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<br />Ob"tru~tia~~ to ,loodflow
<br />Tho affact of obstr~otion~ dus to bridges ~nd their
<br />~~pro~~h fills hee been ds~cribsd in prsvieua peragraphs. In
<br />th~ vi~inity of the Lowall AVsn~s bridge, brush ~nd othBr debris
<br />d~~p~d in tho flGodw~y ~ould obstrk~t the ~h~nncl locally and,
<br />during a ~~Jor flood, coule seriously cloy bridgs wut~rway o,Bn.
<br />ings downstra~m of this area, ther~by aub8t~ntislly incraesing
<br />flood depth~. The sanitary fill in the vicinity of 18th Stteet
<br />ie o~ obstruction thot would also incte~~s the depth of flow.
<br />Additionally, lend fill that has been placed downstream of the
<br />C~nvsr and Rio Grands Western Railroad bridge pertially blocks
<br />the west ends of ths 11th Strset bridge and th~ Denver and Rio
<br />G~ande Railroad bridge. in effeot, this blockage contribute.
<br />to the depth of flow at hoad loss of tho fut~re floods as sho~~
<br />on the ~ater surface profilss by reducing the flood.carrying
<br />capacity of the channel.
<br />
<br />Dam shew that the ~ost sevare flood.produci~9 storms h~ve occ~~red
<br />J'~rcng the late spring or .urrrwr Clonth.. ~,uch of the total pr~cip-
<br />i tatioo i1t :ha ~,igher elevilUons is in the form of .noLli. ,,~noff
<br />fro~ this .no~ of:en augmented by gener~l preci,itation, is ~~ a
<br />
<br />rnaxt~,,,m " ce, late spring "'" aer:'y 8u~mer months. " the ~lainC
<br />~"gion, ",oat 0' ce, prl1cipihtion ;, ;, ce, form " rainfall '~hich
<br />occuu d~ring ',ialont th"nd~rstarma " irregulilr intsJ;vah. These
<br />ator". and ce, physical features 0' ce, watershed '"' produce ce,
<br />
<br />rapid co~c~nt~aticn of runoff thzt ~~arncterizac fl~sh floods of
<br />high peek f:oLlis, small volumes, and short durations.
<br />
<br />'Jebcitie.
<br />
<br />Along the ~itd Hora~-Dry ~r~ek study rsech, v~locitoes
<br />during the J~ne 191i flood avarag~d 11.B feet per se~ond (8.? mi:as
<br />par hour) according to tha USGS ili"~Br_Su~ply Pap..r 48?, "The Arkanse~
<br />Rive: Flood of Ju~e 3-5, 19n."
<br />
<br />r:oodRecords
<br />Thera a~~ no r~cords of s:reuIT st~go~ o~ di5ch3~ge"
<br />av~il"ble for '~ild Horse-Dry Cr"ok iIIhich derive hii'll geging
<br />st~tions maintained ~n the she..,,, ~kmnel. ~'ithout such date,
<br />~ha ::"t~ of rise ~n~ m.:riltion nf p~at floG'~u ~~".nct ~n occur~tely
<br />ddeJ;mined.
<br />
<br />~rkans~e Rivet or rount~in Cr~ak.
<br />
<br />1~rger espp.cts ~f flooding on th~
<br />Th~ flood brofiles e~d flocd&d
<br />
<br />fiooded Ar8~s. flood PJ;ofcl~s. 3nd C~oss Sections
<br />p:"tee 3 th~[}"gh 5 shc~ the "p~Toxi"."t~ 3re"s dong
<br />Wild Hcrs~_Ory CJ;eek that ~culd b~ inund8ted by the Stonda~d
<br />Projllct flood 'end the Intarm~diat" Region", Flaml. Th8 ~ctual
<br />llmi b of thnsa o'Je~flo~ ore~s on th~ g,'uund may vary slightly frr""
<br />tho"s sho~n on the "ap because the lO_faot oontour inoerv"i and
<br />sC31e cf the map do not pa~mit preaise piotting of the flooded
<br />~te" bound~rie~.
<br />Plataa 8 ~nd 9 show the high w"t~r profile~ fo~ the
<br />St~"d~rd Project "nJ ,nt.er'oedi<,te Regional rlatldc. AccurCltD e~-
<br />timatM of w~t..r aurf~ce elevaUonc may be otrtained fro", ths."
<br />
<br />i~ newspdp~r files ~nd other
<br />clusiv~ly concerned with tha
<br />
<br />Informution on past rlcods in the area. ~o aVClilable
<br />hls~orical documents, io almo~t ~-
<br />
<br />areas ~"po ~era developed fro~ the resulte of p~u'Jious studiu",
<br />field inveetiqations. and offi~e camputdtions.
<br />
<br />>,la~c::; .
<br />
<br />flood Occ,-,rr'mc"s
<br />Analysts of climatologicdl dat~ and revie~ of tha
<br />flnod h13tory far thO! Ark,,~s~" River ~LJbb'Bln ,~bov<l John ~1"rUn
<br />
<br />Plate 12 ~h()~'" two <:ro~s sedton~ that "". L~picd of
<br />th~ lC sectio~e obt"i~~d ~" ~ild Korse-Dry Craek in the "each
<br />i"vestig~t~d. The locations of ,,11 sections OrH ~hown on the
<br />"~<lV'-' r~f~~en",d phtes, '.}S ",~i; a~ th" ~l~v"t1ona anJ extent
<br /><of Dverf:,,~ or thB St"nd,,,d Project nooe ~nd lntor",~diilte P.~gi~~d
<br />
<br />Flood.
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