Teton Dam Failure
Image: www.flickr.com/photos/byui_library/4380341098/in/album-72157623364635347
Image: www.flickr.com/photos/byui_library/4380341098/in/album-72157623364635347
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The Teton Dam was built by the U. S. Bureau of Reclamation near Rexburg, Idaho. It was completed in 1976, but the 305-foot-high dam failed catastrophically before it finished filling. When it failed, water in the reservoir was 270 feet deep at the dam. Its 80 billion gallons of water drained at a rate over 1 million cubic feet per second, emptying the reservoir in less than six hours. The disaster killed 11 people and thousands of cattle, destroyed many homes and businesses in multiple towns, left 25,000 homeless, and ravaged 190,000 acres of agricultural land. The collapse led to the establishment of stronger dam safety regulations. The side of the dam that failed was built on highly fractured, permeable welded ash-flow tuff that erupted from Yellowstone 2.1 million years ago.
Teton Dam site is located in eastern Idaho. It was built to prevent seasonal flooding, for irrigation during droughts and to provide hydroelectric power. Prior to its catastrophic breach, it had been filled nearly to capacity.
Image: https://scholarworks.boisestate.edu/under_showcase_2020/177/
Image: https://scholarworks.boisestate.edu/under_showcase_2020/177/
Location of Teton Dam
The Teton Basin Project is in eastern Idaho. Teton Dam was built to serve agricultural lands of the Fremont-Madison Irrigation District, in Fremont and Madison Counties, Idaho. The dam site was near Rexburg on the Teton River, a tributary of the Henry’s Fork of the Snake River. The site was at a narrow point of the Teton River canyon.
These Bureau of Reclamation photos show the Teton Dam site in the canyon of the Teton River before construction began. The first name considered was Fremont Dam, but it was changed to Teton Dam in 1963.
Images: https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Images: https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Directions to Teton Dam Site
The Teton Dam was never rebuilt, but you can still visit its remains at the site. From Rexburg take Highway 20 north to Highway 33. On Highway 33, located 3 miles east of Newdale, a sign indicates the turn to the dam site. The viewing area is 1.5 miles north on 1200 East. Follow the rough dirt road 1/4 mile further east along the rim of the gorge to the end of the dam itself. Be forewarned – there is no restroom.
Geology of Teton Dam Site
The Teton Dam site is in eastern Idaho, southeast of the Snake River Plain and south of the Island Park Caldera, near the northwest end of the Idaho-Wyoming Thrust Belt. Teton Dam was built at a narrow area in the Teton River Canyon on Quaternary volcanic basalt and rhyolitic welded ash-flow tuff.
Annotated portion of Idaho State Geologic Map, with the approximate location of the Teton Dam shown by the red star.
Base Image: Compiled by R.S. Lewis, P. K. Link, L. R. Stanford, and, S.P. Long, 2012, Geologic Map of Idaho. https://www.idahogeology.org/maps-pubs-data/state-geologic-map
Base Image: Compiled by R.S. Lewis, P. K. Link, L. R. Stanford, and, S.P. Long, 2012, Geologic Map of Idaho. https://www.idahogeology.org/maps-pubs-data/state-geologic-map
Combined Geologic Map of Fremont and Madison Counties, Idaho. The Teton Dam Site is at the blue star.
Image: https://digitalatlas.cose.isu.edu/counties/geomaps/geomap.htm
Image: https://digitalatlas.cose.isu.edu/counties/geomaps/geomap.htm
Combined Index to Geologic Map of Fremont and Madison Counties, Idaho.
Image: https://digitalatlas.cose.isu.edu/counties/geomaps/geomap.htm
Image: https://digitalatlas.cose.isu.edu/counties/geomaps/geomap.htm
The basalt on the southeast side of the canyon is part of thick volcanic deposits from the track of the Yellowstone Hotspot in the Eastern Snake River Plain (ESRP). The ESRP is a northeast-southwest trending topographic depression in southeastern Idaho. It extends from the Wyoming border to near Twin Falls, Idaho. It formed as the North American tectonic plate moved southwest over the Yellowstone Hotspot plume. The plume heated and melted the crust, generating multiple zones of magma. The magma in the melted areas fed volcanoes whose eruptions formed a line of calderas that culminate in the Yellowstone Caldera. The calderas formed when the magma chambers erupted, emptied and collapsed.
