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lO-High Country News-Dec. 12, ,1983

Une R.'-renc.e Target L

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byT.]. Wolf

As a Bureau brat growing upiri Denver in the 1950s, myfavorite critter was thebeaver, my contributions

to 'show and tell' at school wereBureau scale models of dams, and myidea of a vacation was a family trip outinto the desert where I could see the.river kicked in the teeth by one oranother dam. I knew about ChuckYeager and the other heroes of TheRight Stuff. But my heroes weren'tflyboys or cowboys. They wereengmeers.That was only narural since my

father was the Bureau engineer (in myworld, there was only one 'Bureau')who designed the powerplanr at GlenCanyon Dam on the Colorado River. Itwas also natural that I would grow upthinking Glen Canyon Dam was athing of beauty and a joy forever."Just think of it from an'

engineer's point of view!" my fatherwould say, Six ..hundred feet of acurelyangled, dazzling white concrete wallsarching up from the frothy white anddeep green Colorado running in its redsandstone bedrock, up into thecloudless blue sky thar caps thedesert.Wha r a dam! What a site for a

dam! With its crest at an elevation of3,715 feer above sea level, the dambacks up the river to create amarvelous hydropower head. Fromthat man-made height the waterzooms down stainless steel' rubes todrive $200 million worth of turbines '--enormous, delicately balanced tur-bines housed in the powerplantnestled in the shelter of the dam'sarch.Smoothly spinning turbines, pol-

lution-free power, a blooming desert,What more could anyone want? And rocap it off,. as if to defy the SierraClub's sensitivities, my father and hisfriends threw in a surrealistic twist.Between the base of the dam and thepowerplant there is a fertile crescent --a flat, football-field-sized area sownwith rhe finest Kentucky bluegrass,thriving on cold Colorado River water,

. and carefully tended by Bureaupersonnel. It's the meticulous touch ofthe engineer. The sign that every·thing, but everything, has beenthought of and is under control.The symbolism of that grassy field

was put to hard 'use this summer. Fora time, there was a man 'haying thatpeculiar meadow all day, every day. Itwas a war- time routine calculated tokeep everyone calm; to show thateverything was under control.

The Bureau showed' the Right Stuff,

How LakePowell

of ,Glen Canyon Dam

But above that calm andscripted scene, above thepurr-putt of the two-cycle

Briggs and Stratton lawnmowerengine I Glen Canyon Dam was introuble. Glen Canyon Dam wasshaking, vibrating madly. Tremen-dous rumblings from the galleries --the hollow passages in the dam'sotherwise solid interior -- sent securityguards scurrying to close the top of thedam to visi tors,

The shuddering had its origin inGlen Canyon's spillways. Most damsspill their excess water over the top,over specially designed concretewaterfalls that present onlookers witha show when a reservoir fills andspills.Glen Canyon Dam is different. It

spills inside, down spillway runnelsthat take the water from upstream,pass it beneath the dam itself, anddischarge it downstream from 41-footdiameter spillway mouths.For two decades, those spillway

mouths gaped dry and empty, eversince Lake Powell had begun to fill.But on June 28; 1983, early in themorning, those spillway runnels were·at work .. work that was nor goingwell. You could hear loud, fearsomenoises in the left gallery within thedam and also on top, where the risingsun was warming the white concrete.

If you were on the bridge thatspans the canyon below the dam thatJune morning, perhaps enjoying thSspectacle of the water jetting white outof the spillway mouths, perhapsworrying about what the spillagewould do to your river-running friendsdownstream, you would have seen asight terrifying enough to.put the fearof God into anyone, but especially into_an engineer.

You would have seen the steadysweep of the spillway mouthssuddenly waver, choke, cough, andthen vomit forth half-digested gobbetsof steel reinforced concrete (bad, verybad), spew out blood-red water (MyGod, it's into bedrock), and finallydisgorge great red chunks' ofsandstone into rhesfrorhy chaos belowthe dam.

You would have seen the ColoradoRiver going home, carving rock,moving deeper, as it has always done.

Ifwe can say a river is wrathful,then we can say Glen CanyonDam was the object of the

Colorado River's wrath last summer,when flow into the Colorado Riverbasin grew from the normal 6.96

million acre-feet to 14.6 millionacre-feet during the April to Julyrunoff.

