A brief History of: The Teton Disaster (Documentary)

[Music] structural failures can usually be categorized into two groups the first being financial for example cutting corners during construction improper maintenance or just outright corruption but a second category is more psychological and that is constructing whilst ignoring any potential warnings large-scale projects are always susceptible to a type of thinking resulting in construction completion with a safety compromised structure this is known as completion bias and can create a tunnel vision effect where warning signs are missed due to so much time and money being invested in a project a great example of this is in the private pilot realm where the embarrassment or need to reach destination results in continuing to fly in poor or outright dangerous weather conditions which has sadly many a time resulted in disaster the effect has been seen several times in the dam construction industry which have resulted in disasters for example like the violent dam where geological warnings were missed resulting in a catastrophic overtopping and flood today we're looking at the teton dam failure which will result in 11 dead 13 000 cattle killed a hundred million dollars in construction costs and over 300 million dollars in claims for remediation our story starts all the way back into the early 1960s and the perceived need for a new dam to be situated three miles north of new del idaho on the teton river the area had experienced a severe drought in 1961 followed by severe flooding in 1962 and the bureau of reclamation set about to try and tackle this whilst also bringing other benefits of a dam to the region the titan basin project as it was to be known would include a new earthen dam to impound a new reservoir for the generation of electricity flood control irrigation of farmland and recreational activities the reservoir will extend 17 miles upstream holding back around 288 000 acre feet of water with a surface area of 2100 acres the area selected for the new dam was in a canyon that had been carved out by the titan river in the snake river plain the plane was almost entirely underlain by 1.9 million year old bowl salt and rhyolite both of which aren't the best foundation material for a new dam due to their high permeability regardless the bureau of reclamation continued on the project around 100 core drills were bored at a future damn site between 1961 and 1970 and highlighted the need for further investigation of the site some leakage tests were undertaken on the planned right-hand abutment side and showed no water leak from the abutment however the levels of water in the surrounding holes did rise this led to tv camera investigation which showed many cracks and joints of random orientation for the left abutment investigations into its suitability involved grousing into the rock to see the effectiveness of filling the cracks in the foundations initially all seemed acceptable and the information was passed along to the designers of the dam in 1963 the project was authorized and by 1971 after initial planning an environmental impact statement was produced the project would have many objections after this initial statement and this was for many reasons brought by locals and environmental conservationists this was due to the ecological impact on the local area's wildlife as with any filling of a reservoir a large area now finds itself underwater on the 27th of september 1971 several environmental and conservation groups brought a lawsuit in idaho district court to stop the construction amongst the environmental complaints were also a strong economical one stating that the return on investment from the dam wouldn't be all that great not only that but questions were raised over the geological suitability of the area for a dam the law suit and concerns delayed the tender for the construction contract at least for a while but eventually morrison knudsen co of boys assisted by peter kiwitz and sons of omaha nebraska won the bid in december 1971 with initial construction works to begin in early 1972. the suit would be dismissed in 1974 just two years before the disaster but that would only be the start of the warning signs for the suitability of the project but first let's have a look at the design of the teet and dam the plans for the dam were made under the direction of the office of design and construction at the u.s bureau of reclamation at their denver federal center it was to be an earthen type field dam using soil dug from the reservoir location the designers were aware of the surveys which highlighted seepage issues and planned for excavation to groutable rock slush grouting under the core outside the key trenches and downstream holes or tunnels a continuous grout curtain along the entire foundation was to be used extending about a thousand feet into the right abutment and about 500 feet into the left abutment the dam center line was straight for 2000 feet of its length and curved upstream on the right abutment for the last 700 feet also on the right abutment was the spillway which had a gated chute structure with an auxiliary inlet and an outlet for each abutment a trench had to be cut into the rock sides of the canyon there was a river outlet underneath the left abutment which took water from the reservoir bed for use at the pumping and power station the dam's embankment consisted of five zones zone one was the center core and was the largest part which took the longest to construct the center of the dam was a mixture of clay silt sand gravel and cobbles tightly compacted by tamping rollers to form a core this was fought by the bureau of reclamation engineers to be impervious to water next came zone 2 which was placed over the core and composed of sandy gravel compacted to an average relative density greater than 70 zone 2 was extended downstream across the floodplain and on the abutments underlying zone 3. zone 3 consisted of miscellaneous feel zone 4 was similar in construction to zone 2 and served as the upstream cofferdam zone 5 was rockville in the outer