Teton Dam
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The Teton Dam was an
earthen dam An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil or rock. It has a semi-pervious waterproof natural covering for its surface an ...
in the
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United States, on the Teton River in
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Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...
. It was built by the U.S. Bureau of Reclamation, one of eight federal agencies authorized to construct dams.Perrow, Charles. ''
Normal Accidents ''Normal Accidents: Living with High-Risk Technologies'' is a 1984 book by Yale sociologist Charles Perrow, which provides a detailed analysis of complex systems from a sociological perspective. It was the first to "propose a framework for charac ...
''. New York: Basic Books, 1984. , pp.233–238
Located between Fremont and
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counties, it suffered a catastrophic failure on June 5, 1976, as it was filling for the first time. The collapse of Teton Dam resulted in eleven deaths, and killed 16,000 livestock. The dam cost about $100 million to build and the federal government paid over $300 million in claims related to its failure. Total damage estimates have ranged up to $2 billion, and the dam was not rebuilt.


History and geology

Interest in building a dam in the eastern Snake River Plain had arisen for many years to control spring runoff and provide a more constant water supply in the summer. The area had suffered a severe drought in 1961, followed by severe flooding in 1962. The Bureau of Reclamation proposed the Teton Dam in 1963 and
Congress A congress is a formal meeting of the representatives of different countries, constituent states, organizations, trade unions, political parties, or other groups. The term originated in Late Middle English to denote an encounter (meeting of a ...
passed without opposition an authorizing bill the following year. The planned dam was to be an earthen structure high and long and create a
reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...
in length. The impounded water would be used to generate
hydroelectric power Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...
. An environmental impact statement was issued for the dam in 1971, but it did not raise the possibility of a collapse. Lack of funding and site preparation work and questions surrounding the required environmental impact statement stalled the project. Barely 14 pages long, the statement quickly drew the ire of opponents of the project. On September 27, 1971, several environmental and conservation groups filed a lawsuit in Idaho District Court to stop the construction. Opponents of the dam questioned the project's justifications. They argued that damming a wild and scenic river and destruction of its trout fishery and other wildlife habitat would "replace a unique resource with a vulgar one." The suit questioned the economic return on investment, the bureau's compliance with the National Environmental Policy Act, and the geologic soundness of the dam's location. Concerns over the seismic conditions of the dam site delayed the bid process pending further review by the Department of the Interior. Pressure from Idaho's congressional delegation stopped the review, and in spite of the lawsuit, bids were taken in Idaho Falls on October 29, 1971. The contract was awarded to Morrison-Knudsen Co. of
Boise Boise (, , ) is the capital and most populous city of the U.S. state of Idaho and is the county seat of Ada County. On the Boise River in southwestern Idaho, it is east of the Oregon border and north of the Nevada border. The downtown area' ...
, assisted by Peter Kiewit Sons Co. of
Omaha, Nebraska Omaha ( ) is the largest city in the U.S. state of Nebraska and the county seat of Douglas County. Omaha is in the Midwestern United States on the Missouri River, about north of the mouth of the Platte River. The nation's 39th-largest cit ...
. The $39 million contract was awarded in December 1971. In spite of the lawsuit, work began in February 1972. After various motions, amended complaints, attempted injunctions, and appeals, the suit was dismissed on December 23, 1974. The eastern Snake River Plain is almost entirely underlain by
basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
erupted from large
shield volcano A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more v ...