That doubling threatened to spellnot just the end of the dam, but alsothe end of hundreds of professionalcareers. The engineers who designedIdaho's infamous, failed Teton Damwere forced into retirement becausethe dam's failure was actually theirfailure. Some of them died soon after.

But if the Bureau lost GlenCanyon, it would be more than a dozenor so engineers forced out in disgrace.It might be the end of the agency. The

~ flooding Coiorado was posing thesame question to the Bureauengineers that space ·posed to thosewho woold navigate it. .Did theydesign their technology correctly?Assuming their design is right, dothey have the skills, the knowledge,

the coolness, and the guts to operate itunder extreme conditions? Do theypave the right sruff?It can be argued that more than a

dam, a federal bureau or professionalcareers were at stake. The Bureau ofReclamation stands for an approach tonature that says rivers, forests,resources of all kinds are there to bechanged, transformed and reworked,until they respond to flicks ofswitches, until they go on and .off atwill, until they produce exactly whatman wants.

Glen Canyon Dam provides a clearexample .of this dominance overnature. Glen Canyon and Hoover arewhere the undisciplined "useless"rushing of the river is turned intoelectricity -- a form of energy that -cando all the things engineers wantenergy to do ..

The Bureau's approach torivers is

flashboard

A photo -ofone of the radialgates is atupper...right. The upper left 'box shows agate in the shut position. Note the s.foot-steel flashboards above the gate. The

dam

3176

3135 '.

crosssection in ~hemaindiagramshows 'agate partially open. It also shows wherethe old, plugged diversion funnel meetsthe spillway. The numbers arefeet abovesea level.

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Dec. 12, 1983--High Country News-ll

almost broke freethis summer

as opposite as can be -to that of theriver runner or kayaker. IThose whoride rivers, who go with the flow, wantto master a river without breaking it.They want to experience the river.without putting their mark on it. Theriver people, and those who sharetheir world view, had as large a stakein the drama that played out thissummer in Glen Canyon Dam as theBureau did.

At stake was the way our societylooks at nature. If that had beenknown, all sorts of people would havebeen standing on the bridge below thedam ., a bridge that provides awonderful view of the dam and itsspillway mouths, the grassy crescent,and the powerhouse. It would havebeen a great place for -the riverrunners to stand and cheer on theriver. And [usr as great a place forthose who feel they and society lost atThree Mile Island at Teton Dam tostand and cheer for the Buteau toshow it has the right stuff.

Ifyou had stood with me and myfather on that same bridge atits dedication in 1959, you

would have been peering down intothe narrow: canyon as he explainedwhy the river disappeared from viewfor a stretch. You would have heardhim say that the Bureau engineers hadrouted the river in a runnel around andunder the damsitc so that they couldpour concrete for the dam'sfoundations.

Carefully boring through the softred sandstone that must do here fatbedrock, Bureau engineers haddesigned two concrete- lined diversiontunnels that led through the canyonwalls, around the places where thedam would be married to the canyonwalls (the abutments), and down intothe canyon below, where the runnelsspilled the Colorado back into itsaccustomed bed.

If you had returned with us fouryears later, in 1963, to witness LadyBird Johnson dedicate the completeddam, you would have seen a differentsight. The diversion tunnels wereplugged now, and the dam hadalready trapped enough of theColorado's flow to create an infantLake Powell -- small, but showingsigns that over the next two decades itwas going to become a very largereservoir indeed.

This time, you would have heardmy father explain how the engineershad not wasted the diversion tunnels.They had poured concrete plugs into

the upper section' of those tunnels,cutting them off from the river.

But then they had made the. downstream sections of the two.diversion runnels part of the newspillway system. They had built newtunnels down from above. They hadmarried the downstream part. of thediversion tunnel to these new slantingconcrete tubes coming down fromabove I with the' connection pointupstream of the dam, right below theconcrete plugs.

