48 Fun Facts About Dams

Which type of dam relies on its own sheer weight to hold back the water?

Gravity dam: it is proportioned so that its own weight alone resists the water's push to slide it or tip it over, which is why these dams are such broad, heavy blocks of concrete or masonry.

An arch dam is curved in which direction?

Upstream, into the reservoir: the water presses on the outside of the curve and squeezes the arch into the gorge walls, keeping its joints closed, so a thin shell can do the work of a massive block.

Under what name was Hoover Dam commonly known from 1933 until Congress settled the matter in 1947?

Boulder Dam: after Hoover left office the Interior Department avoided his name, allegedly because the new Secretary disliked him, until a 1947 resolution signed by Truman restored it.

The Sadd el-Kafara, the oldest large dam known, was built around 2600 BCE by which civilisation?

The ancient Egyptians: they raised the 14-metre embankment across a ravine to hold back rare, violent floods, and one of those floods is thought to have destroyed it.

The 305 m concrete arch that became the world's tallest dam in the 2010s stands in which country?

China: Jinping-I spans the Yalong River in Sichuan, and the filling of its reservoir from 2012 was blamed by some for setting off hundreds of minor earthquakes nearby.

Nurek Dam, the world's tallest when finished in 1980, is in which former Soviet republic?

Completed in 1980 on the Vakhsh River, it held the overall height record until Jinping-I overtook it in 2013.

The 285-metre Grande Dixence Dam, once the tallest in the world, stands in which country?

Switzerland: the lake behind the wall fills each summer with meltwater from the glaciers of the Alps around it.

Lake Volta, one of the world's largest man-made lakes, lies entirely in which country?

Ghana: the lake covers about 3.6 percent of the country, and filling it behind the Akosombo Dam in the 1960s drowned hundreds of villages and displaced about 80,000 people.

Which Zambezi reservoir is the world's largest man-made body of water by volume?

Lake Kariba: it holds about 180 cubic kilometres, and as it filled a rescue known as Operation Noah moved thousands of stranded animals to safety.

The Itaipu Dam on the Paraná River is a joint project of which two countries?

Brazil and Paraguay: the neighbours' grids run at different frequencies, so ten of the twenty generators turn out 50 Hz power for Paraguay and the other ten 60 Hz for Brazil.

The reservoir of the Itaipu Dam drowned which waterfall, perhaps the greatest on Earth by volume of water?

Guaíra Falls: the roar of its cataracts carried for some 30 kilometres, until the rising reservoir swallowed them in 1982.

Grand Coulee Dam, the largest hydroelectric station in the United States, is in which state?

Washington: designed to water the desert, the dam spent the Second World War feeding the Northwest's aircraft factories and shipyards, plus a secret plutonium works.

Which folk singer wrote 26 songs in a month in 1941, including 'Roll On, Columbia', while promoting the Columbia dams?

Woody Guthrie: the Bonneville Power Administration hired him for a month to sell the public on its dams, and 'Roll On, Columbia', set to the tune of 'Goodnight, Irene', was later adopted as an official state folk song.

The Aswan High Dam, built between 1960 and 1970, was developed with the help of which country?

The Soviet Union: after the United States and Britain pulled their funding offer in 1956, Nasser seized the Suez Canal to pay for the dam, and Moscow stepped in with the loans.

Which was the most famous of the monuments moved clear of the rising Lake Nasser under UNESCO?

The Abu Simbel temples: between 1963 and 1968 Ramesses II's rock-cut temples were cut apart and rebuilt, block by block, on a man-made hill more than 60 metres above the old site.

The Grand Ethiopian Renaissance Dam, Africa's largest hydroelectric plant, sits on which river?

The Blue Nile: Ethiopians helped pay for the $5 billion dam by buying bonds and sending gifts, while Egypt downstream opposed it from the 2011 start to the 2025 opening.

Which dynasty built the Kallanai on the Kaveri River some 2,000 years ago, a stone dam still in use?

