Idaho State Journal from Pocatello, Idaho • Page 6

PACE SECTION A IDAHO STATE JOURNAL POCATELUO. IDAHO. SUNDAY. JUNE 5. Wl POCATELLO, IDAHO.

A 5, 19" AT 6 Teton Dam--One Year in the Idaho's Worst Man-made Disaster REXBURG, IDAHO Life in Rexburg appears serene today, but on June 5l nearly all of the territory covered in this panorama photo was covered with! ITeton Dam flood water. Ricks College, at the right in this picture, escaped be-J (cause it is on higher ground. (Journal Photos and Stories by O.K. Johnson and Dan Flynn) Experts Agree: Bad Design Led to Teton Dam's Failure EDITOR'S NOTE: Two groups investigaled Ihe failure of the Teton Dam, a nine-member independent panel and a federal government review group. Wallace L.

Chadwick, was chairman of the independent panel charged by the secretary of the Interior and the governor of Idaho to review Ihe cause of the dam's collapse. The panel's meetings were closed to the public and the news media. Its findings were made public in January. The Department of the Inlerior Telon Dam Failure Review Group's invesligation was open to Ihe public and Ihe news media. The Inlerior Review Group (IRG) was chaired by Dennis N.

Sachs, Ihen depuly assislanl secrelary of Ihe Interior for Land and Water Resources. F. William Eikenberry was chairman when the IRG issued ils final report in April. Both groups used the same data and reached similar conclusions, lhal improper design resulted in Ihe dam's failure. Following is a summary of Ihose conclusions.

TETON DAM WAS CONSTRUCTED according to specifications and failed because of inadequate protection of the core material from internal erosion, according to The mosl likely source of failure was cracking of Ihe impervious core that allowed erosion lo start. However, Ihe erosion could have been slarled by piping, where lhal material and the rock surface met. is erosion by percolating water in soil, resulting in caving and the formation of narrow conduits, tunnels, or pipes through the soil). "The bureau had the necessary information available to develop an adequate defensive design," Ihe IRG reported. "A safe dam could have been buill al Ihe site utilizing design concepts thai were known at Ihe lime." THE SITE SELECTION procedures were said adequate, wilh the existing site the best of available alternative sites for Ihe purpose of the dam.

In the opinion of IRG, enough geologic data were ob- lained for a proper design of Ihe dam. Reliance on the groul curtain for total control of damaging seepage inhibited adoption of older design fealures lhal could have prevented the failure, IRG said. (A grout curtain is a curtain-shaped zone of rock or soil treated by grout injected into holes to reduce the amount of water seepage through rock or soil. Groul is a runny cemenl fluid enough lo be poured or injected inlo spaces lo fill or seal them.) "THE DESIGN FAILED lo provide a defense againsl Doth flow through embankment cracks and erosion of the zone one impervious core at rock surfaces," Ihe IRG reports. "Defensive measures, such as rock surface sealing and adequate fillers, were well wilhin Ihe slale-of-lhe-art at the time Teton Dam was designed and should have been used," According to IRG, Ihe design incorporated a fealure, Irenches in abutments, thai significanlly departed from pasl" Bureau of Reciamalion procedures.

(A key Irench is a deep, narrow Irench eul Inlo a dam foundalion lo cul off water flow). THE GEOMETRY OF THE abudmenl key Irenches was conducive lo developing slress palterns that could have allowed the impervious core to crack. The narrow widlh of Ihe sealed foundalion rock al the bottom of the key trench, combined with the high permeability of the rock foundation on either side ol the key trench, produced steep hydraulic gradients across the Irench. The IRG notes recognition of the possibility of hydraulic fracluring was not in the general slale-ol-lhe-arl of dam design at the time Telon Dam was designed. However, Ihe polenlial for cracking from earth fill settling at different rates near Ihe steep abutmenls and key Irenchss wilhin Ihe abulmenls has been recognized by dam designers in Ihe pasl, IRG said.