Those new slanting spillwaytunnels rise at a 55 degree angle fromtheir merger with the old diversiontunnels at the bottom of the reservoir.Then they open out into the reservoir,600 feet-upstream from the face. of thedam, up against the.canyon walls oneach side. Water gets to the41-foot-wide tunnel intakes by flowingthrough concrete approach-channels.The lips of the spillway tunnels are

at an elevation of 3,648 feet above sealevel. But even when Lake Powellreaches that height, the spillwaysdon't necessarily take on water. Theyare each guarded by two curved radialgates, 52.5feet high. Those gates areraised and lowered by boomsanchored into the canyon walls. Whenthe gates are down, the water levelmust rise another 52.5 feet before itcan flow over the gates and get to thespillway. That means Lake Powell can

rise to 3,700.5 feet before it can spill.If water flows into the reservoir fasterthan the spillways can take it away,and the reservoir continues to rise, theultimate spillway is the dam itself,which is at 3,715 feet of elevation ... The Bureau engineers are sure thedam can spill without suffering anydamage. But the $200 millionpowerhouse and turbines at its base,to say nothing of the fertile greencrescent, would be washed away like a .log.In addition to. the tunnel spillways, .

the darn has twO other ways to releasewater. One is through the river outletworks (ROW, if you like acronyms) --four steel conduits, each eight feet indiameter and controlled by hugevalves.The third way is the only one the

engineers ever want to use -- throughthe steel tubes that lead to theturbines themselves. For water thatgoes through the spillway tunnels orthe river outlet works does notgenerate electricity. The Bureautries to only use the power plant, sothat every drop of water produces a bitof electricity. _.

This summer, as everyoneknows, the Bureau had towaste water. It had to send

water through _the tunnel spillwaysand the river outlet works .- water that

didn't produce a watt of energy. Innormal times, that would have. been ascandal. "But this""summer, waste wasthe least of the Bureau's worries.

The real worry. was that, becajsseof this peculiar design, the ColoradoRiver came close to beating theBureau, close to showing that it and itspeople didn't have the right stuff, by-getting in at the grouqd floor andblowing out the dam's soft sandstonefoundations.

The underground spillways camedose to providing a route for thereservoir to rush under the dam anddown the river, to overwhelm HooverDam, and to continue the process,toppling the other dominoes in thesystem -- t~e dams at Davis, Parker,Headgare Rock, Palo Verde, Imperial,Laguna, and Moreles, each of whichwas already dealing with desperateconditions. Suddenly, the Salton Seain extreme southern California couldbe some fifty million acre-feet bigger.Or the Colorado River might find anew outlet, a new way to the sea. Anver once more. ,;::

Ironically, the ck." Glen Canyoncould have caused might have sparedthe visible part of the dam itself. Theriver might have carved itself a newpath downstream by ripping open thediversion tunnels, but the dam might

[Continued on page 12)

A view from above. Note especially that the rig'ht from the left. Roclf. walls back the-tllnnel mouths on the(lowe,r)lspiltway tunnel passes beneath the 'dam . Note three other side. The radial gates guard them from thealso that water can flow into the spillway tunnels only front (left).

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12-HighCountry Neu/s-Dec. 12, 19?3

GlenCanyon .•.(Con'inu~d from page 1Jj

have stood, whatever was gomg onbeneath it.Certainly, it would stand if water

spilled over it, or piled up behind ir ineven greater quantities than it did thissummer. Glen Canyon is a toughstructure, a gravity dam that is alsocurved. Most gravity dams, such asthe Grand Coulee on rhe Columbia, arestraight and set at right angles acrossthe river.The straight dam depends on irs

weight to keep it from slidingdownstream. It sets there, squat andponderous, pushing back against thewater behind it. But Glen Canyon iscurved like an eggshell, wirh rheconvex parr of the eggshell pointingupstream. The result is that· thedownstream force of the water is'transmitted along the eggshell to theplaces where the dam aburs thecanyon walls. Instead of resisting thewater's force by its own brute force, itenlists the rock of the canyon to holdback the water.

So rhe dam isn't simply a heavyirrigation rock set into the-canyon. It ismore like a barhrub plug: the harderthe water pushes on it, the more itpushes back.And in a sense .. a sense the river

runners might appreciate .- the GlenCanyon Dam is made to go with theflow. Ir is built of enormous concreteblocks thar are designed to shift, tosettle, to drop into openings, shouldthey appear, as the pressure on thedam face shifts or changes.

As we said, this summer,because of the dam' 5design, the Colorado River

came close [Q beating the Bureau. Thedefense against such a technologicaldisaster,. or victory for the river,whichever you choose, was the liningof the spillway runnels -- a barrier ofconcrete reinforced with heavy steelbars. Alrhough the steel rubes of theriver outlet works and of the powergenerating system were designed totake the beating of tons of waterfalling at 120 miles per hour, theconcrete spillways were never meantto withstand such conditions.When water rushes over concrete,

no matter how smooth the concrete, itwill erode. The erosion can cascadeand multiply when grains dug ourupstream become grinding, tearingagents downstream, ripping out everlarger chunks under the double pushof air pressure and water pressure.