Beginning about 16 million years ago the Yellowstone Hotspot plume heated the crust, generating zones of magma as the North American tectonic plate moved over it.
Image: National Park Service, undated, Hotspots, https://www.nps.gov/subjects/geology/plate-tectonics-hotspots.htm
Image: National Park Service, undated, Hotspots, https://www.nps.gov/subjects/geology/plate-tectonics-hotspots.htm
The line of calderas along the Eastern Snake River Plain formed when Yellowstone Hotspot mantle plume melted continental crust above it. The melted pockets of magma fed a series of volcanoes over the last 16 million years. Most of them are buried and hidden, but the Henry’s Fork Caldera is well exposed, and the Yellowstone Caldera is partially visible. The blue star is the approximate location of Teton Dam.
Image: https://www.nps.gov/features/yell/slidefile/graphics/diagrams/Images/15899.jpg
Image: https://www.nps.gov/features/yell/slidefile/graphics/diagrams/Images/15899.jpg
As dense magma from the hotspot accumulated in the crust, the extra weight caused the crust to sink. That crustal depression accumulated additional sediments and volcanic rocks, which caused more sinking. The rocks along the hotspot track in ESRP subsided about 2.8 miles compared to the surrounding rocks. The basalts in the ESRP weather into very fertile soils that sustain major agricultural production. Idaho potato growers harvest an average of 13.5 billion pounds of potatoes annually.
Basalt at the bottom of the Teton River Canyon is an erosional remnant of a lava flow that once filled the canyon to an elevation of about 5,005 feet. It is buried at shallow depths under recent alluvium in the river flood plain. In the dam foundation, the basalt is restricted to the left side (southeast) of the river channel section, where it has a maximum thickness of about 124 feet. It is separated from the underlying welded tuff by a deposit of alluvial material consisting of silt, sand, and gravel from 4 to 22 feet thick. The basalt is dense to moderately vesicular and contains closely spaced, randomly oriented joints and other fractures.
Basalt at the bottom of the Teton River Canyon is an erosional remnant of a lava flow that once filled the canyon to an elevation of about 5,005 feet. It is buried at shallow depths under recent alluvium in the river flood plain. In the dam foundation, the basalt is restricted to the left side (southeast) of the river channel section, where it has a maximum thickness of about 124 feet. It is separated from the underlying welded tuff by a deposit of alluvial material consisting of silt, sand, and gravel from 4 to 22 feet thick. The basalt is dense to moderately vesicular and contains closely spaced, randomly oriented joints and other fractures.
Left: Huckleberry Ridge Tuff has three ignimbrite (welded tuff) units which were separated by eruption pauses of weeks to decades. They formed during explosive eruptions that blasted ash high into the atmosphere. The ash fell back to the ground, blanketing the region around the volcano. If the ash was hotter than 600 degrees C (1,100 degrees F) when it landed, the particles would melt (weld) together.
According to the Yellowstone Volcano Observatory (YVO), recent research has found subtle variations in particle compositions and minerals from the start of the eruption, suggesting the magma was stored as four separate melt bodies. There is no evidence that these melt pockets mixed with each other, so there were likely several active vents, each erupting magma from different melt pockets, instead of a single central vent (YVO, 2019, Yellowstone’s Mushy Past, https://www.usgs.gov/observatories/yvo/news/yellowstones-mushy-past).
Image: National Park Service, undated, Pyroclastic Flows and Ignimbrites, and Pyroclastic Surges, https://www.nps.gov/articles/000/pyroclastic-flows-and-ignimbrites-and-pyroclastic-surges.htm
Right: Huckleberry Ridge Tuff at Mt. Everts in Yellowstone. The lower horizontal layers are ashfall deposits. The upper portion shows wind ripples in the fine ash.
Image: https://www.usgs.gov/media/images/huckleberry-ridge-tuff-fall-deposits-mount-everts-yellowstone
According to the Yellowstone Volcano Observatory (YVO), recent research has found subtle variations in particle compositions and minerals from the start of the eruption, suggesting the magma was stored as four separate melt bodies. There is no evidence that these melt pockets mixed with each other, so there were likely several active vents, each erupting magma from different melt pockets, instead of a single central vent (YVO, 2019, Yellowstone’s Mushy Past, https://www.usgs.gov/observatories/yvo/news/yellowstones-mushy-past).