s on top of
rhyolitic Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...
ash Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...
-flow
tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...
and
ignimbrite Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrou ...
s. The
tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...
, a late-
Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...
rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...
is 1.9 million years old. The dam site is composed of basalt and rhyolite, both of which are considered unsuitable for dam construction because of their high permeability. This was confirmed by long-term pump-in tests at rates of per minute.Arthur, H. G., 1977. Teton Dam Failure, pp. 61–71, in The Evaluation of Dam Safety (Engineering Foundation Conference Proceedings, Asilomar, Nov. 28 – Dec. 3, 1976), American Society of Civil Engineers, New York, 523 p. Edited version: http://sylvester.faculty.geol.ucsb.edu/Teton_Dam/narrative.html Test cores, drilled by engineers and geologists employed by the Bureau of Reclamation, showed that the canyon rock at the dam site is highly fissured and unstable, particularly on the right side (as one faces the direction of flow). The widest fissures were determined to be wide. The bureau planned to seal these fissures by injecting grout into the rock under high pressure to create a
grout curtain A grout curtain is a barrier that protects the foundation of a dam from seepage and can be made during initial construction or during repair. Additionally, they can be used to strengthen foundations and contain spills. Characteristics A grout curt ...
in the rock. In addition, an investigation of the area by geologists of the U.S. Geologic Survey indicated that it was seismically active; five earthquakes had occurred within of the dam site in the previous five years, two of which had been of significant magnitude. This information was provided to the Bureau of Reclamation in a memorandum, but the geologists' concerns were considerably watered down in the 6-month redrafting process before the USGS sent the final version of the memo to the USBR in July 1973. In 1973, when the dam was only half built, but almost $5 million had already been spent on the project, large, open fissures were encountered during excavation of the keyway trench near the right end of the dam, about from the canyon wall. The two largest, near-vertical fissures trended generally east-west and extended more than below the bottom of the key trench. Some of the fissures were lined with calcite, and rubble filled others. Several voids, as much as wide, were encountered below the ground surface beyond the right end of the dam and grout curtain. The largest fissures were actually
caves A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...
. One of them was wide and long. Another one was wide in places and long. These were not grouted because they were beyond the keyway trench and beyond the area where the bureau had decided grouting was required. This necessitated using twice as much grouting as had been originally anticipated; the total injected grout included 496,515 ft3 of Portland cement, 82,364 ft3 of sand, 132,000 pounds of bentonite, and 418,000 pounds of calcium chloride, injected into 118,179 linear ft of drilled holes. Later, the report of a committee of the
House of Representatives House of Representatives is the name of legislative bodies in many countries and sub-national entitles. In many countries, the House of Representatives is the lower house of a bicameral legislature, with the corresponding upper house often c ...
, which investigated the dam's collapse, felt that the discovery of the caves should have been sufficient for the Bureau of Reclamation to doubt its ability to fill them in with grout, but this did not happen. Even after the dam had failed, the bureau continued to insist that the grouting was appropriate. In December 1972, concerned about the geological conditions of the Teton River Canyon, USGS geologist David Schleicher wrote about the Teton Dam while it was still under construction, "A final point is that flooding in response to seismic or other failure of the dam—probably most likely at the time of highest water—would make the flood of February 1962 look like small potatoes. Since such a flood could be anticipated, we might consider a series of strategically placed motion-picture cameras to document the process."