And beyond the man-madeconcrete tunnels was something worse-- soft Jurassic Navajo sandstone.composed of quartz grains and a lirtlefeldspar. Ir is borh moderately porousand highly absorptive. Nor the bestbedrock to hold back millions of tons ofwater, as the Colorado has beenproving by vrnillenia of downcurting .But Glen Canyon was the best physical.site fOf a dam .. a site so narrow andwirh . walls so high thar Bureauengineers had to put their spillwaysthrough the rock because there was noroom for them elsewhere.Spillway damage is norhing new. Ir

.eveD has a special name .. cavitation.Hoover Darn's- own tunnel spillwayshad experienced ir in 1941 aridMonrana's Yellowtail Dam hadexperienced a 1967 episode whichprovided rhe dara for designs tocorrect the potential problem ar GlenCanyon. The correction was airslotsbuilr into the tunnel walls to bleed offrhe air trapped with rhe water andreduce pressure.

Adding its overflow to Glen Canyon Damwas the Morrow Point -Dam: 468 feelhigh and the Bureau of Reclamation's

Cavitation is Bruce Moyes' special-tty. An engineer at the Bureau'sEngineering and Research Center inDenver, he headed the special teamassigned to moniror and manage GlenCanyon Dam last summer. His jobnow is to make-engineering sense outof last summer's near-disaster and topropose design solutions that can beput into concrete before next springbrings an equally high runoff.Working in a building at the

Denver Federal Center so functionallyugly it has to have been designed byengineers, Bruce cultivates a beard, asense of humor, and a respect for thepower of the Colorado River.

W~en you call Bruce's office, avoice answers, "Concrete Dams!" in a[Onereminiscent of one of my father's"favorite sayings: "I like people andtechnical problems, not necessarily inthat order. " 'In addition to his cavitation work,

Bruce has a long-term assignment. Hekeeps track of the evolution, theaging, of Glen Canyon Dam, which hetalks about as if it were a living thing,a moody critter that moves andchanges, keeping time with the movesand moods of the Colorado.

In the course of the day 1 spentwith Bruce, I related to him some ofthe charges made by Bureau criticsconcerning last summer's recordspills. He replied, "Hell, we couldhave just run 100,000 cubic feet persecond down the Grand Canyon

first thin--arch double-curvature dam. OnJune 29, 1983, Tom Fridmonn took thispicture dxring "one of the rare moments

duringJune and flushed everyone andeverything out. That would havesolved our technical problems andsaved the dams too.

"But our goal was to save thedams and the people downstream inthe floodplains. Not easy. But webelieve we succeeded as far aspossible under the circumstances."

What were those 'circumstances?'According to Bruce it' was an evermounting flow of water into LakePowell that required the Bureau tobalance. off imponderables. Thechronology that follows draws on hisaccount of the summer and on Bureaudocuments.

June 2, 1983. This day can betaken as the start of the crisis. Thelevel of Lake Powell exceeds 3,696 feetabove sea level and Bureau officialsdecide that powerplanr dischargesalone can . no longer control thereservoir rise. They raise the leftspillway gates and dump an additional10,000 cubic feet per second (cfs).Over the weekend, they increase thespill to 20;000 cfs,Jun~ '1J'ain personnel hear

rumbling noises and see materialshooting out of the left spillwaymou th. Engineers fly out fromDenver. But before they arrive, thedam manager has shut down the leftrunnel and opened both .rhe rightspillway gates and the river outletworks. The Deriver team ·boards acontraption called the cart, which is

when the dam spills because ofhigh. water flows."

lowered over the left radial gates anddown into the intake. They observesome cavitation damage close to thepoint where the tunnel from abovejoins the horizontal diversion tunnel --right at the elbow.

That leaves them with nastychoices. If they reduce flow rhroughthe left spillway tunnel, the reservoirwill continue to rise. If it rises until itovertops the closed gare, it might jamthe gate shut and water will spilluncontrollably over the gate into therunnel. If there is too much water evenfor the spillway tunnel, the reservoirwill continue to rise and might overtopthe dam, washing our the powerplantat its base.