Image: National Park Service, undated, Pyroclastic Flows and Ignimbrites, and Pyroclastic Surges, https://www.nps.gov/articles/000/pyroclastic-flows-and-ignimbrites-and-pyroclastic-surges.htm
Right: Huckleberry Ridge Tuff at Mt. Everts in Yellowstone. The lower horizontal layers are ashfall deposits. The upper portion shows wind ripples in the fine ash.
Image: https://www.usgs.gov/media/images/huckleberry-ridge-tuff-fall-deposits-mount-everts-yellowstone
The welded tuff (ignimbrite) on the northwest side of the canyon correlates with the Huckleberry Ridge Tuff, which erupted 2.1 million years ago from the Island Park Caldera. Island Park Caldera is the largest caldera on the Yellowstone Plateau. The Huckleberry Ridge eruption blew out 590 cubic miles (2,450 cubic km) of material. It was one of Yellowstone’s largest eruptions, with Huckleberry Ridge deposits extending as far as California and Texas. The volume of ejecta places it in the category of supervolcano eruptions.
Left: Extent of Island Park Caldera of the Yellowstone Volcanic System. The Huckleberry Ridge eruption blew out nearly 600 cubic miles of material. The Huckleberry Ridge volcano then collapsed in on itself forming the Island Park Caldera.
Image: https://commons.wikimedia.org/wiki/File:IPCaldera.jpg
Right: Comparison of eruption volumes. Volcanoes with eruption volumes exceeding 200 cubic miles of ejecta are considered super volcanoes. The large blue box above represents the relative volume of the Huckleberry Ridge super eruption.
Image: https://home.nps.gov/articles/000/-super-volcanoes.htm
Image: https://commons.wikimedia.org/wiki/File:IPCaldera.jpg
Right: Comparison of eruption volumes. Volcanoes with eruption volumes exceeding 200 cubic miles of ejecta are considered super volcanoes. The large blue box above represents the relative volume of the Huckleberry Ridge super eruption.
Image: https://home.nps.gov/articles/000/-super-volcanoes.htm
The welded tuff is light weight, has a porphyritic texture with coarse-grained feldspar phenocrysts in a fine-to-medium-grained tuff matrix. Holes drilled before the dam construction showed the contact between the welded ash-flow tuff and underlying sedimentary deposits was an erosion surface with moderate relief, suggesting an older stream valley existed in the same area before the Huckleberry Ridge tuff eruption.
Teton Dam E-W Diagrammatic cross section.
Image: https://damfailures.org/case-study/teton-dam-idaho-1976/.
Image: https://damfailures.org/case-study/teton-dam-idaho-1976/.
Lake and stream sediments that interfinger the volcanic rocks consist of a variety of sedimentary types described in exploratory drill hole logs as tuffaceous conglomerate, sandstone, tuff, lapilli tuff, ash, tuffaceous sediment, volcanic ash, sand and gravel, boulders, cobbles, and interlayered silt and gravel.
The rhyolitic welded tuff on the northwest (right) side of the dam was highly fractured and jointed, especially between 5,190 to 5,230 feet. The extreme fracturing is clearly displayed in this photo of the right abutment area before construction of the dam. Extensive voids in the tuff were found during excavation, including fissures as wide as 6 feet, that act as flow paths for water unless they are sealed during construction.
Image: Rodgers, J. David, undated, Retrospective on the Failure of Teton Dam near Rexburg, Idaho, https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Image: Rodgers, J. David, undated, Retrospective on the Failure of Teton Dam near Rexburg, Idaho, https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Joints are abundant in the rocks of the canyon. They are exposed prominently in the canyon walls and were visible in the drill cores obtained before construction. The joints are part of an extensive interconnecting, highly permeable system that transmits and stores groundwater in the area. During excavation of the dam foundation, large openings were found in the abutment trenches. One fissure was explored by a Bureau of Reclamation employee for about 100 ft both downstream and upstream of the dam axis. He said the cavity downstream as about 4 feet wide with blocks of rock as big as 4 or 5 feet wide on the floor. Upstream, the roof and floor of the cavity had stalactites and stalagmites up to 3/8-inch in diameter.
Attempts were made to fill the fissures with grout, but after pumping in double the amount of grout included in the budget, the work was stopped due to cost overruns. The fissures around 5,200 feet were still taking in grout at that time, so were not completely sealed.