Filling

The dam was completed in November 1975 and filling the reservoir began at the standard rate of a day. However, snows were heavy that winter, and five months later, the project's construction engineer requested permission to double the filling rate to deal with the additional spring run-off, while continuing to inspect for leaks and monitor the groundwater. A month later, though monitoring showed that groundwater was flowing a thousand times faster than had been originally anticipated, the filling rate was doubled again, to a day. On June 3 and 4, 1976, three small springs were discovered downstream of the dam, although the water running through the leaks was clear and such leaks are not unexpected for an
earthen dam An embankment dam is a large artificial dam. It is typically created by the placement and compaction of a complex semi-plastic mound of various compositions of soil or rock. It has a semi-pervious waterproof natural covering for its surface an ...
. At the time, the reservoir was almost at capacity, with a maximum depth of . The only structure that had been initially prepared for releasing water was the emergency
outlet works A gatehouse, gate house, outlet works or valve house for a dam is a structure housing sluice gates, valves, or pumps (in which case it is more accurately called a pumping station). Many gatehouses are strictly utilitarian, but especially in the n ...
, which could carry just . The main outlet works and spillway gates were not yet in service; the gates were cordoned off by steel walls while they were being painted.


Collapse and flood

File:Teton_Dam_Sequence_00.jpg, The dark brown streak on the dam face near the gray bedrock in the left half of the photo is a leak that formed on the morning of June 5. The speck above the leak near the top of the dam is a D9 bulldozer on its way to push soil into the leak. File:Teton_Dam_Sequence_03.jpg, Large amounts of mud are now spilling down the face of the dam, unchecked by the efforts of the bulldozer operators. The outlet works at the foot of the dam are flooding with muddy water. File:Teton_Dam_Sequence_08.jpg, The dam is now breached and muddy water flows violently over the dam face. File:Teton_Dam_Sequence_13.jpg, The breach has now widened to nearly its full extent. The outlet works are completely inundated with muddy water. On Saturday, June 5, 1976, at 7:30 am MDT, a muddy leak appeared, suggesting sediment was in the water, but engineers did not believe there was a problem. By 9:30 am, the downstream face of the dam had developed a wet spot, which began to discharge water at and the embankment material began to wash out. Crews with
bulldozer A bulldozer or dozer (also called a crawler) is a large, motorized machine equipped with a metal blade to the front for pushing material: soil, sand, snow, rubble, or rock during construction work. It travels most commonly on continuous track ...
s were sent to plug the leak, but were unsuccessful. Local
media Media may refer to: Communication * Media (communication), tools used to deliver information or data ** Advertising media, various media, content, buying and placement for advertising ** Broadcast media, communications delivered over mass e ...
appeared at the site and at 11:15, officials told the county sheriff's office to evacuate downstream residents. Work crews were forced to flee on foot as the widening gap, now larger than a swimming pool, swallowed their equipment. The operators of two bulldozers caught in the eroding embankment were pulled to safety with ropes. At 11:55 am MDT (UTC−17:55), the crest of the dam sagged and collapsed into the reservoir; two minutes later, the remainder of the right-bank third of the main dam wall disintegrated. Over (many times the average flow rate of
Niagara Falls Niagara Falls () is a group of three waterfalls at the southern end of Niagara Gorge, spanning the border between the province of Ontario in Canada and the state of New York in the United States. The largest of the three is Horseshoe Falls, ...
) of sediment-filled water emptied through the breach into the remaining of the Teton River canyon, after which the flood spread out and shallowed on the Snake River Plain. By 8:00 pm, the reservoir had completely emptied, although over two-thirds of the dam wall remained standing.


Cause

Study of the dam's environment and structure placed blame for the collapse on the permeable
loess Loess (, ; from german: Löss ) is a clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth's land area is covered by loess or similar deposits. Loess is a periglacial or aeolian ...
soil used in the core and on fissured (cracked) rhyolite in the abutments of the dam that allowed water to seep around and through the earth-fill dam. The permeable loess was found to be cracked. The combination of these flaws is thought to have allowed water to seep through the dam and to lead to
internal erosion Internal erosion is the formation of voids within a soil caused by the removal of material by seepage. It is the second most common cause of failure in levees and one of the leading causes of failures in earth dams, responsible for about half of ...
, called piping, that eventually caused the dam's collapse. An investigating panel had quickly identified piping as the most probable cause of the failure, then focused its efforts on determining how the piping started. Two mechanisms were possible. The first was the flow of water under highly erodible and unprotected fill, through joints in unsealed rock beneath the grout cap and development of an erosion tunnel. The second was "cracking caused by differential strains or hydraulic fracturing of the core material." The panel was unable to determine whether one or the other mechanism occurred, or a combination:
The fundamental cause of failure may be regarded as a combination of geological factors and design decisions that, taken together, permitted the failure to develop.
A wide-ranging controversy ensued from the dam's collapse. According to the Bureau of Reclamation, bureau engineers assess all reclamation dams under strict criteria established by the Safety of Dams program. Each structure is periodically reviewed for resistance to seismic activity, for internal faults, and for physical deterioration. The dam safety program identified two other dangerous dams – Fontenelle, which very nearly failed 11 years earlier, when it was filled, in a manner similar to the Teton Dam, and again in May 1985; and the
Jackson Lake Dam Jackson Lake Dam is a concrete and earth-fill dam in the western United States, at the outlet of Jackson Lake in northwestern Wyoming. The lake and dam are situated within Grand Teton National Park in Teton County. The Snake River emerges from ...
, which would have failed during an earthquake on the nearby
Teton Fault The Teton fault is a normal fault located in northwestern Wyoming. The fault has a length of 44 miles (70 km) and runs along the eastern base of the Teton Range. Vertical movement on the fault has caused the dramatic topography of the Teton R ...
.


