;"~,-.,;,,n~, ~to,.~'l~ "~".rvoi,-.,. irri'J~tion <liv"'r_"i"n~ and ,..~t",..n flow~.
<br />
<br />gro~~dwater ~i~hdrawa15, a~d power dev~lopments along the river
<br />ch4nn~l. p~rtin~nt drain~ge a~Oa~ and ma~imur., known discharge~ for
<br />the Arka~sas River and its tributarie~ are glven in Tahle 1.
<br />6. Past historic flc",,q', originat,ng on the Purg~toin~ ~iver,
<br />
<br />rount~in Creek, a~d other ~~jor ~ributdr'es in ~h~ upper Arkansas
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<br />A-2
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