St. Louis Post-Dispatch 06/07/2011 Copyright © 2011 St. Louis Post-Dispatch $$edition June 7, 2011 10:03 pm / Powered by TECNAVIA Copy Reduced to 66% from original to fit letter page Flooding • An upstream dam failure along the Missouri River would wreak chaos, including in St. Louis. BYBERNARDSHANKS The reis ver y re althre ato a flood tha t wil l lea ve St.Louisin chest -highwater . Thereason:Six old, hug e, au ltydams thatnormallyhavereservespace o r spr ingsno w mel t arenea rlyullnow— be or e thespringfloods start . Flood gat es thathaven’ t been opene d in 50 yea rshave begunto open.Floodin g has be gun .And thehumanand economictollcoul d be ghastly. Whyanotherflood disas ter ? Six damsromFort Peckin Montana toGavinsPoint in South Dako ta, autho rizedby theFlood Contr ol Acto 1944, arein theprocesso ai lingat floodcontrol . Withspring wat er leve ls low , theycan holdback morethan thre e yea rso ave rage Misso uriRiverflow — enoug h tostop thewor stfloodsandprot ect750mileso theMis- sour i Riv er valle y andheartlandcities.Thisyear,that isnotthe cas e. Letme giv e youa senseo scale . Thesereser voir s aremassiv e.Fouro thenation’ s 10 larg estreservo irs arealong theMissouriRiver— Fo rt Peck,For t Ran- dall,Garriso n andOahe.Three o thesehad lessthan fiveeeto tot al sto rag e spacebehindthe floodg atesat theendo May .Witha combin edheigh t o700eet, thes e thre e damsare nearl y ull.Meltingsnowsurely willcomplet e thetask. WithcitiesromWolPoint,Mont.,to St.Louis aci ng rec ordlevelso wat er,hundr edso thous ands opeople arethreat enedby theunpreced ente d open- ingo floodg ates . Thegreate stear is themassiveFor t PeckDam,a hyd rau lic-filldam thatis thelargesto itskind. TheFo rtPeckDamis bui ltwitha flaw eddesi gn thathas sufer ed a well- knownateor thistype o dam— lique action— in whic h saturatedsoillosesits stab ility . Hyd raul ic-filldams areproneto almos t in- stan t collap serom stre ssor earth quak es.Calior nia requ iredall hyd raul ic-filldams be tornout or rebu ilt — andno oth erlarg e dams hav e bee n bui ltthisway since. Atthreemiles wide,For t PeckDam lastopenedits floo dg at es36 ye arsago .By theendo thefirs t we ek inJune , theU.S .ArmyCorp s oEngin eer s will be rele asinga reco rdspill o wat er. Thecorps rece ntly answ eredthe quest iono poss ibleailurewitha stat ementthe damis “abso lute ly sae . ” It maybe the larg estat-risk damin thenation. Downstre am,GarrisonDam neve r hashad touse itsfloodga tessince thedam wasconstruc ted50 yea rs ago . Bymid-June,the corps plansto dumpwater equalto a good -size d riv er . Thesame is trueor Oahe Dam,the nextone downs trea m.Since thereserv oirs arenearlyull, thecorpshas no choice. Efec tivefloodcontrolromsixlargedams is no long er an optio n. Asa corp s repr esent ativ e said , “It nowmovesus into uncharted territory . ” We mustall posea quest iono nation al signi fi- can ceto thecorp s:Whati F ortPeckDamshou ld ail? Her e is a likel y scena rio:Garrison , Oaheand thre e otherdownst rea m earth en damswouldhave tocatch andhold a massi veamount o wat er , an areacove ring near ly 250 squar e miles100 eetdeep.But earth en dams , whenovert oppedwithfloodwat er , do not stan d.They brea k anderode awa y,usuall y withi n an hour . All areull. Ther e is a poss ibili ty a ailu reo Fo rt PeckDam couldleadto a domi no-lik e collap seo all fivedown- stre amdams . It prob ablywouldwreck eve ry bridg e, high way , pipel ineand power lineand splitthe heart - lan d othe nat ion ,leavi nga gap 1,5 00mileswide . Coun tlesssewag e trea tmentplants,toxi c wast e sit es andeven Super undsiteswouldbe flushe d down- stre am.The deathtolland blowto oureconomy wou ld be ghast ly . Y ear s ate r Katrin a andthe NewOrlean s leve e bre aks,pro essio nal engine ersand a ede ralcourt judg e ruledtheCorp s o Engine erswas toblame. Ar e weonceaga inat thebrin k oa mas siv e corps ail ure?The corp s is ina mousor manag ementer- ror s,cavingto commerci al pres sure andlosing sight oits prima ry mission.This pendi ng thre at isso hug e thatit is gamb lingwith thenation’ s secur ity . Thecorp s isplaci ngthe nat ionat ris k,andi the damsail,Leon Panett a, whowill becom e secr etar y o De enselater thismonth,will havethe gre at Miss ouri FloodDisast er on hisdesk. Andthe entir e nationwill deman d answersas towhy theU.S.Army Corps o Engin eersdid notavertdisasterwithmore econo mi- callyand ecolo gical ly soundmethod s o floodpre- vention. Bernard Shanks, an adviser to the Resource Renewal Institute, has studied the six main-stem Missouri River dams for more than four decades. He has worked for the U.S. Geological Survey and served as director of the Washington Department of Fish and Wildlife. He has written three books on public land policy and is completing a book on the hazards of the Missouri River dams. The loomin g dam failure of 2011 MONTA NA OFFICE OF TOURISM TheFortPeck Damin Montan a. Withunprec eden tedfloodingin theupperMidwestthis spri ng, some peop le are conc erned abou t thedam’sstabilit y. LARRY MAYE R • AP TheMussels hellRiverfloodshomesand farms near Mart insd ale,Mont.,late lastmonth.