To the engineers on the scene, themaximum reservoir height seems tobe 3,700 feet -- the top of the radialgates. But higher authorities in theBureau overrule them just as the riveris overruling the dam. Under orders,the engineers arrange for theinstallation of four-foot-high sheets ofplywood, called flashboards, onto thetops of the radial gates. In effect,the radial gates are now 56.5 feet'high, and the reservoir can nseanother {our feet without flowing overthe gates and into the spi1lwayrunnels. It buys time by creating asurcharge pool in Lake Powell.

Along wirh the flashboard installa--tion order comes disturbing news fromrhe National Weather Service: inflowfore cas rs for Lake Powel1 are

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Dec. 12, I983--High Country News-I3

GlenCanyon...(Continued from page 12)

accelerating. Other disturbing newscomes from closer by. The teamdescends into the 'dam itself, into itshollow insides, the galleries, on thetrail of the rumbling noises heardearlier. Since the left tunnel istemporarily down, the noise hasceased. .Bur it doesn't 'take- a 'closeinspection pf the watery confusion in -the galleries to shew-that _the river'outlet-works coupling's are leaking,and that manhole covers throughoutdie darn show increasing signs. ofpressurization. Everywhere, like corksin _shaken champagne bottles, varioussystems are responding' to increasingpressure from the rising wall-of waterbehind' the dam and the huge flowsthrough tile dam.

Meanwhile, on the ..225-mili:stretch of the Colorado that windsfrom Glen Canyon downstream toLake Mead, Park Service helicoptersdrop the news, about the increasingreleases to .river runners: "CampHigh! Be cautious!" .

The Bureau was takirig its-ownadvice. on 'caution' as this reportsummarizing the early summer appre-hensions shows: "The intial concernupon the June 6 report was noisesfrom the left tunnel was for the safetyof the dam and its foundation. Thisconcern predominated throughout thespill' period."June 7. The team brings the

powerplantflows up to 28,000 cfs -- 20percent over normal capacity. Theyhold the river outlet works to 15,000cfs. That keeps water speed down toonly ~Omiles per hour. And they holdthe right spillway to 4000 cfs. Theywant to keep it low because it occupiesa, d9:ng,erQu~_.,P.'~i¥,g~~~tf~am f~OIll.Ithe dam's foufldal10n. If the rightspillway tunnel broke through tobedsock, it would threaten the dam'sfoundation.

They also get organized. They setup twice daily inspections of bothspillway portals, of dam abutmentleakage (warer flowing through jointswhere the dam meets 'the canyon), anda more technical evaluation of damnoises They' have been using:"Scares rhe hell out of me!" forserious sounds. From Bruce Moyes'account, you imagine the teammembers like men 10 battle,experiencing feelings of elation andcamaraderie alternating with convic-tions of isolation and doom. Noah andJonah jokes abound.June 8. The-left radial gates are

fitted with their flashboards. Attentionrums to the right' radial gates.

Hydraulic computations give addi-tional reasons to baby the right. spillway. So long as 'the water erodesstraight down, everything is safe. Butdamage patterns, the computationsshow, also like to spread out laterally,or horizonally. Since the right tunnelelbow is near the' dam, horizontaldamage spreading .. out from thetunnels could threaten it.

A related worry is that damage tothe concrete plug in the right tunnelcould create a direct connectionbem,een Lake Powell and the river viathe old diversion monel.

June 9. Total discharge is at 48,000cfs and the National Weather Servicerevises irs predictions upward. Theteam decides that the river· outlet-works couplings are going to hold.June 10-II. The right spillway

radial gates have . their flash boards .Total discharge'is held at 48,000 cfs.June 11-12, The river outlet works

are discharging 17,000 cfs with noproblem. But the reservoir continuesto rise.june 13. The National Weather

Service ups its predictions by 500,000_acre-feet and the team thinks that itsforecasts will always err on the lowside. They also realize that theycan't

/ totally shut down the spillway tunnelsby lowering the radial gates. Thatwould put toO' much pressure -on thejury-rigged plywood flashboards atopthe gates. But Bruce Moyes says therewas 'one comfort:

"The inherent stabiliry of the damand its abiliry to bridge 'openings inthe foundation gave us confidence thatno sudden" loss of reservoir waspossible. But arw direct connection (ofthe reservoir through the spillwaytunnels to the river downstream) couldlead to erosion of the sandstone andthe potential for -uncontrolled releaseinto Lake Mead was a real concern."In other words, the dam could hold but·.rbe rimnels could give way.june 15. Discharge is up to 53 ,pOO

cfs, but the reservoir is still rising sixinches a day, Babying the crucial righttunnel, the team increases the leftrunnel by 7000 cfs, upto 12,000 cfs,and the reservoir as a whole up to60,000 cfs.june I6.-Someone figures that only