Attempts were made to fill the fissures with grout, but after pumping in double the amount of grout included in the budget, the work was stopped due to cost overruns. The fissures around 5,200 feet were still taking in grout at that time, so were not completely sealed.
Teton Dam Construction
Teton River Canyon potential dam sites were evaluated by the Bureau of Reclamation in the 1930’s and 1940’s. Momentum on the project accelerated after drought in 1960-1961 was followed by flooding in 1962. The planned dam would help control flooding, store water for droughts, supplement irrigation of 112,000 acres of farmland, generate 16,000 Kw of hydroelectric power and provide recreation on the reservoir.
The Teton Dam project got congressional authorization in September 1964, but lack of funding and a questionable 14-page environmental impact statement delayed it. Construction of the dam was opposed by multiple environmental groups including Trout Unlimited, the Sierra Club, Idaho Environmental Council and the Natural Resources Defense Council. In 1971 the groups filed a lawsuit (Trout Unlimited v. Morton) that included concerns about the site geology, potential environmental impact, and destruction of excellent trout fishing. The suit was later dismissed.
Geologic and seismic concerns about the location prompted the Department of Interior to begin a review that delayed bidding for the construction contract. United States Geological Survey geologists voiced concerns about nearby fault zones and site permeability. The Idaho congressional delegation pressured the Department of the Interior to stop the review. The contract was awarded in late 1971 to a joint venture of two companies who bid just under $40 million to build the dam.
Construction began in February 1972 and was completed in 1975. The plans were for a 305-foot-high zoned-earth dam built at an elevation of 5,332 feet. The crest was planned to be 3,100 feet long and the width of the base would be 1,700 feet. The resulting reservoir would be 17 miles long.
The Teton Dam project got congressional authorization in September 1964, but lack of funding and a questionable 14-page environmental impact statement delayed it. Construction of the dam was opposed by multiple environmental groups including Trout Unlimited, the Sierra Club, Idaho Environmental Council and the Natural Resources Defense Council. In 1971 the groups filed a lawsuit (Trout Unlimited v. Morton) that included concerns about the site geology, potential environmental impact, and destruction of excellent trout fishing. The suit was later dismissed.
Geologic and seismic concerns about the location prompted the Department of Interior to begin a review that delayed bidding for the construction contract. United States Geological Survey geologists voiced concerns about nearby fault zones and site permeability. The Idaho congressional delegation pressured the Department of the Interior to stop the review. The contract was awarded in late 1971 to a joint venture of two companies who bid just under $40 million to build the dam.
Construction began in February 1972 and was completed in 1975. The plans were for a 305-foot-high zoned-earth dam built at an elevation of 5,332 feet. The crest was planned to be 3,100 feet long and the width of the base would be 1,700 feet. The resulting reservoir would be 17 miles long.
Left: Simplified cross-section of a zoned earthen or embankment dam. At Teton dam the impervious (impermeable) material was silty, compacted windblown loess from the surrounding plain. The pervious (permeable) portion was built of Teton River sand and gravel.
Image: https://elementaryengineeringlibrary.com/civil-engineering/soil-mechanics/earth-dam-introduction-types-and-calculation-of-seepage-through-it
Right: Teton Dam had windblown silty loess as the core material (lighter color) with permeable river sand and gravel (grey color), as the free draining, pervious portion. The materials were excavated from the surrounding plain and alluvial deposits.
Image: https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Image: https://elementaryengineeringlibrary.com/civil-engineering/soil-mechanics/earth-dam-introduction-types-and-calculation-of-seepage-through-it
Right: Teton Dam had windblown silty loess as the core material (lighter color) with permeable river sand and gravel (grey color), as the free draining, pervious portion. The materials were excavated from the surrounding plain and alluvial deposits.
Image: https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
A zoned-earth dam has distinct parts or zones of material, typically a shell of locally plentiful material with a watertight core. Modern zoned-earth embankments employ filter and drain zones to collect and remove seep water.
Left: Rock filled dump trucks were used to compact Zone 1 material (loess) next to the abutments. The right (northwest) abutment trench is visible in the background.
Image: https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Right: Foundation work during construction of Teton Dam.
Image: https://damfailures.org/case-study/teton-dam-idaho-1976/
Image: https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Right: Foundation work during construction of Teton Dam.
