<br />DIBUS non ftOH ftIBUTAlIIS or TIll COLOlW)C) 1UVD.,
<br />ClAD CANYOI RATIOIULPAU, AlUZORA
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<br />Robert H. Webb, Patrick T. PrinSle, and Glen R. Rink
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<br />A reconnaissance of 36 tributaries of the Colorado River
<br />indicates that debris flows are a ujor, process bywhiehsediment is
<br />transported to the Colorado River in Grand Canyon National Park. Debris
<br />flows are slurrie. of sed1Jlent and water that have a water content of less
<br />than about 40 percent byvoluae.Debrh flows occur frequently Inarid and
<br />sea1arid regions. Slop. failures cOllllllonlytriggerdebrisflows ,which can
<br />originate frOllany rock formation In the Grand Canyon.. Tltelargest and
<br />lIO.t ,frequent 'now. originate ,frollth.'PemianHemi t Shale, ..,', the 'underlying
<br />IIIplan&de Sands ton. of the iSup.i Group , and other formations of the Permian
<br />and PennsylvanianSup.iGroup.Debris flows also occur in the Cambrian
<br />HuavL1lleston. andunderlYing~rightAngelShale and the Quaternary ,basalts
<br />in the~stern Grand Canyon~." .
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<br />Debri.-now fr.quencY,andllagn1tudewer. studied in detail in
<br />the Lava-Chua.!"Creek.drainag.>at.ColoradoRiver IIi Ie 65~5:inth. HOllUllent
<br />Cr..kdrainage.t II1le93~5;andinth. Crystal Cr..k drainag..tllile
<br />98.2. Debri.nowshav.r.ach.dth.Colorado "Riv.r,onanav.rag.,ofonce
<br />.v.ry ,20 to',.' 30 , y.ars ""in ",the'dI.av..Chuar:cr..k;'clr.inage ",' sinc.,about',l916.,'Two
<br />debrisf1ov. :have r.ached ." the'ColorAdo River ','in' ,.,,' the ' l...t: 25 ',. .years.\in
<br />Komment: Cr..k. Th. ,CrystalCr..kdrairi&g. hu had an <averag. of one
<br />debrl.now reachlngthe'Colorado'(ll1v.r.very50ye.r. ' although. the .
<br />debrl. , flow" of 1966 baa, 'be.n the.onlt now that r.ach.d' the ,Color.doRiv.r
<br />sll1C. 1900. , Debr.1sflon.,.,~:~yactually,r..ch th.Colorado Rlver""lIOr.
<br />fr.quently,.,,'ll1.th.... dr.l~I..b.c:.U8. "'".videnc. 'foralldebrl..' now...ynot
<br />',' have" be.n.pr...rv.d ''In. the'c:hanMl-urgln.y.tr.tigraphy. ",'
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<br />ABSTRACT
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<br />J)f..charl...).',."..r.".,."..II~.(~t;d..;.tor' '.th~.'peak.,. flov,.of,',.thr..debrh
<br />flow. ,thatr.ach.CS<th. " Colo.r~ I.iver.Tb..debrl. flov,of'1966,,'inth.
<br />Lav.-Chuar" '.' Cr..k.idr.f.llas.)had~an?.tillat.d.eli~charg.of4,~-.,~ublC~f..t
<br />per,'.....cODd. ,,"'., Tb.....debri..nOW,~f....,l984f.ft'~tM..HOiiUIIentCr..k - drainag.;:...'"'had.,,. ",'a
<br />eli.charS.' >..tillate~b~tve.n.3~j600,and,4. 200 cubicf..t, p.r..colld.'Th.
<br />debru flow' of.1966'1D.the'~ryllt&liCr..~:.dr.lnas.. hadadl.cbarS....t1llat.d.
<br />betwMD ",.9 ,200'ad "14'OOO'rcUbic'.,f..t"per...cotacl~<Deterainatlonof the
<br />....ffec.U'Y8 .cro..,:",..C~~cmal~.r~:","'.i.probl_"lD....ll'c.lcu1.ti~ ',.,."in'90lv11l1 .
<br />"supU.lmttoa.'.OIl;~;beC....~;.t.I'."':MU ..r.lev.tlon....rlcs.ver.l.5.
<br />'.,to.,..3~~;.t1lle. '1Us.r.;:~i';ar.~1;10.f.,...tr.~'or... 'cS0vn8tr...cro....ct~01l8..
<br />. 'i' ','" ',',.. .,.:.," ,'.'" ..,..',..:.;..."j,i,. " ,""..', '",'.,'.....,..,,".,';...'..:.;.~...ii.. '.',',..",,'. ..,..' "'..,..,'...,.'..."".'.,' '..,'.,'.." ,', ,,:"',.: ';,/'
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<br />.' . ,Co .' Deln:1.;,f1oniJi:the,Cracl;;c..,.ous.nerallYar..cOilpO..cl:oflOto
<br />40 "parent; ~.ad..,',~.'!~"1&ht'.',,&Dd .,..,..repl'....8Ilt...,...lPiflc&1lt;,.ou.rC.Of,. ,,',' .'beach-
<br />.bu11dla1\~,~~<&1.OaI..C:hj,... COlorado,atver,...".,...Tbe' partlcl...al...d1suibutiou
<br />' ~..~'fOftl'(8orted;....the1arp.ttr&UfOrtedibou1del'.'..re i,' 11l .the
<br />.C1:yftal.> C:l'eek.1:;;4J..1"~luae~,t 'l'tie.;lU'pb,Ould:el'... trwperted1'ntO . the ',., Colorado
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