parts of the embankment all zones created an overall height of 305 feet above the riverbed right let's get on to the construction which began in february 1972 initially the spillway and key trenches were excavated initially river flow was directed through the middle of the canyon so that excavation could proceed on both abutments after this was completed the river was again diverted into a channel along the right abutment to allow the cut-off trench to the left of the channel to be dug warning signs were found during these initial works as large open fissures were discovered during excavation of the key trench near the right end of the dam several voids were found and had to be filled in with portland cement with some of the fishes actually being caves which resulted in more work than originally thought at this point the structural suitability of the foundation should have come into question but with so much time and money poured into the project so far it just had to be completed the entire embankment foundation was stripped of all unsuitable material including boulders loose rock and topsoil in january 1973 a u.s geological survey team inspected the site and sent a memo to the bureau of reclamation saying safety of the teton dam project is of immediate concern and pressures from the field reservoir and loading could trigger movement that would endanger the dam the bureau's head of design and construction hal g arthur rebutted these concerns asserting that the t10 sites lay in a favorable area from a seismic standpoint which directly contradicted the u.s geological survey during the 1973 construction season the cut-off trench in the river channel was completed as was the grouting in the lower part of the foundation the river was diverted once again through the outlet works on the 8th of june 1973. this diversion enabled construction of the cut-off trench on the right side and the placement of the embankment on the trench towards the end of the year the first of the zone one material was placed in the foundation trench on the third of october 1975 the river was diverted again when the auxiliary outlet was put into operation to enable placement of second stage concrete in the intake and gate chamber of the river outlet and to install outlet gates pipe pen stock manifold and metal work and equipment the zone one area was completed in 1975 allowing the remaining material for the dam's embankment to be placed on top throughout the rest of the year with construction completed in november 1975. with this newly constructed dam the next thing was to fill the reservoir behind it the u.s bureau of reclamation set out to monitor the performance of the foundations and structure during the filling process this was to ensure that the dam was safe for operation part of his monitoring was checking the face of the dam for seepage as well as checking the water board downstream for any abnormal rises the plan was to have the reservoir productive for irrigation in 1976 and open to the public by 1977 with the initial filling rate to begin at one foot per day the reservoir bed was at around 5050 feet in elevation but as the water level rose the reservoir surface elevation would also rise by march the reservoir water surface was at an elevation of 5167 feet the auxiliary outlet was releasing water at 295 cubic feet per second the director of design received a memorandum from the construction engineer that would be worrying well they have been dug for water table observation had shown a significant rise but it was felt that it wasn't anything to worry about as the dam had been inspected and no leaks were found on the 23rd of march the allowable filling rate was increased from 1 to 2 feet per day because the river outlet work was still incomplete and the runoff from the teton river was abnormally high the reason for the high runoff was due to increased snowfall in january that had melted increasing the flow rate the reservoir was allowed to rise in height as a spillway was thought to have been able to handle any flooding from the 11th of may until june the 5th the average rate of rise was at 3 feet per day with a maximum of 4.3 feet on the 18th of may the reservoir level continued to rise up to the maximum depth of 240 feet on the 3rd of june 1976 seepage was discovered in small springs in the right abutment on the downstream toe of the dam they were flowing water at approximately 40 to 60 us gallons per minute what was strange was that the flow of liquid was clear and not brown in color which was more common of erosion on the fourth more leaks were found on the right abutment again flowing clear water at approximately 20 us gallons per minute more seepage was discovered on the 5th of june around 7 30 in the morning but this time the watercolor was that dreaded brownish but due to the clear water before the engineers did not believe there was a problem a wet spot on a downstream face began eroding its way into the embankment on the right side of the dam two bulldozers were sent down to try and fill the leak which is this really small dot on this photo at around 10 40 in the morning an emergency call to prepare for flooding was made to the madison and fremont county sheriff's office at around 11 a.m one of the bulldozers started sliding into the opening the other bulldozer attempted to pull it out between 11 and 11 30 am the project office called the sheriffs again and told them to evacuate the region immediately something that definitely can't be a good thing to see appeared at around 11 30 am and that was an increasingly big whirlpool in the reservoir near the right hand side of the dam the two bulldozers on the embankment started to sink into the opening and both operators abandoned their machines in the meantime two more bulldozers attempted to block the whirlpool by dumping material but this yielded no results the flow for the opening continued to increase until 11 55 am when the dam began to breach at the crest just two minutes later total failure had begun as of reservoir waters broke through the teeth and dam and rolled downstream