The Chola: King Karikala's stone dam still diverts the Kaveri across its delta, the rice bowl of Tamil Nadu, and the British engineers of the 1800s added regulators to it.

The great dam of Marib, which watered the capital of the ancient kingdom of Sheba, is in which modern country?

Yemen: the dam kept the desert around Marib green for more than a thousand years, and a bursting of it is recalled in the Quran as a punishment on the Sabaeans.

The tallest dam the Romans ever built, at Subiaco near Rome, held a pleasure lake for which emperor's villa?

Nero: his roughly 40-metre masonry wall was the highest dam the Romans ever raised, and it stood for more than twelve centuries before giving way in 1305.

Jawaharlal Nehru called which Indian dam a 'New Temple of Resurgent India'?

Bhakra Dam: speaking at the site on the Sutlej, Nehru cast India's new dams and power plants as the temples of a modern nation, and he came back in 1963 to dedicate the finished wall.

In 2017, damaged spillways at which California dam forced more than 180,000 people to flee?

Oroville Dam: the 770-foot earth wall on the Feather River was never itself at risk, but its emergency spillway came close to caving in, which officials feared would send a wall of water downstream.

Glen Canyon Dam forms which reservoir, named for the Civil War veteran who led an 1869 boat expedition through the Grand Canyon?

Lake Powell: John Wesley Powell had lost an arm at Shiloh, yet in 1869 he led four small boats down the Green and Colorado rivers and came out of the Grand Canyon some three months later.

Margaret Bourke-White's photo of Montana's Fort Peck Dam was the first cover of which magazine, in 1936?

Life: its editors had sent her for construction pictures, and wrote that they were surprised when she also brought back a human document of frontier life in the towns around the dam.

Tarbela, a giant dam born of a 1960 water-sharing treaty between India and Pakistan, holds back which river?

The Indus: the treaty handed India the three eastern rivers of the basin, so Pakistan built Tarbela to catch the summer floods of its main river and release them through the dry months.

A researcher found the world's longest beaver dam in 2007 while browsing which online service?

Google Earth: Jean Thie spotted the dam on satellite views of Wood Buffalo National Park, far from any road or trail, and park rangers later confirmed it from a helicopter.

Water pours down the 'Glory Hole' at California's Monticello Dam only when what happens?

The lake overfills: once Lake Berryessa rises past the funnel's rim, water drops straight down it and out through a pipe below the dam, which in 2017 happened for the first time in over a decade.

A stuntman's bungee jump off the towering Contra Dam in the Alps opens which James Bond film?

GoldenEye: Wayne Michaels made the drop of more than 700 feet for real, then a record for a bungee jump from a fixed structure, and a 2002 poll of film fans voted it the best movie stunt ever.

Operation Chastise, the 1943 'Dambusters' raid, breached which two German dams?

Möhne and Eder: the Sorpe was hit but held. The raid cost 53 of its 133 airmen, and more than half of the people drowned in the floods were foreign prisoners and forced labourers held in camps below the dams.

Who designed the bouncing bomb used against the German dams in 1943?

Barnes Wallis: his bomb skipped across the reservoir like a skimming stone, clearing the torpedo nets strung in front of the wall, then sank against it before exploding.

The failure of the South Fork Dam on 31 May 1889 caused which American disaster?

The Johnstown Flood: the dam's owners, a private club of Pittsburgh industrialists, had lowered its crest for a carriage road and screened the spillway to keep their game fish in, and the screens clogged with debris.

The 1928 St. Francis Dam collapse, which killed more than 400 people, ended which Los Angeles water chief's career?

William Mulholland: he had inspected the leaking dam that same day and judged it sound, and it broke just before midnight. At the inquest he said the only ones he envied were the dead.

What caused the 1963 Vajont Dam disaster in Italy?

