FLOOD04939 - Laserfiche WebLink

Home Browse Search

HlO FLOODS OF 19G;) 1::\ THE U~ITED STATES sorTH PLATTE IUYER BASI);"~ COLORADO) .TFNF; J 965 Bll up Ia.rge allu\-ial fans at their mouths. ~rany old l:.:OUollwoocl tre('~ along Plum Creek were uprooted, splintered, and pe('lec1. Throug-h DeIlYf'l' and its ~lIl)lll'h:=;~ the urn.ount of oyC'rbank flow along tlw South Plattf" Hin~r \\'as :1fgT:1yated by plugged bridge:.;: and tlip dqlth \\":1:' illCr\::1.':-t'd hy t..'nn'O:1<:,h1!l('!lt:-- Oil the Hood pbil:. En']1 ""itlt. out these complication..-, rl\(> ill1mdatioll \\'o1l1d lw\"(' b('('1t tilt' .:.!TC':lt(l.'--t since at least ltl"!-k Along BijOH Crppk and if:..; tributarip.-:~ :'-:Ollh' matlll'(' alLtli'<1 CI'op~ were almost C'omph,tC'ly !J\!!'ipd by s('climellt~ Ill;\l1y trl'C':-:; \\"t't'c uprooted. and channels were widened by bank cll.tting. _\t on" location on \V(':,t Bijou Creek north of Byers~ prefloocl ,-egetation was found under 1:2 feet of 11m,,']y deposited sHliment (~fcI\::ee and others, liH:;7, p. 638). The main line of the Chicago, Burlington & (~nincy Hailroad, built in 18S2~ crosses Bijon Crrrk Ilear 1Viggins, Bijou Creek floods haye causf:cl m.inor c1amag-e to the railroad at times and major damage in 1935~ but nothing n:::C'mbEnf!" the damage riluSrct by the floods of .runt.' W65. The foregoing- example5 arc onlY;l few of the major changes made in channels in the flood area. )'Iost of the ehanges were grt',-lter than auy experienced at ]easl since the area ,yas spttIed, and the.y occurred in a sort time internll------only a few hours at the nlost, Such changes are in-efuLahie e\-idcnce that a fiood of great 111agnitude occurrect, CAUSES FIGna; .l.-Ht':,ulb of on.rl:l1ld flow ,i1(ln~ Ell:,t I'lulII ('l"(>('k south of Ca:-;tle Ho('k. Colo. I'hot(J~r:lph h,\' ('0101":1(10 .\rIllY :\:10011:11 (;l1ard on ,Tttnp 18. Ifl6:i_ The floods in the South Platte Hi"er basin were not caused by one m'ent, as often happens, but by sc,'pral storm cells in three main areas on three different days. The area north of the. South Platte Hi,-er betwe('n G-reelev and Strrling recei,-ed heay\". intense. rains durin!! the nl!!'ht of .1"l1ne ]-!-J;"i, ~ . .- Torrential rains fell during- the afternoon of .Tun(> If> near C'a::::tle Hock and Larkspur, :30 miles south of Denver. Scn're I hundprstorms oc- curred on .Tune J;; in the Bijou Creek basin southwest of Deer Trail and again Oil tlH' aftprllnon and c\'enin(r of .Julie 17 aloBIT the hcad- water~ofHij()l1 ilnd J\iowa Creeks, ~ e- III Jif!t1l'c-t. tIlt' :-iolid lille;-: arl' triIJlltariC':-5 of East. Plum Creek as tlwy an' depiell'd ill aerial photof!raph:-; tnkt'll ill Ol'toht.'r 1964, The da~hed lines arc the limits of the lllP;ln<!er:-; of tIlt' lo\\"~\\"ater channel amI of (l'eC5 and In"ush of lIloderatp dpllsity. Til(, light art'as ill the photog-raph arc depo:;its of :,edill1l'ut. Xotl' the two Illajor ('hang-es in tht' lIlain ('hallllcl position and that Il\O~t of the trees and brush haye been washed out. A short reach of East Plnm Creek ,It Castle Hock had beei1 relocated twice during- l'pcpnt hig-hway ('()n~truction, During the flood rln' flow ~llllght tIlt. original ('Ollrsp of Ill(' ~rn'nlll all(l sen>l'c-ly ('ut lloth Illl' liP\\" alld 01(1 bank:" St.'n"rul ea;.;tprn tl'lbntal'leS of ""est' Phllll ("n'ek built .\XTECEDEXT COXDITIOXS Hain:; had been fairly general and frequellt oyer the South Platte Ri\'er basin since :\Iny ~1. Daily rainfalls of o,'er 1 inch "-ere recorded at sereral sites between 11a)" 21 and .Tune .3. Storm acth'ity increased on .June -1 and 5 with many reports of 2 to :1 inchps of nrpf'loitMlnn during these 2 dass, Light-rail~ o('('UlTE"(l at lllany place; mos~ ()f-til~ days from June 6 to.June 1:,.