the water carried away about 4 million cubic yards of the embankment burying the power and pumping plant beneath over 2 million cubic feet per second of water emptied through the breach into the last six miles of the teton canyon from there the flood spread out into the snake river plain a 15 feet high wall of water sped along at around 10 to 15 miles an hour hitting and decimating the towns of wilford and sugar city the water then swept through a log mill which added debris to the flow resulting in the city of rexburg being battered by 8 pm the reservoir had completely emptied leaving around two-thirds of the main dam structure remaining on the 6th of june president gerald ford declared bingham bonneville fremont madison and jefferson counties a federal disaster area 11 people were dead with five of which being wilford residents luckily a higher death toll was averted by the evacuation warning but regardless the property damage was immense which leaves us the question how did this multi-million dollar brand new dam fail immediately after the failure reclamation commissioner gilbert g stam an assistant secretary of the interior arrived in idaho to inspect the site two investigation panels were set up but like most damn failures eyewitness testimony had to be relied upon due to most of the evidence being washed away during the breach however excavations of the remaining parts of the dam did yield some hints at the failure mode a house of representatives subcommittee was also set up headed by leo ryan the same man that would tragically be killed in guyana in 1978 by jim jones followers the hearing and investigations highlighted the dubious selection of the damn sights due to the permeability and porousness of the rock in the valley will likely cause of failure as stated in the independent panel to review the cause of the teeth and dam failure theorise that piping was caused by erosion of the dam by the poorest nature and open joints of the rock at the damn site stating it was recognized by the usbr early in design and confirmed by the panel's investigation that zone one material placed in the key trench and against the abutments was highly erodible as a reservoir level rose the hydrostatic pressures in the upstream jointed rock increased to a point that would have been sufficient to cause hydraulic fracturing resulting in main structure erosion congressman ryan was concerned with a thing he called momentum theory which is similar to completion bias which was endemic in the government organization where the bureau of reclamation had never stopped a project after construction had begun this was especially true for titan where the u.s geological survey had highlighted key faults with the site selection in 1973 but a project already in construction went ahead regardless the speed at which the reservoir was filled became a point of criticism as if the filling had been slower than the near three to four feet per day at its peak then the project employees could have highlighted and fixed any issues but the bureau eager to complete the project allowed for a higher fill rate even though not all the outlets were finished the grout curtain came under criticism as well saying that it was inadequate for its purpose as well as the use of a narrow foundation main trench after excavation of the remains of the dam more wet spots were discovered showing that defenses built into the design to prevent water penetration were inadequate all the investigations came across similar conclusions it is best summed up in the independent panel investigation summary stating the fundamental cause of the failure may be regarded as a combination of geological factors and design decisions that taken together permitted the failure to develop finally saying in final summary under difficult conditions that called for the best judgment and experience of engineering profession an unfortunate choice of design measures together with less than conventional precautions was taken to ensure the adequate functioning of the teeth and dam and these conditions ultimately led to its failure if the bureau had stepped back not focused on the endpoint and taken in the whole picture during construction then maybe they would have seen a dangerous situation they were creating but unfortunately they focused on the destination and not the journey the financial ramifications of the disaster would run into billions and unsurprisingly a number of suits would be brought against the bureau of reclamation before responsibility for the teeton dam's failure was decided a week after the disaster president gerald ford requested 200 million dollars for initial payments for damages the cleanup works began almost immediately but the long-term effects were disastrous the ecosystem downstream from the dam was wiped out affecting trout populations the bureau of reclamation set up offices in rexburg idaho falls and blackfoot for the purpose of people to make financial claims from the government by the end of the process in 1987 over 7 500 claims were made totalling 322 million dollars the dam was never rebuilt and remained a ruin which became a testament to the pitfalls of completion at all costs this video is a plain difficult production all videos on the channel are creative commons attribution share alike licensed plain difficult videos are produced by me john in a kind of sunny southeastern corner of london uk help the channel grow by liking commenting and subscribing check out my twitter for all sorts of photos and odds and sods as well as hints on future videos i've got patreon and youtube membership as well if you fancy supporting the channel financially and all that's left to say is thank you for watching [Music] so

Channel: Plainly Difficult

Views: 1,248,382

Keywords: Teton Dam disaster, Dam failure, Dam Disaster plainly difficult, Plainly difficult documentary, Plainly difficult dam Documentary, teton dam failure, Dam documentary, Plainly difficult, Dam failure documentary, Fascinating horror

Id: rhk8BJIMkLM

Length: 20min 1sec (1201 seconds)

Published: Sat Jun 12 2021