Egypt’s Aswan High Dam is a rock-and-clay embankment dam across the Nile at Aswan, about 7 km upstream of the older Aswan Low Dam in the far south of the country. It stands 111 m (364 ft) high and runs 3,830 m across the valley, and it was built between 9 January 1960 and 21 July 1970 with Soviet loans and a Soviet design. Behind it lies Lake Nasser, a reservoir of about 132 km³ that stretches roughly 480–500 km south into Sudan. Twelve generators give it 2,100 MW of capacity. The dam matters because Egyptian farming depends entirely on irrigation: it ended the Nile’s annual flood, turned an unpredictable river into stored water that can be released over several years, and for a time supplied about half of the country’s electricity.
1011–1946: From Ibn al-Haytham to the Nearly Overtopped Low Dam
The first recorded plan to dam the Nile near Aswan came from the Arab polymath Ibn al-Haytham. The Fatimid caliph al-Hakim bi-Amr Allah summoned him to Egypt to regulate the flood. Judging the scheme impossible and fearing the caliph, he feigned madness and spent 1011–1021 under house arrest, writing his Book of Optics.
Nearly nine centuries passed before anyone built a barrier. British engineers began the Aswan Low Dam in 1898 and opened it on 10 December 1902. Sir William Willcocks designed it, Sir Benjamin Baker also worked on it, and the main contractor was Sir John Aird’s firm, John Aird & Co. Its reservoir was too small to stop floods and droughts. In 1946 the Low Dam came close to being overtopped, which showed how little margin it had left.
Before 1952 the favoured solution was the British hydrologist Harold Edwin Hurst’s Nile Valley Plan. It proposed storing the river’s water upstream in Sudan and Ethiopia, where less of it would evaporate. The government of King Farouk showed no interest in a rival idea from Adrian Daninos, a Greek-Egyptian engineer who wanted one giant reservoir inside Egypt.
1952–1956: Daninos’s Plan, the Dulles Withdrawal and the Suez Canal
The 1952 overthrow of the monarchy by the Free Officers Movement, which included Gamal Abdel Nasser, changed everything. The new rulers believed the Nile’s water had to be stored on Egyptian soil for political reasons, and they accepted Daninos’s plan within two months.
Cold War rivalry soon got in the way. In September 1955 Nasser announced an arms deal with the Soviet bloc, with Czechoslovakia acting as middleman. US Secretary of State John Foster Dulles at first tried to win him back. In December 1955 the United States and Britain pledged $56 million and $14 million toward the dam, alongside a larger loan offer of $270 million. Dulles was angered by Egypt’s recognition of the People’s Republic of China and irritated by Nasser’s neutrality. Britain cited the arms deal as a reason to drop its pledge. In June 1956 Moscow offered Egypt $1.12 billion at 2% interest. On 19 July the US State Department said that American support was “not feasible in present circumstances.”
Nasser answered a week later. On 26 July 1956 he nationalised the Suez Canal, planning to use its tolls to pay for the dam. That autumn Britain, France and Israel seized the canal and Sinai, then withdrew under pressure from Washington and Moscow at the United Nations.
1958–1964: Soviet Credits, Malyshev’s Design and the First Stage
In 1958 the Soviet Union committed to the project. A first loan of $100 million paid for the cofferdams that diverted the Nile. A second loan of $225 million in 1960 covered the main dam and its power plant, and about $100 million more later went to land reclamation. The roughly $425 million in credits covered only foreign-exchange costs, such as Soviet equipment and the salaries of the Soviet engineers who supervised the work. Most were lent for 12 years at 2.5% interest. Egypt paid all domestic costs itself.
The final design came from Nikolai Aleksandrovich Malyshev of the Hydroproject Institute in Moscow, working with Egyptian engineers. It included a very deep grout curtain beneath the base, a feature that was still relatively new in the 1960s. Egyptian companies did the building on contract to the High Dam Authority. The leading contractor was Arab Contractors, the firm of Osman Ahmed Osman, who had underbid his only competitor by half. About 25,000 Egyptian engineers and workers took part. Work officially began on 9 January 1960. The first construction stage was finished in 1964, and the reservoir began to fill that year.
The finished dam contains about 43 million m³ of rock, sand and clay. It is 980 m wide at the base and 40 m wide at the crest. When it was completed it was the tallest earthen dam in the world, surpassing the Chatuge Dam in the United States.
1960–1968: Nubia Under Water and the Temples That Moved
The rising reservoir drowned much of Lower Nubia. Between 100,000 and 120,000 people were resettled in Egypt and Sudan. In Sudan, 50,000 to 70,000 Nubians left the old town of Wadi Halfa and nearby villages. Some moved to New Wadi Halfa on the new lakeshore. Others went about 700 km south to the Butana plain near Khashm el-Girba on the Atbara River. In Egypt, most of the 50,000 displaced Nubians were rehoused near Kom Ombo, about 45 km downstream of Aswan, in 47 village units known as “New Nubia”. Egypt did not begin compensating Nubians for their lost homes until 2019–20.