A landslide sent a wave over the dam: a mountainside slid into the reservoir, and the wave that cleared the crest flattened the town of Longarone, killing about 2,000 people. The dam itself was left almost undamaged.

What set off the 1975 Banqiao Dam collapse in Henan?

A typhoon: Nina stalled over Henan and poured record rain onto an earthen dam so trusted it was nicknamed the 'Iron Dam'. It gave way in the night, and 61 other dams failed in the same storm.

The Teton Dam in Idaho failed catastrophically in June 1976 at what stage of its life?

While filling for the first time: a leak appeared that morning in the brand-new earth dam, and bulldozer crews tried in vain to plug it. By noon the wall had torn open, sending the new reservoir down the valley.

The Malpasset Dam, which burst in 1959, stood above which French Riviera town, founded by Julius Caesar as Forum Julii?

Fréjus: after days of heavy rain the thin concrete arch tore loose along a fault beneath it that nobody had found, and the wave that reached the town killed more than 400 people.

What failed at Russia's Sayano-Shushenskaya Dam in 2009, flooding its power hall and killing 75 people?

A turbine: unit 2 had been shaking for weeks, and when its worn holding-down bolts gave way the water blew the huge machine out of its seat. The plant's entire 6,400 MW output was lost.

Iraq's Mosul Dam is considered unusually dangerous because it was built on what kind of foundation?

Karst rock that dissolves: the gypsum beneath the dam slowly dissolves in the seeping water, so crews have kept pumping cement grout into the foundation ever since the reservoir filled in the 1980s.

Trouble at Venezuela's giant Guri Dam on 7 March 2019 led to what?

A nationwide blackout: the plant supplies most of Venezuela's electricity, so when it dropped out at the evening rush hour the Caracas metro stopped, phones went dead and most of the country's states lost power.

Which river on the California–Oregon border was freed in 2024 by the largest dam removal in history?

The Klamath: four hydropower dams came out, and soon after the last one went biologists found a Chinook salmon in Oregon's part of the basin, the first seen there in more than a century.

The Franklin Dam, stopped in 1983 after a High Court battle, was planned for which Australian state?

Tasmania: Bob Hawke won the 1983 federal election promising to stop the dam, his new government banned it, and the High Court upheld the ban by four votes to three.

Which Nordic country gets around nine-tenths of its electricity from hydropower?

Norway: its mountain reservoirs hold about half of all the hydropower storage in Europe, so the country can act as a giant battery for its neighbours.

Hoover Dam straddles the border between which two US states?

Nevada and Arizona: the state line crosses the dam, so clocks on its intake towers show Nevada time and Arizona time, because the two states sit in different time zones.

The primary reason the Akosombo Dam was built was to supply electricity to which industry?

Aluminium smelting: the smelter the dam was built to feed was American-owned, and its deal let it buy the electricity at rates below the market.

Ships cross Gatun Lake, a vast reservoir held back by a dam, while passing through which waterway?

The Panama Canal: each ship that passes through the locks flushes millions of litres of the lake's fresh water out to sea, so when drought shrank the lake in 2023 the canal had to cut its daily crossings.

The Aswan High Dam is built across which river?

The Nile: the dam ended the yearly flood and now traps the river's silt in its reservoir, so fields downstream no longer get a fresh layer of soil and the delta's coast is wearing away.

The Three Gorges Dam, the world's largest power station, spans which river?

The Yangtze: the reservoir drowned whole cities and towns along the gorges, and more than a million people had to be moved out of its way.

A dam built to hold back the waste left over from mining operations is called what kind of dam?

A tailings dam: unlike a water dam it keeps being raised as the mine produces more waste. When one at Brumadinho gave way in 2019, the sludge buried the mine's own canteen at lunchtime and killed 270 people.

The English word 'dam' traces back through Middle English to which language family?

Germanic: it probably reached English from Middle Dutch or Low German, and Dutch place names still carry it, since Amsterdam grew up around a dam on the river Amstel.