An independenl review of Ihe design might have iden- lified the design deficiencies, according lo IRG. IRG FOUND THE TETON construction practices in agreement with general practices and procedures followed in earth dam construction. Control tesling was found lo be adequate and followed generally accepted procedures. On operation of Ihe reservoir, IRG staled: "The relation of Ihe high rale of filling of Ihe reservoir lo Ihe failure is indeterminate. The facl lhal Ihe main river outlet works was not available to assist in controlling rate of storage is judged lo have no significanl effecl on the ultimate failure of Teton Dam." The independent panel agreed Ihe rate of filling the reservoir was not the cause of the dam's failure.

The panel believes a slower rate would have delayed the failure, but a failure would have occurred later. THE INDEPENDENT PANEL cited a combination of geological factors and design decisions as the fundamental cause of Ihe Telon Dam's collapse. Numerous open joinls in Ihe abulment rocks and. the scarcily of belter materials for the impervious zone of the dam more lhan Ihe highly erodible and brillle windblown soils, were found by Ihe panel lo be the principal geologic factors conlributing to the failure. The IRG took exception to the panel's view of the core material, saying: "Safe dams have been constructed using this material, and Ihe basic concepls for a defensive design were well wilhin the state-of-the-arl during Ihe design of Ihe Telon Dam." "Of paramount importance was Ihe proleclion of this sill from piping and erosion," IRG reported.

"This proleclion had lo be provided lo prevent.migration of sill particles as water percolated Ihrough il (piping) and next lo il (erosion)." DISCUSSING DESIGN MISTAKES, the panel cites four problem areas: (1) complete dependence for seepage conlrol on a combination of deep key Irenches filled wilh windblown soils and a groul curtain; (2) seleclion of a geometrical configuralion for Ihe key Irench lhat encouraged arching, cracking, and hydraulic fracluring in Ihe brillle and erodible backfill; (3) reliance on special compaction of the impervious materials as Ihe only proleclion against piping and erosion of material along and into open joinls, except some of Ihe widesl joinls on the face of the abutmenls downslream of Ihe key Irench where concrete In-filling was used; and (4) inadequate provisions collection and safe discharge of seepage or leakage which inevitably would occur through the foundation rock and culoff systems. "INSTEAD OF PLACING so much dependence on Ihe key Irenches and grout curtain, measures should have been developed to render harmless whatever water did pass, irrespeclive of Ihe reasons," Ihe panel concluded. The IRG is continuing ils investigation wilh work Ihis summer al Ihe dam sile. The groul curtain, the left abulmenl and embankmenl, and additional finite element studies are underway. The Interior Departments task force has, however, made recommendations that might prevent other dam failures.

Among those suggestions: An independent board of review should be convened for each major dam project to study both Ihe design and conslruclion al appropriate intervals; design decisions should be formally documented; design personnel should remain actively involved with a project during construction, including frequenl sile major dams and their foundations should include an instrumentation program lo monitor construction and post- construction behavior. Idaho's devastated Teton Dam, as it looks today with the Teton River meandering through its broken foundations. Experts conclude the massive earth-fill structure failed because of improper design. It Was a Long Day for Austin This deep canyon below the Teton Dam kept the flood wafers in a channel, preventing them from striking the farm community of Newdale just four miles away. ST.

ANTHONY-June 5, 1976 started out like any other Saturday for Ted Austin. But before the day was over, he would save Ihe lives of dozens, maybe even hundreds of people. Austin is a radio announcer for KIGO here. He watched Ihe Teton Dam crumble away and used a telephone lo air warnings lo Ihose downstream to evacuate. Like mosl Salurdays, Austin was off and al home lhal day doing Ihings around the house.

Thomas F. Stegelmeier, Fremont County sheriff, called to inform Austin of the leak at the dam. Earlier, Robert R. Robison, projecl conslruclion engineer, had contacted Ihe sheriffs of Madison and Fremont counties about the leak. That call came at 10:43 a.m.