Image: https://damfailures.org/case-study/teton-dam-idaho-1976/
In May 1976 the completed dam was filling at 3-4 feet per day, three times the normal fill rate for dams. The rapid fill rate was higher than usual due to heavy spring snowmelt. The Bureau of Reclamation approved the higher rate. Shortly after 7:00 am on Saturday June 5th, workers noticed a couple small leaks low on the toe of the dam.
Image: Rodgers, J. David, undated, Retrospective on the Failure of Teton Dam near Rexburg, Idaho, https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Image: Rodgers, J. David, undated, Retrospective on the Failure of Teton Dam near Rexburg, Idaho, https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Teton Dam Failure
Early on the morning of Saturday June 5, 1976, workers noticed water flowing from the rock in the right abutment of the new dam as it was filling for the first time. The leak increased rapidly and shortly before 11:00 am the project engineer ordered workers to safety and called local sheriffs to order evacuations downstream. By 11:57 am the reservoir broke through releasing an 80-billion-gallon torrent of water.
Image 1: Rodgers, J. David, undated, Retrospective on the Failure of Teton Dam near Rexburg, Idaho https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Images 2-6: https://www.usbr.gov/pn/snakeriver/dams/uppersnake/teton/index.html
Images 2-6: https://www.usbr.gov/pn/snakeriver/dams/uppersnake/teton/index.html
At 11:57 Saturday June 5, 1976 the dam was breached, unleashing an 80-billion-gallon torrent of water at a rate over a million cubic feet per second.
Image: https://www.flickr.com/photos/waterarchives/5811736921/in/album-7215762689388519
Image: https://www.flickr.com/photos/waterarchives/5811736921/in/album-7215762689388519
The flood inundated 240 km2, flowing 93 miles along the Teton River to the American Falls Reservoir where the water was successfully retained. In places the flooded area was about 7 miles wide. The flood took three days to reach American Falls, so there was some time to prepare its old dam by releasing water before the flood arrived
Image: https://www.usbr.gov/pn/snakeriver/dams/uppersnake/teton/1976failure.pdf
Image: https://www.usbr.gov/pn/snakeriver/dams/uppersnake/teton/1976failure.pdf
American Falls Dam, built in 1927, had deteriorating concrete so its capacity had been restricted. To save it and dams further downstream, officials desperately opened flood gates, lowering reservoir levels in hope that they could absorb the coming flood when it arrived three days after Teton Dam broke. The old reservoir released more water than ever to receive more volume faster than ever and did not fail. From June 1 to June 6, the normal reservoir inflows averaged 14,300 cubic feet per second per day. On June 7 & 8, that volume peaked at 41,000 cubic feet per second (Palmer, Zeb, 2006, Teton Dam Failure - Actual Data for American Falls, https://archive.ph/20130210015927/http:/www.zebpalmer.com/oldblogarchive/teton-dam-failure-actual-data-for-american-falls/).
Left: Map of canyon and area at canyon mouth (flooded area outlined by stipple pattern) showing dimensions (in centimeters) of boulders transported during the flood. Symbol at upper right refers to the following lithologies: b, basalt; t, welded tuff; c, concrete. Minimum distance of transport in meters shown in parenthesis. Areas where erosion of bedrock occurred are hachured. Q gravel alluvium; Qb basalt; Qw welded tuff.
Image: Scott, W. E., 1977, Geologic Effects of Flooding from Teton Dam Failure, Southeastern Idaho, U.S. Geological Survey, Open-File Report 77-507, Fig.2, p. 6 at https://pubs.usgs.gov/of/1977/0507/report.pdf
Right: The rapid filling and catastrophic draining of the reservoir triggered more than 200 landslides upstream in the river canyon that held the escaped reservoir.
Image: https://www.flickr.com/photos/byui_library/4379614037/in/album-72157623364635347
Image: Scott, W. E., 1977, Geologic Effects of Flooding from Teton Dam Failure, Southeastern Idaho, U.S. Geological Survey, Open-File Report 77-507, Fig.2, p. 6 at https://pubs.usgs.gov/of/1977/0507/report.pdf
Right: The rapid filling and catastrophic draining of the reservoir triggered more than 200 landslides upstream in the river canyon that held the escaped reservoir.
Image: https://www.flickr.com/photos/byui_library/4379614037/in/album-72157623364635347
Aftermath of Teton Dam Failure
Over 300 members of the Idaho National Guard 116th Engineering Battalion assisted cleanup with heavy equipment and water purification units. The Idaho National Guard also mobilized 12 helicopters to remove large debris (cars and farm equipment) and animal carcasses.