200 feet of soft Jurass!c sandstoneseparate the spillway tunnels' fromthe dam abutments,june 17-21. Anticipating lawsuits

and Congressional investigations, theteam establishes a memo system todocument how decisions are beingreached. That system comes quicklyinto use when the left spillwaydischarge falters on June 18 anddisappears on June 19. "Ihey take achance and lift the left radial gatesfurther, hoping more water will blastout the obstruction. It works and thewater discharge downstream of thedam resumes.

- I... june-;: 2~2. Bureau GommissionerRobert Broadbent and all the .bigBureau chiefs, decide in Salt Lake Ciryto go from the present 61,000 efs up to70,000ds at Glen Canyon and to beginspilling at Hoover. The team is told:"We strongly recommend that

discharges from Glen Canyon pam beimmediately raised to 70,000 cfs toprotect the safety of the structure. It isimperative that discharges fromHoover Dam be raised to 40',000 cfs asoon as possible .. If the extremeforecas t of the NWS becomes-operational, the discharges from borhdams must be increased."The team, and the dam, is between

a rock and a hard .place. If theincreased flow of water begins todestroy the spillway tunnels, they willhave to shut the gates. Thai will knockdown the wooden flashboar..ds andcause a tremendous, uncontrolledsurge of water into." the alreadydamaged spillways, possibly destroy-ing them. "As if to underscore this concern,

the left tunnel's discharge fails again,even 'at 2i,oOO ofs,' which shouldsweep blockages away. And noiselevels in die dam and spillways arehigh. So the ream lowers -the leftspillway to 10,000 cfs ' and increasesthe right to 15,000 cfs. Noise drops'and the left discharge becomessmooth again. -

A June 23 memo answers thequestion: Would overtopping of theradial gates be serious.

'The answer must be a qualifiedyes ... expansion of the damaged areacould affect the stability of the canyonwalls. This is even more critical in theright tunnel since its elbow is furtherupstream" and therefore closer to thedam abutments.june 27. Heavy rains and high

temperatures in the, upper ColoradoRiver Basin force the te-am to go fromthe already high 70,000 cfs up to80,000 cfs. But raising the spillwaygates and actually getting the flow aretwo different things, The dischargefrom the left spillway is very weak.And there is booming and vibratingthroughout the galleries on the leftside of the dam.

~-\'"v ..Put' yourself in -the control-roomthat June 27 morning, when you feelfrantic about the left spillwaydischarge, and you are under orders toreduce the clam's noise and vibrationbefore the turbines start to wobble on --their axes and spin themselves into

destruction, just betore the spillwaysalso self-destruct.

You can't shut down the powersystem, and you dare not shut downthe river outlet works. So you turn thedials regulating the left spillway notdown, but up -- up from the 25,000 efsrate that is already performing atonsillectomy on the left spillway, upto 32,000 cfs. Your other hand revs theright spillway (the one you are reallyafraid to use) up, up from 10,000 to15 ,000 cfs. Counting everything, yourdials tell you the total discharge is92,000 cfs. What the discharge reallyis you have no idea. There are no flowgauges down in the bedrock.

While you play with the dials,maybe your inner video flips far up thechannel of the Colorado, far upriverwhere the waters of the apocalypsecreep towards Rainbow Bridge, someeight feet higher than the previousall-time high water mark. Maybe that-is where the environmentalists are onthis day of doom, saying: "We toldyou so!" Prophesying from RainbowBridge, crying forth in a loud voice tothe empty desert., to. the risingreservoir: ..Make straight the way ofthe Lord. Let the river flow."

Maybe such voices sou~ in yourmind back in the control room, as you. increase the flow in the righr spillwayup to 27,000 cfs, and wait. Then youhear it. Outside, the little two-cycleBriggs and Stratton lawnmowerengine labors on, shaving thebluegrass down to putting greenqualiry. Comforting, especially as you, realize you can hear it because theterrible thundering and vibrating hasstopped. For now.

Downstream from this suddenpeace,. the new Colorado has turneddeadly serious. Since normal flow is25,000 cfs, a release at 92,000 efsmoves like a tidal wave through theGrand Canyon. Pontoon rafts fortyfeet long capsize at Crystal Rapids,providing some passe ng'ers -wirheight-mile-long lifejacket ridesthrough seven other major rapidsbefore they reach shore.