But, neither Stegelmeier nor Austin could decide what the news of the leak meant. So Auslin called Robison himself for a statement Robison lold Ihe radio newmen of Ihe leak, bul said he had a crew working on it trying to open a diversion lunnel. Auslin broadcasl Robison's warning lhal Ihe Telon River mighl rise because of opening of the diversion canal. Based on Robison's stalemenl lhal he "had a crew working on il," Austin's immediate concern evaporated. Bul Craig Rineharl, a depuly sheriff, arrived a few minutes later' "Why don't we go out there and see what the situation is?" Rinehart asked.

So Auslin joined the lawman in a irip lo Ihe dam. "Whal we saw was very disturbing, but not very conclusive," Austin told the Journal. There was a wet spot down low on the dam. Austin's concern, however, was that dirt on the face of the dam was falling down into the hole meaning il was climbing up Ihe north side of the dam. The newsman and the deputy asked what was going to happen.

They did not gel a conclusive Indication. Workers at Ihe dam site shurgged (heir shoulders when pressed and Ihey couldn'l find Robison. "So we walched Ihis gradual deterioration untiflhc point came when il was obvious Ihe dam itself was going to be damaged," Austin said When (he hole crept under the roadway over the dam, Austin went on the air via telephone from the dam to broadcasl what ne saw. Il still wasn't clear what was going to happen, and Bureau of Reclamation personnel never gave Austin nor Rinehart any further warnings lo issue. The only Indication Austin had thai the water was Koine to breach the dam came from an unidentified man he Ihinks was an engineer.

Passing in a truck, Ihe man yelled "It's Just eight to ten minutes before the water poured over the top of the dam, Austin changed his position on the air based on the shouted warning. The St. Anthony radio station told downslream residenls to gel out. While ordering evacuation for Ihe populated downslream area, Auslin says he didn'l really have anylhing lo go on. He wasn'l sure who should evacuate nor how far Ihey should go.

In minutes a wall of waler that Austin estimated to be 60 to 80 feet high was washing into the canyon. Austin Ihinks residents closer lo Ihe moulh of Ihe canyon who heard his broadcast had less lhan 3D minutes lo run for higher ground. When Ihe water deslroyed Ihe power house below Ihe dam, Austin's phone line wenl dead. Bolh Auslin and Rineharl were sure Telon cily would be wiped out. So Ihey wenl lo warn Ihe residenls.

Rineharl left Austin there and drove on to warn Wilford 'residents whose homes were later wiped out. Left in the middle of the street at Telon with no Iraffic Auslin said he fell "a little bil hopeless." Of course, Ihe water- passed jusl north of Teton. There Austin saw" the water "picking bridges We children's loys" and tearing concrete abutmenls oul of Ihe ground in seconds. An orange Volkswagen was riding on Ihe fronl of Ihe wave. He never did see it go under.

Austin'wenl back on the air "in bils and pieces" from telephones thai he could nol lie up. Meanwhile Ihe SI An Ihony and Rexburg radio stations became centers for emergency messages. Auslin finally made it back to the station late in Ihe afternoon. Recalling Ihe day, Auslin said, "We never received a warning of exlreme danger." Until Rinehart arrived Auslin wasn'l even considering Roing up too the dam. Auslin feels badly lhal Ihose al the dam didn'l give earlier more specific evacuation orders.

If everyone evacuated and Ihe crews saved Ihe dam, Ihey would have been heros, Auslin sntcl. FOOTNOTE: In a statement to special agents of the In lenor Department, Robison staled: "At about 10 30 to10 45 a.m., I notified Ihe sheriff's offices in Madison and Fremont counties and advised them to alert citizens of potenlla flooding from Ihe Telon Dam and to be prepared to evacuate (he area downstrea. I also received a call from Ted Austin a radio announcer in St. Anthony, Idaho and advised him of the possible danger. There was no equivocation on my part about advising people of Ihe danger at this time." Vcrnmenl inws Krs have never contactw No Finger in the Dike Could Have Stopped It! Erwin Allen might have the seeds of a new disaster film by reading part of the Interior Review Group's report on the June 5, 1976 failure of the Teton Dam which includes a chronology of events that resulted in the massive flooding.