Deaths, damage, and property claims

Teton Canyon ends about below the dam site, where the river flows onto the Snake River Plain. When the dam failed, the flood struck several communities immediately downstream, particularly
Wilford Wilford is a village in the city of Nottingham, Nottinghamshire, England. The village is to the northeast of Clifton, southwest of West Bridgford, northwest of Ruddington and southwest of Nottingham city centre. It is at a meander of the Rive ...
at the terminus of the canyon, Sugar City, Salem, Hibbard, and
Rexburg Rexburg is a city in Madison County, Idaho, United States. The population was 39,409 at the 2020 census. The city is the county seat of Madison County and its largest city. Rexburg is the principal city of the Rexburg, ID Micropolitan Statist ...
. Thousands of homes and businesses were destroyed. The small agricultural communities of Wilford and Sugar City were wiped from the river bank. Five of the eleven deaths attributed to the flood occurred in Wilford. The similar community of Teton, on the south bank of the river, is on a modest bench and was largely spared. One Teton resident was fishing on the river at the time of the dam failure and was drowned. An elderly woman living in the city of Teton died as a result of the evacuation. One estimate placed damage to Hibbard and Rexburg area, with a population of about 10,000, at 80% of existing structures. The Teton River flows through the industrial, commercial, and residential districts of north Rexburg. A significant reason for the massive damage in the community was the location of a lumber yard directly upstream. When the flood waters hit, thousands of logs were washed into town. Dozens of them hit a bulk gasoline-storage tank a few hundred yards away. The gasoline ignited and sent flaming slicks adrift on the racing water. The force of the logs and cut lumber and the subsequent fires practically destroyed the city. The flood waters traveled west along the route of the Henrys Fork of the Snake River, around both sides of the
Menan Buttes The North and South Menan Buttes in southeastern Idaho are two of the world's largest volcanic tuff cones. The two cones, with four smaller associated cones, align along a north-northwest line and comprise the Menan Complex. The buttes rise abou ...
, significantly damaging the community of Roberts. The city of
Idaho Falls Idaho Falls ( Shoshoni: Dembimbosaage) is a city in and the county seat of Bonneville County, Idaho, United States. It is the state's largest city outside the Boise metropolitan area. As of the 2020 census, the population of Idaho Falls was 6 ...
, even further down on the flood plain, had time to prepare. At the older
American Falls Dam The American Falls Dam is a concrete gravity-type dam located near the town of American Falls, Idaho, on river mile 714.7 of the Snake River. The dam and reservoir are a part of the Minidoka Project on the Snake River Plain and are used primaril ...
downstream, engineers increased discharge by less than 5% before the flood arrived. That dam held and the flood was effectively over, but tens of thousands of acres of land near the river were stripped of fertile topsoil. The force of the failure destroyed the lower part of the Teton River, washing away
riparian zone A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...
s and reducing the canyon walls. This seriously damaged the stream's ecology and impacted the native
Yellowstone cutthroat trout The Yellowstone cutthroat trout (''Oncorhynchus clarkii bouvieri'') is a subspecies of the cutthroat trout (''Oncorhynchus clarkii''). It is a freshwater fish in the salmon family (family Salmonidae). Native only to a few U.S. states, their ...
population. The force of the water and excessive sediment also damaged stream habitat in the Snake River and some tributaries, as far downstream as the
Fort Hall Fort Hall was a fort in the western United States that was built in 1834 as a fur trading post by Nathaniel Jarvis Wyeth. It was located on the Snake River in the eastern Oregon Country, now part of present-day Bannock County in southeastern Ida ...
bottoms. After the dam's collapse, debris clean-up began immediately and took the remainder of the summer. Rebuilding of damaged property continued for several years. Within a week after the disaster, President
Gerald Ford Gerald Rudolph Ford Jr. ( ; born Leslie Lynch King Jr.; July 14, 1913December 26, 2006) was an American politician who served as the 38th president of the United States from 1974 to 1977. He was the only president never to have been elected ...
requested a $200 million appropriation for initial payments for damages, without assigning responsibility for Teton Dam's failure. The Bureau of Reclamation set up claims offices in Rexburg, Idaho Falls, and Blackfoot. By January 4, 1977, disaster victims filed over 4,800 claims totalling $194 million. By that date, the federal government paid 3,813 of those claims, $93.5 million. Originally scheduled to end in July 1978, the claims program continued into the 1980s. At the end of the claims program in January 1987, the federal government had paid 7,563 claims for a total amount of $322 million. No plans have been made for rebuilding the Teton Dam, but its reconstruction has been discussed over the years since its failure. Footage and interviews are featured in ''Catastrophe-No Safe Place'' (1980), hosted by Charles Bronson and
Jill Ireland Jill Dorothy Ireland (24 April 1936 – 18 May 1990) was an English actress and singer. She appeared in 16 films with her second husband, Charles Bronson, and was additionally involved in two other of Bronson's films as a producer. Life and ca ...
.