Though helicopters evacuatearound 150 people from the Canyon,

(Continued on p age 14)

Hoover Dam's Nevada Spiilway ran atpeak capar::ityt'his summer, overflowr'ngat 13,941-r::ubr'r::feet per ser::ondand 4.5

feet above the spillway gates. What wasamazing, say Bureau' of Reclamationof/;"r::ials,is'that the sprtlway had been dry

every summer sinr::e 1941. This picturewas taken by IE. Kinsley 'on July 22,1983.

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GlenC.nyon...(Continued from page 13)

dozens are hurt and one drowns. Alsodsowned out and scoured away is thenew (since 1963)riparian habitat made possible by Glen Canyon's once steadyreleases. The Park Service is mad.-River runners are mad.

If the unregulated Colorado wassomeching that had to be controlIedwith dams, what do you calI this?June 29. Good news. Forecasts say

flow into Lake Powell is peaking. Sothe team drops the Glen Canyondischarge to 87,000 cfs.July 2. With both spillway tunnels

at 20,000 cfs, the right dischargefalters. It is upped to 24,000 cfs in anattempt to sweep it clean. Bur insidethe dam, in a gallery, drainholes beginto bubble violently. Great sighs of airand water surge from the drain holesin the gallery nearest the right tunnel.; the tunnel that comes closest to thedam's foundation. The team cuts theright spillway to 15,000 cfs. Thesurges calm, but no one knows whathas happened. Until the plywoodflashboards are replaced with eight.foor- high strong steel ones .. a job inprogress .. they don't dare shut theradial gates. And until they shut thegates, they can't go into the runnelsand inspecr the damage.July 4. Holiday visitors to the dam

can watch the construction companyworking around the clock to install rhesteel flashboards .. which will bestronger and four feet higher than rheplywood ones.July 6·7. Thesteel is in place and

the lefr runnel shut down. The team isswung into the tunnel over the radial-gates on the cart. There they find

much more damage than expected. Infact, the cart cannot proceed throughthe tangle of twisted steel andconcrete. The water stilI in the tunnelprevents an exact evaluation. But theyknow there's a: lot.

Most disturbing, they find damagemuch higher in the tunnel than expect-ed: This suggests that rockfalls haveoccurred in the tunnel due tohorizontal, or sideways, damagetowardthe dam.July 8. Today they ride the cart

into the now-closed right spillway.They find the damage on this sidestarts lower down than it did on theleft. So' they proceed down the'slanting elbow of the tunnel into thehorizontal section. There they attemptto launch a rubber boat over the smalllake filling an eroded portion of theconcrete. But they lose the boat tostrange currents and decide it makesmore sense to return to the surface.They have no desire to be swept out ofthe tunnel and into the river. Back atthe surface they open the radial gates,sending a modest 5000 cfs down eachspillway.

"Damage (to the left spillway) iu-dudes a massive hole into the sand-stone to about 36 feet below the tunnelinvert. The ups t r earn-downstrearnlength of this hole was about 150feet.It extended laterally (horizonally) toabout 15 feet beyond the full runnelwidth. "

In the-right spillway tunnel, a largehole extended ten feet horizonally be-yond the full runnel width, accordingto a report.July 15. The reservoir finally peaks

at 3708.4 .. some sixry feet above thespillway tunnel crest of 3648, and amere 7 feer below the crest of the damitself. Discharges ca'; now be droppedfrom 61,000 cfs to 51,000 cfs, wherethey remain.

July 23. With the reservoir at3707.8 feet above sea level, thespillway gates on both sides areslammed shut. The eight,foot.highsteel flashboards hold. It is 8 A.M.Crews prepare for immediate descentinto the spillway tunnels to beginplanning repairs.

Epilogue

When the spillway runnelswere finally completelydewarered in September,

inspectors found considerable darn-age.

I wish to thank Chief Engineer JimBrown of the Bureau for raking thetime to answer my questions and for

providing me with access to BillAnderson and Bruce Moyes. Thoughall of the Bureau publications and

.internal documents I have examinedfor this article are accessible to thepublic, I never would have been ableto sort out key materials without thehelp of Bureau personnel. I alone,however, am responsible for theinterpretation given them.