Gas and power utility companies worked around the clock to restore service to the area. Utah Power restored power to 95% of the distribution and transmission lines.
The Bureau of Reclamation worked to clear irrigation canals that supplied water to 427,000 acres of cropland. The flood stripped rich topsoil off 110,000 acres of fertile farmland, drowned crops and left behind thick blankets of sediment. Potato fields were the hardest hit due to their pronounced furrows and mounds causing turbulent water flow. Flat wheat and alfalfa fields fared better
Tens of thousands of volunteers came to help with the clean-up. Many were friends and family of the flood victims, members of affiliated LDS churches (Church of Latter-Day Saints) in Idaho, Utah, Montana and Wyoming, and members of other religious groups from as far away as Canada. In two months after the disaster, volunteers provided over a million hours of work to cleanup and restoration. Near the end of the summer, those still living in Ricks College dormitories were relocated to Housing and Urban Development trailers so the college could resume classes in the fall.
The Bureau of Reclamation paid nearly half a billion dollars to compensate for flood losses. In September 1976, President Gerald Ford signed the Teton Disaster Bill, which authorized compensation for lost property.
Gas and power utility companies worked around the clock to restore service to the area. Utah Power restored power to 95% of the distribution and transmission lines.
The Bureau of Reclamation worked to clear irrigation canals that supplied water to 427,000 acres of cropland. The flood stripped rich topsoil off 110,000 acres of fertile farmland, drowned crops and left behind thick blankets of sediment. Potato fields were the hardest hit due to their pronounced furrows and mounds causing turbulent water flow. Flat wheat and alfalfa fields fared better
Tens of thousands of volunteers came to help with the clean-up. Many were friends and family of the flood victims, members of affiliated LDS churches (Church of Latter-Day Saints) in Idaho, Utah, Montana and Wyoming, and members of other religious groups from as far away as Canada. In two months after the disaster, volunteers provided over a million hours of work to cleanup and restoration. Near the end of the summer, those still living in Ricks College dormitories were relocated to Housing and Urban Development trailers so the college could resume classes in the fall.
The Bureau of Reclamation paid nearly half a billion dollars to compensate for flood losses. In September 1976, President Gerald Ford signed the Teton Disaster Bill, which authorized compensation for lost property.
Left Image: https://www.flickr.com/photos/waterarchives/5811899677
Right Image: https://c2.staticflickr.com/6/5110/5812450404_8dfb54a083_b.jp
Right Image: https://c2.staticflickr.com/6/5110/5812450404_8dfb54a083_b.jp
Left and Right: Rexburg, ID was flooded as deep as 8 feet, causing extensive damage
Left Image: https://www.flickr.com/photos/waterarchives/5874587893/in/album-72157626893885194
Right Image: https://www.flickr.com/photos/waterarchives/5874594879/in/album-7215762689388519
Left Image: https://www.flickr.com/photos/waterarchives/5874587893/in/album-72157626893885194
Right Image: https://www.flickr.com/photos/waterarchives/5874594879/in/album-7215762689388519
Left: Inundated homes in Wilford, ID. Of the 154 homes in Wilford, 110 were destroyed and 20 more were heavily damaged.
Image: https://www.flickr.com/photos/waterarchives/5811893505/in/album-72157626893885194
Right: Sugar City, ID, aerial view of floodwaters moving down the Valley.
Image: https://www.flickr.com/photos/waterarchives/5875143854/in/album-7215762689388519
Image: https://www.flickr.com/photos/waterarchives/5811893505/in/album-72157626893885194
Right: Sugar City, ID, aerial view of floodwaters moving down the Valley.
Image: https://www.flickr.com/photos/waterarchives/5875143854/in/album-7215762689388519
Left: Meyers Feedlot lost 1,200 of the 13,000 cattle killed by the flood.
Image: https://www.flickr.com/photos/waterarchives/5812456710/in/album-72157626893885194
Right: Stranded Holstein steer in Rexburg,ID.
Image: https://www.flickr.com/photos/waterarchives/5875621716/in/album-72157626893885194
Image: https://www.flickr.com/photos/waterarchives/5812456710/in/album-72157626893885194
Right: Stranded Holstein steer in Rexburg,ID.