See also

*
Great Sheffield Flood The Great Sheffield Flood was a flood that devastated parts of Sheffield, England, on 11 March 1864, when the Dale Dyke Dam broke as its reservoir was being filled for the first time. At least 240 people died and more than 600 houses were da ...
*
St. Francis Dam The St. Francis Dam was a concrete gravity dam located in San Francisquito Canyon in Los Angeles County, California, United States, built from 1924 to 1926 to serve Los Angeles's growing water needs. It catastrophically failed in 1928 due to a d ...
, a concrete dam near Los Angeles, which failed in 1928 resulting in over 400 deaths *
Fontenelle Dam Fontenelle Dam was built between 1961 and 1964 on the Green River in southwestern Wyoming. The high zoned earthfill dam impounds the Fontenelle Reservoir. The dam and reservoir are the central features of the Seedskadee Project of the U.S. B ...
, an earthen dam in southwest Wyoming, which partially failed in 1965 but remains in operation


References


External links


Bureau of Reclamation
overview with photos and link t



Eric A. Stene, Bureau of Reclamation History Program, 1996

* ttp://www.rexburghistoricalsociety.com/teton-flood-museum.html Teton Dam Flood Museum, Rexburg, Idaho
Teton Dam Collection – Oral History reports and newspaper articles
includes more than 50 oral history interviews of those living in the area when the disaster occurred.

taken at the time by Mrs. Eunice Olson


Teton River Canyon, ID Teton Dam Collapse and Flooding, Jun 1976
at GenDisasters.com * Johnson, Elaine, "Teton Dam Flood, June 5, 1976" now at http://www.fremont.idgenweb.org/history-flood.html * Watch ''Catastrophe-No Safe Place (1980)'' on the Internet Archive {{Authority control 1976 disasters in the United States 1976 floods 1976 in Idaho Dams completed in 1976 Dam failures in the United States Dams in Idaho Disasters in Idaho Environmental disasters in the United States Buildings and structures in Fremont County, Idaho Buildings and structures in Madison County, Idaho United States Bureau of Reclamation dams