, ·0

T.J. Wolf is a freelance writerliving in Fort Collins, Colorado. Thisarticle was made possible by the HighCountry News Research Fund.

Copyright 1983 by T.J. Wolf andH,gh Country News.

Bureau downplays damage'The U.S. Buteau of Reclamation'

says it will cost $10 to $15 million torepair the two Glen Canyon Damspillways damaged last spring. TheBureau expects the repairs to becompleted by mid'; une, hopefully intime to handle peak spring runoffs.

The repaired spillways should bemore resistant to the 120 mile per hourflows. Air slots ate being installed toreduce the likelihood of damagecaused by cavitation. .

Most of the damage was sufferedby the left spillway. About 1000 cubicyards of debris .. concrete, steel andbedrock torn out of the spillways andrhe canyon walls .. will first have to beremoved ..Large amounts of water willalso have to be pumped out of theholes.

The Bureau estimates that 4000 to5000 cubic yards of concrete will beneeded just to fill the holes. An equalamount will be needed to repair thedamaged concrete lining. For compar-ison, a large construction truck can

carry about 10 cubic yards ofmaterial.

The work requites the boring of'runnels into the canyon walls to gainaccess to the horizontal section of thespillways. Th; left spillway repair is tobe completed by mid-April 1984 andthe less severely damaged rightspillway by mid-june 1984.

Clifford Barrett, the UpperColorado Regional Director, said thatthe extensive repair work necessary

I .didn't mean the dam had been inserious trouble.

"Despite the damage, which firsthad been observed early in June,neither the dam nor the spillways werein danger of failing. And while therewas serious damage to the spillwaylining. it was confined to a small areaand at no time would it have caused usto shut down the spillways. Consider-ing all rhe water that was spilled (4.4million acre- feet, including the bypasstubes), it was remarkable how well thespillways performed."

Ob! Weatherby (with apologies to Sir Walter Scott's Lochinvar)

, .;'>

To quote from HeN a verv short line.There are lands in Alaska less sullied, you, bet,That will gladly be home to this hiker and ferret.

So the hearing boss said yes, BLM unwound,And }'oung Weatherby took the podium with a

bound. ."..~ So stately his form, and so steady his pace,~ That never a heating such a gallant did grace.

The BLM fretted, the Forest Service scuffed,"The firms sat dangling all their permits and stuff.

For the public whispered, '<wouldbe a pity,Not to match our Wilderness to Young

Weatherby.'

And then it happened: HCN told the tale,The public read the facts, and did loudly wail;The permits were pulled, the agency caved in,Birds, deer, fish, people .. they all did win.

. There was noise from Carl Bagge of the giant coalclan,

AMAX and Amoco, they rode and they ran'.There was lobbying and suing thtoughout a1l the

land,But the vast Wilderness .. they had to unhand.Oh! Young Weatherby is come out of the West,The West is his passion} to save it his test.

Give a gift of HeN ... Let your friends and relatives followthe adventures of all the West's Weatherbys in 1984

Mail to: Box V, Paonia, CC5'81428-S~d---ifi~--d---h----b-;--------Tlse~~~-fi;~;'ft[;$I8J~;--~---rA~i~;~~~~~~on[;$J~70~------1en a gt t car. In t e name. eiour. I

I Name : Name IName I I I

I~ .- IAddress 1 : Cit" State, ZIP ,I City, State, ZiP ICity, State. Zip I 0 PI d a eif d ' tI 0 Please send a gifl card in my name. I ease sen a gJ t car In my name.L J

Oh! Young Weatherby is come out of the West,Here is his passion, it brings out his best.And save his good backpack, he gadgets has none,He hikes all alone and he kayaks for fun.But when told of danger to a Wilderness free,He determined to fight, did Young Weathetby.

He stayed not for Watt, he stopped not forReagan,

He swam the Snake River where bridge there was /"none. ;(/

But ere he alighted at BLM's gate,They had consented, for the ga1lanr came late.Laggards in wildlife, dastards in vegetation,Were to mine Wilderness and damn reclamation!

Boldly he .srrode into the BLM ha1l,Among bureaucrats, miners, loggers, and aiLThe craven developers hid 'tween their legs,When up spake the hearing boss, hands on his

regs:'Oh come ye in peace or come ye in perfidy,Or to sneer at our permitting, young Weatherby?'

I long wooed your forest, my suit you did doff,Love swells like the snowpack, but ebbs like

run-off.Now I am come with this lost love of mine,