Image: https://www.flickr.com/photos/waterarchives/5875621716/in/album-72157626893885194
Left Image: https://www.flickr.com/photos/waterarchives/5811911479/in/album-72157626893885194
Right Image: https://www.flickr.com/photos/byui_library/4379587277/in/album-72157623364635347
Right Image: https://www.flickr.com/photos/byui_library/4379587277/in/album-72157623364635347
Flood survivors downstream from the dam had strong opinions about blame for the disaster.
Left Image: https://www.flickr.com/photos/byui_library/4380346808/in/album-72157623364635347
Right Image: https://www.flickr.com/photos/waterarchives/5899201999/in/album-7215762679126866
Left Image: https://www.flickr.com/photos/byui_library/4380346808/in/album-72157623364635347
Right Image: https://www.flickr.com/photos/waterarchives/5899201999/in/album-7215762679126866
Left: Union Pacific Railroad lost 32 miles of tracks
Image: https://www.flickr.com/photos/byui_library/4380346808/in/album-72157623364635347
Right: Nearly 80 percent of the valley’s 700 miles of county roads washed away, and the flood destroyed seven bridges.
Image: https://www.flickr.com/photos/waterarchives/5901679411/in/album-7215762679126866
Image: https://www.flickr.com/photos/byui_library/4380346808/in/album-72157623364635347
Right: Nearly 80 percent of the valley’s 700 miles of county roads washed away, and the flood destroyed seven bridges.
Image: https://www.flickr.com/photos/waterarchives/5901679411/in/album-7215762679126866
Left: 50 million cubic meters of sediment and debris were deposited by the flood, requiring massive cleanups.
Left Image: https://www.flickr.com/photos/waterarchives/5902513776/in/album-72157626791268665
Right: The Department of Housing and Urban Development flew in hundreds of house trailers starting June 17th as temporary housing for 25,000 homeless flood victims. Others stayed in dormitories at a local college or with family.
Image: https://www.flickr.com/photos/byui_library/4380370940/in/album-7215762336463534
Left Image: https://www.flickr.com/photos/waterarchives/5902513776/in/album-72157626791268665
Right: The Department of Housing and Urban Development flew in hundreds of house trailers starting June 17th as temporary housing for 25,000 homeless flood victims. Others stayed in dormitories at a local college or with family.
Image: https://www.flickr.com/photos/byui_library/4380370940/in/album-7215762336463534
Outcomes of Teton Dam Failure
The Department of the Interior Teton Dam Failure Review Group was organized June 8, 1976 to investigate the disaster. In addition, the Independent Panel to Review the Cause of the Teton Dam Failure was impaneled and tasked by the Secretary of the Interior and the Idaho Governor to investigate the dam failure. There were also Congressional hearings. The consensus was that the dam was poorly designed and failed due to internal erosion. The Teton Dam Failure Review Group said an independent review of the BOR design might have caught flaws before construction.
The Bureau of Reclamation Division of Dam Safety and the Safety Evaluation of Existing Dams Program (SEED) was created in the late 1970s to prevent future dam disasters. Congress passed the Reclamation Safety of Dams Act in 1978. It expired in 2011 but then Congress reauthorized it in 2014. Currently there are over 92,000 dams in the United States, with an average age of 62 years. Many are approaching the end of their design life.
The Bureau of Reclamation Division of Dam Safety and the Safety Evaluation of Existing Dams Program (SEED) was created in the late 1970s to prevent future dam disasters. Congress passed the Reclamation Safety of Dams Act in 1978. It expired in 2011 but then Congress reauthorized it in 2014. Currently there are over 92,000 dams in the United States, with an average age of 62 years. Many are approaching the end of their design life.
Dam hazards: Red = High hazard risk of failure with probable loss of human life and economic impact; Orange = Significant hazard with possible loss of human life and infrastructure damage; Blue = Low hazard with low risk of lost lives or economic loss; Purple = Unknown hazard potential.
Image: https://storymaps.arcgis.com/stories/8ccc7c66ab03442cba96751f0010d4d1
Image: https://storymaps.arcgis.com/stories/8ccc7c66ab03442cba96751f0010d4d1
Things To Do Near Teton Dam
- Museum of Rexburg, 51 Center Street, Rexburg, ID has an exhibit on the Teton Flood. It includes photos, artifacts from the flood and a model of Teton Dam. The museum is in the Rexburg Tabernacle, which is closed for major renovations (at the time of this writing in 2024). In the future, check to see if it has reopened.