The Bureau of Reclamation began construction of the Lower Teton Division in 1972. On Oct. 3,1975, the BOR began filling the reservoir behind the dam. Water continued to fill in behind the dam at a relatively slow rate until April 10,1976. Water behind the dam at that time was 120 feet deep.

There were no problems with the enbankment 'nor with seeps or leakage. AFTER APRIL 10, the reservoir began filling at a faster rate because of the high runoff of snowmelt. But, prior to June 3, 1976, there were no problems with the enbankment nor seeps. With 240 feet of water behind the dam, project personnel inspecting the right abutment on June 3,1976 found two small seeps located 1,300 and 1,500 feet downstream from the toe of the dam. THE SEEPS WERE LIKE small clear water springs with flows estimated at 60 and 40 gallons per minute, respectively.

1 The next day, another small, clear seep was located about 150 to 200 feet downstream from the toe of the dam. Its flow was less, about 20 gallons per minute. No additional seeps were found as of 9 p.m. on June 4. Fifteen hours before the waters would breach the Teton Dam, no leaks had yet been located on the enbankment or the abutments.

A BOR employe was at the damsite until 12:30 a.m. on June 5. ON THE FATEFUL DAY of Saturday, June 5, 1976, a survey party spotted another leak. Observed at 7:45 a.m. this seep as located on the right abutment itself, near the toe of the dam.

Others of the 41 eyewitnesses interviewed by special agents of the Interior Department, reported yet another leak at about the same time 155 feet higher on the dam. The survey party reported the first leak to their supervisor who examined it at 8:15 a.m. He estimated the flow at 20 to 30 cfs. Four hours later, a big chunk of the Teton Dam would no longer exist. The IRG noted that contract personnel were probably the first to notice the water flowing from the abutment at about 7 a.m.

At 8:20 a.m., the project construction engineer and the field engineer were notified of the seepage. They arrived at the damsite at 9 a.m. They didn't know it, but time was getting very short. ROBERT R. ROBISON, project construction engineer, and Peter P.

Aberle, field engineer, walked the downstream face of the dam near the right abutment lo the embankment. No leakage was observed from the crest' of the dam to that point. At 9:10 a.m., a slightly turbid leak of two cfs was spotted exiting from the abutment. The water flowed for a short distance along the contact before entering the en- bankment rockfill. According to the IRG, waterflow from that leak during the early morning hours June 5 had evidently washed away finer material overlying the rockfill along the entire en- bankment-abutment contact for about 159 feet, raising the possibility the flow was greater before Robison and Aberle saw it.

They did not see the leak some witnesses said was higher up on the dam. However, they did find the lower leak observed by the survey party on the abutment near the toe of the dam. At 9:30 a.m., the engineers estimated the leak flowing at 40 to 50 cfs. The IRG noted the estimates were crude and did not indicate a massive increase in the flow since 8:15 a.m. when the survey parly supervisor thought the flow was about 20 to 30 cfs.

AFTER PHOTOGRAPHS WERE taken, Robison and Aberle returned to the project office where they gave instructions to channel the leakage from the abutment near the toe of the dam. Between 10 a.m. and 10:30 a.m. a wet spot developed on the downstream face of the dam about 150 feel higher up than the earlier leak. The wet spot was 15 lo 20 feel out from Ihe righl abulmenl.

The wet spol began to leak and erode. Then, signaling Telon Dam's impending death, those al Ihe sile heard a loud sound followed by Ihe sound of rapidly running waler. "This leak developed almost instantaneously at about 10:30 a.m. and let loose'with a loud roar," Robison said. From that time the water flow and erosion increased at a rapid rate.

TWO BULLDOZERS WERE SENT to the right abutmenl at 10:40 a.m. to begin pushing rock into the eroding hole. At 10:40 a.m. Robison called Madison and Fremont county sheriffs wilh the warning that downstream areas should be evacuated. Robison also talked with Ted Austin, announcer for Radio Slalion KIGO al St.