Archaeologists had warned in the 1950s that the lake would swallow Nubia’s monuments. A UNESCO international campaign, launched in 1959, moved 22 monuments and architectural complexes to higher ground. The largest job was Abu Simbel. Ramesses II’s rock-cut temples would otherwise have stood under as much as 60 m of water. They were cut from the cliff and rebuilt inside an artificial hill, and the move was finished in 1968. Philae, Kalabsha and Amada were moved too. Several temples were given to countries that helped: Debod to Madrid, Dendur to the Metropolitan Museum of Art in New York, Taffeh to the Rijksmuseum van Oudheden in Leiden, and Ellesyia to the Museo Egizio in Turin. The fort at Buhen and the cemetery of Fadrus could not be saved, and both now lie under the lake. The full story of the Abu Simbel rescue is told in our guide to Abu Simbel.
1967–1976: Turbines, 21 July 1970 and a Full Lake Nasser
Power generation started in 1967, and all the power facilities were finished ahead of schedule. Twelve turbines rated at 175 MW each gave an installed capacity of 2,100 MW, more than double Egypt’s entire national capacity in 1960. In 1968 Israeli commandos damaged a main transformer station, which was later repaired. When the plant first reached peak output in 1970, it produced around half of Egypt’s electricity and brought power to most Egyptian villages for the first time. At completion it was the largest power station in Africa.
The dam was declared complete on 21 July 1970. Nasser, whose name the reservoir carries, died on 28 September that year, and his successor Anwar Sadat inaugurated the dam and lake in 1971. The reservoir kept rising until it reached capacity in 1976. At full supply it covers about 5,250 km² and holds about 132 km³. Roughly 83% of the lake lies in Egypt. Sudan calls its smaller share Lake Nubia.
On one estimate the dam repaid its E£450 million cost within about two years. A declassified 1971 CIA report added a caveat: because of limited water and competing seasonal demands from irrigation, the plant could sustain only about 5 billion kWh a year, half of its theoretical 10 billion kWh. By 1998 the dam’s share of Egypt’s electricity had fallen to about 15% as other power stations were built.
1972–1990s: Droughts Averted, Silt Lost and a Salinity Fight
The reservoir carried Egypt through the droughts of 1972–73 and 1983–87, which devastated East and West Africa, and it held back the floods of 1973 and 1988. On average the dam releases about 55 km³ of water a year, and around 46 km³ of that goes into irrigation canals. About 840,000 hectares of desert and former flood basins were reclaimed, which raised Egypt’s irrigated area by about a third. Roughly 420,000 hectares in Upper Egypt switched from a single flood-season crop to year-round irrigation. Water that used to reach the Mediterranean unused, about 32 km³ a year, was now kept, although Lake Nasser loses somewhere between 10 and 16 km³ a year to evaporation.
The costs also showed up in these years. The dam traps the silt the Nile once carried to the sea, and the Nile Delta coastline has eroded since. A 1971 CIA report found that Egypt’s Mediterranean fish catch had fallen from 35,000–40,000 tonnes a year to 20,000 tonnes or less, largely because the sardines had disappeared. A new fishery on Lake Nasser was landing about 35,000 tonnes a year by the mid-1990s. Without the yearly flood to flush the soil, groundwater stayed high, causing waterlogging and salt build-up. Egypt answered with subsurface drainage. By 2003 more than 2 million hectares had drains, built with about $3.1 billion invested between 1973 and 2002, including 11 large projects supported by the World Bank and other donors.
1998–2026: The Toshka Overflow and a New Dam on the Blue Nile
In 1998 heavy floods in the Ethiopian Highlands tested the reservoir. In September Lake Nasser reached 183 m above sea level for the first time. Surplus water ran west through the Toshka spillway channel into a desert depression, receiving between 32 and 98 million m³ a day in September and October. New lakes appeared from November 1998 and eventually covered about 1,300 km², then shrank until the basins were almost dry by 2017–18. They refilled after heavy rains in Sudan from 2019, and the 2020 floods pushed Lake Nasser to its highest level on record.
The dam’s biggest modern question lies upstream. Ethiopia built the Grand Ethiopian Renaissance Dam on the Blue Nile between 2011 and 2025. With 5.15 GW of capacity it is now Africa’s largest hydroelectric plant, and its reservoir was filled in stages from July 2020. About 59% of the water that reaches Egypt comes down the Blue Nile from the Ethiopian Highlands, so Egypt’s water supply now depends partly on how a foreign dam is run, which is explained further in our Blue Nile river guide. A 2024 study by Nicol-André Berdellé warned that silt building up in Lake Nasser makes an overflow of the High Dam more likely each year, and urged lower operating levels and a deeper Toshka spillway. To see how the dam, the lake and the Nile Valley fit into the rest of the country, read our map guide to Egypt’s geography.