- Island Park Caldera, 54 miles (https://www.usgs.gov/observatories/yvo/news/ashton-island-park-21-million-years-volcanic-history-30-minutes/)
- Rexburg Rapids Waterpark, 50 W 2nd N, Rexburg, ID. This water park is open seasonally, weather permitting. Call ahead to see if they are open. They have water slides, a lazy river, lap pool, rock wall and splash pads.
References and Links
Boise Power, undated, Remembering the Teton Dam. This video is 20 minutes long; with film of the dam collapse and a celebration of the heroic restoration of power to the community. https://powerboise.com/remembering-the-teton-dam/
Deseret News, June 7, 1976, Salt Lake City. Multipage articles on Teton Dam
https://news.google.com/newspapers?id=DFtTAAAAIBAJ&sjid=SYUDAAAAIBAJ&pg=6350%2C1394463
East Idaho News, 2020, The Teton Dam broke 44 years ago today. https://www.eastidahonews.com/2020/06/the-teton-dam-broke-44-years-ago-today-this-man-was-sitting-on-it-when-it-happened/ This is an interview with a dam worker who tried to plug the dam hole with a bulldozer; it lasts 6 minutes, 18 seconds.
History Channel video has animated segments showing how the dam failed and video of the collapse.
https://play.history.com/shows/modern-marvels/videos/teton-dam-disaster?playlist_slug=modern-marvels-season-15-curated-list
Idaho Bureau of Emergency Management, undated, 1976 Teton Dam Collapse, https://ioem.idaho.gov/news/a-history-of-idaho-disasters/dam-collapse/
Independent Panel to Review Cause of Teton Dam Failure, 1976, Report to U.S. Department of the Interior and State of Idaho on Failure of Teton Dam, https://archive.org/details/reporttousdepart00inde/page/n3/mode/2up
Palmer, Zeb, 2006, Teton Dam Failure- Actual Data for American Falls, https://archive.ph/20130210015927/http:/www.zebpalmer.com/oldblogarchive/teton-dam-failure-actual-data-for-american-falls/
The Reclamation Safety of Dams Act of 1978. https://www.usbr.gov/ssle/damsafety/documents/SOD-Act-114-113-Dec2015.pdf
Summarizes some of the engineering aspects of the dam.
Rodgers, J. David, undated, Retrospective on the Failure of Teton Dam near Rexburg, Idaho, https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf
Deseret News, June 7, 1976, Salt Lake City. Multipage articles on Teton Dam
https://news.google.com/newspapers?id=DFtTAAAAIBAJ&sjid=SYUDAAAAIBAJ&pg=6350%2C1394463
East Idaho News, 2020, The Teton Dam broke 44 years ago today. https://www.eastidahonews.com/2020/06/the-teton-dam-broke-44-years-ago-today-this-man-was-sitting-on-it-when-it-happened/ This is an interview with a dam worker who tried to plug the dam hole with a bulldozer; it lasts 6 minutes, 18 seconds.
History Channel video has animated segments showing how the dam failed and video of the collapse.
https://play.history.com/shows/modern-marvels/videos/teton-dam-disaster?playlist_slug=modern-marvels-season-15-curated-list
Idaho Bureau of Emergency Management, undated, 1976 Teton Dam Collapse, https://ioem.idaho.gov/news/a-history-of-idaho-disasters/dam-collapse/
Independent Panel to Review Cause of Teton Dam Failure, 1976, Report to U.S. Department of the Interior and State of Idaho on Failure of Teton Dam, https://archive.org/details/reporttousdepart00inde/page/n3/mode/2up
Palmer, Zeb, 2006, Teton Dam Failure- Actual Data for American Falls, https://archive.ph/20130210015927/http:/www.zebpalmer.com/oldblogarchive/teton-dam-failure-actual-data-for-american-falls/
The Reclamation Safety of Dams Act of 1978. https://www.usbr.gov/ssle/damsafety/documents/SOD-Act-114-113-Dec2015.pdf
Summarizes some of the engineering aspects of the dam.
Rodgers, J. David, undated, Retrospective on the Failure of Teton Dam near Rexburg, Idaho, https://web.mst.edu/~rogersda/teton_dam/Retrospective%20on%20Teton%20Dam%20Failure.pdf

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