Anthony, about the flooding danger from the dam's failure. With the dozers working, Robison again walked down the right abutment and looked directly into the opening in the face of his dam. He saw a tunnel 30 to 40 feel long and roughly six feet in diameter extending inlo Ihe enbankment. ROBISON TOLD THE IRG, was coming out of a circular hole through the embankment at right angles to axis of the dam." The dozers had worked for 20 to 30 minutes when the one closest to the eroding hole could not get enough traction to back away from the edge. The other dozer hooked onto It In an attempt to pull it back.

Since 11 a.m., a whirlpool was in progress in the reservoir 15 to 20 feet upstream from the dam's face. The whirlpool was about 150 feet from the right abutment surface contacl with its diameter expanding quickly. Efforts were made to push rock into the whirlpool with no apparent effect. At 11:30 a.m., with Ihe operalors fleeing on foot for their lives, the two bulldozers slid Into the opening they were trying to conlrol and were washed down stream. Between 10 and 20 minutes later, another sinkhole appeared 115 feet higher on the downstream face of the dam's embankment.

MINUTES LATER AT 11:55 a.m., the embankment crest collapsed. Water breached the Teton Dam at 11:57 a.m., June 5,1976. Potato Farmers Hurt By Loss of Irrigation ST. ANTHONY-Irrigators here were counting on the slorage capacity of the Teton Dam Reservoir for spud water Ihis summer. But when the Teton Dam failed'one year ago loday, all of lhal water was lost.

Irrigators now face the prospect of a drought, and chances of re-building the Teton Dam in the near future are slim. FLOOD WATER RIPPED up many canals in the area downstream from the dam, but a Bureau of Reclamation rehabilitation project has restored them. Between 16,000 and 20,000 head of livestock were lost and up to 100,000 acres of prime agricullural lands were inundated. Estimates are that 3,000 to 10,000 acres of that land are not capable of being restored to full productivily. The flood washed away Ihe lop soils and lefl rocks, sand, and gravel Ihroughoul many fields However, on 90 per cenl or more of Ihe lands affecled by the flood, restoration has worked "II was silled up pretty bad, bul it's plowed up real nice," said one farmer.

RODNEY DALLING, who farms about 600 acres of land between Rexburg and Sugar City echoes the feelings of mosl farmers in Ihis area. Asked if he wanted the Teton Dam rebuilt, he replied, "You bet! Irrigators are already on record as supporting the construction of a new Teton DanV Cy Young, of the North Fork Water Users Association says their local group and the Dislricl One Waler Users bolh wenl on record lasl winter with a resolution asking for conslruclion of a new dam on the Teton River North Fork water users presently have 46 per cenl of Ihe water normally available by Uri. time of year, Young said. On the Teton watershed, the figure is 53 per cenl of normal. MANY CANALS HAVE BEEN on storage water since early spring.

Speaking the Teton Dam reservoir, Young said That IfltoSo or 300,000 acre feet would have been aw ully good." Losing the dam means the loss of acres of usable feel yearly, Young droughl conditions. Young said there was no high water this year first time over the years thai we lost the water before the ardor he said Natural flow rights ended on he Last Chance Canal on April ve been on storage water, me lime when Irrigators really wnter, Young added. snvs certainly helped. Young says. need the was a iilesaver here, not only for the dry farmers, but the irrigation farmers as well." WHILE HIS ASSOCIATION favors rebuilding the Teton Dam, Young thinks flood victims should have a voice in the matter, too.

"I Ihink before Ihe Telon Dam is given serious consideration for rebuilding, Ihe people lhal sustained serious damage should have their inpul," Young said. "It's only Mosl farms in the area are family owned. Polaloes, barley, alfalfa, and sugar beels are among the crops grown in Ihe region. The Fremonl-Madison Irrigation Dislricl conlracted for irrigation slorage in Ihe Telon Reservoir. Kellh Bean, office manager for Ihe dislricl, said "Aclually we're in a lillle belter shape lhan if this drought had occurred before Ihe flood." THE REASON FOR BEAN'S slalemenl is farmers have been pulling in many sprinkler systems since the dam collapsed.

And sprinklers use less water than dilch irrigation. "II slill doesn't pul us in very good shape," Bean added. Farmers in Ihe dislricl now irrigate 120,000 acres. The canal system lhal feeds Ihe dislricl uses waler from Ihe Island Park Reservoir. Asked aboul current crop conditions, Bean said, "Up here righl now Ihings are looking prelly good because of Ihe rain.

However, Ihey are going lo have lo slarl watering now. Especially wilh Ihe warm weather." "WITH THE WARM WEATHER, Ihe demand for water is really going to go up," he siad. Bean also favors conslruclion of a new Telon Dam.Irrigalors are nol pushing il now with a great deal of publicity, because they want lo "lei Ihe memory of Ihe flood pass a liltle bit," Bean said. But, the droughl might provide Ihe climalc- for starting a campaign for rebuilding the broken structure, he continued. The Bureau of Reclamation which built the ill-fated slructure in (he firsl place starts now from square one.

Robert Robison, projecl construction engineer, said the bureau will study the feasibility and need lor a new dam jusl as Ihey do wilh every olher project. If they decide it's needed, lhey'11 ask Congress for the funds. HOWEVER, THE CARTER Administration has been axing water projects like a spring chicken kill. With Ihe administration's opposition to projects that have marginal cost-benefit ratio or a negative environmental impact, Telon Dam Is likely to remain as a crumbled monument lo failure for some lime. Robison and Captain Of the USS Titanic Have Lot in Common Rodney Dalling, who farms about 600 acres between Rexburg and Sugar City, says he wants the Teton Dam rebuilt.

He echoes the feelings of many farmers in that area. Some might say Robert Robison and captain of the U.S.S. Titanic have a lol in common. Robison, projecl conslruction engineer for the Telon Darn, is still al the helm of Ihe ill-fated federal struclure, bul he'll be moving on soon. So will everybody else.

The $60 million Telon Dam will soon be deserled. Robison has been named regional engineer for Ihe Federal Bureau of Reclamation's Norlhwesl Region, a lateral move al Ihe same civil service grade. Because Iwo panels have agreed Ihe dam's design was at fault, nol Ihe construction procedures, Ihe projecl conslruclion engineer was not held responsible for Ihe dam's collapse. Bul, more than any olher single individual, the Telon Dam was Robison's baby. If he feels cheated or deceived by bureau designers who planned Ihe unsafe dam lhal killed 11 people and caused $500 million in damage, he is not saying anything about it.

At Ihe dam site this week, Robison explained that exploration into the cause of the failure continues for the Interior Review Group still studying Ihe collapse. Aboul one million cubic yards of material will be excavated from the left dam abutmenl thai survived the collapse, Robison told Ihe Journal. The material will undergo laboratory studies for moisture and density. Investigators hope more conclusive statements can be made about the dam's failure after Ihe excavation. Robison said work will continue down to the key trench located under the dam.

He expects to continue through this construction season only. All of the work that remains will be on the left abutment, except for some diamond drilling and water testing across the canyon on the right abulment. "There's a lot of similarity between the two sides," Robison said. He hopes the additional work will "shed more lighl on the reasons for the failure." Asked about conclusions of the investigating panels, Robison said: "Most of the conclusions, I agree with." The panels did "a tremendous job," according to Robison. Reflecting on the pasl year.

Robison said it has been a busy one. The bureau worked to put the canals torn up by the flood waters back into operation and did the legwork at the dainsitc for the investigating groups. Asked about the future of the Teton Dam, Robison said bureau policy is to start again at the beginning wilh studios of Ihe feasibility and need. After complete research, the findings are presented to Congress. Robison responded to a question about whether Ihe Carter Administration's waler projecl policy mighl have an impact on Teton's fulure.

"I'm sure il will. The Carter policy will have a definite effect on the future of Teton." The Interior Review Group has recommended an independent panel review all dam designs in the future. "That's a good move," Robison said. The IRG has also suggested designers spent more time on the site during conslruction. That's "real excellent," Robison added.

Those are the "pluses lhat have come as a result of it," Robison said, referring to the June 5, 1976 collapse of the Teton Dam. His dam. Robert Robison Still at the Helm.