The ten largest human-made reservoirs ranked by nominal (total) volume, from Lake Kariba's 180.6 km³ on the Zambezi to Russia's Zeya Reservoir at 68.4 km³.
Lake Kariba on the Zambezi is the world's largest reservoir by volume, with a nominal capacity of 180.6 km³. The Bratsk Reservoir in Russia is second at 169 km³ and Lake Volta in Ghana third at 150 km³. The ranking uses nominal (total) volume, mainly from the Chao et al. (2008) global reservoir database, as of October 2026.
Reservoirs are lakes created or enlarged by damming a river to store water for drinking, irrigation, hydroelectric power and flood control. The largest hold more water than many natural lakes, and the top six each store more than 100 cubic kilometres. This list ranks the world's largest reservoirs by nominal volume, meaning total capacity at the maximum water level, in cubic kilometres. Natural lakes that have only been raised by a minor dam are excluded. Only reservoirs created by major dam construction are included.
Lake Kariba on the Zambezi is the world's largest reservoir by volume, with a nominal capacity of 180.6 km³. It sits behind the Kariba Dam on the border between Zambia and Zimbabwe, which was completed in 1959, and it is more than 223 km long. The dam's hydroelectric output is shared between the two countries.
The Bratsk Reservoir on the Angara River in Siberia holds 169 km³ of water and covers 5,470 km². It was formed behind the Bratsk Dam, whose concrete dam was completed in 1967 and has a 4,500 MW power plant. Flooding the Angara valley forced the relocation of riverside villages, which later inspired Valentin Rasputin's novel Farewell to Matyora.
Lake Volta in Ghana, created by the Akosombo Dam on the Volta River, has a nominal volume of 150 km³. It was completed in 1965 and is the largest reservoir in the world by surface area, at 8,502 km². The Akosombo Dam generates a substantial share of Ghana's electricity.
The Manicouagan Reservoir in Quebec, Canada, holds 141.85 km³ of water behind the Daniel-Johnson Dam on the Manicouagan River. It was completed in 1968, and it fills the ring of an eroded impact crater dated to about 214 million years ago.
The Guri Reservoir in Venezuela, formed by the Guri Dam on the Caroní River, has a capacity of 135 km³. The dam was completed in 1986, and its 10,235 MW power station was once the largest in the world by installed capacity, until Itaipu overtook it.
Lake Nasser, created by the Aswan High Dam on the Nile, has a total capacity of 132 km³. It straddles the border between Egypt and Sudan, was completed in 1971 and stretches about 550 km.
Williston Lake in British Columbia holds 74.3 km³ of water behind the W. A. C. Bennett Dam on the Peace River. The dam was completed in 1967, and its power station has a capacity of 2,907 MW. Among Canadian reservoirs, only Manicouagan holds more water.
Nigat Lake is the reservoir behind the Grand Ethiopian Renaissance Dam on the Blue Nile, and it holds 74 km³ at full supply level (59.2 km³ of that is active storage). Filling began in July 2020 and was finished in stages by 2024, and the dam was inaugurated in September 2025. Its power station has an installed capacity of 5,150 MW.
The Krasnoyarsk Reservoir on the Yenisei River in Siberia has a nominal volume of 73.3 km³. It was created by the Krasnoyarsk Dam and completed in 1967. The reservoir is about 388 km long in total, and the dam's power plant has an installed capacity of 6,000 MW.
The Zeya Reservoir in Russia's Amur Oblast, formed by the dam of the Zeya Hydroelectric Station on the Zeya River, holds 68.4 km³. It was completed in 1978 and is one of three Russian reservoirs in this top 10, alongside Bratsk and Krasnoyarsk.
| # | Name | Country | River | Dam | Year completed |
|---|---|---|---|---|---|
| 1 | Lake Kariba | Zambia & Zimbabwe | Zambezi | Kariba Dam | 1959 |
| 2 | Bratsk Reservoir | Russia | Angara | Bratsk Dam | 1964 |
| 3 | Lake Volta | Ghana | Volta | Akosombo Dam | 1965 |
| 4 | Manicouagan Reservoir | Canada | Manicouagan | Daniel-Johnson Dam | 1968 |
| 5 | Guri Reservoir | Venezuela | Caroní | Guri Dam | 1986 |
| 6 | Lake Nasser | Egypt & Sudan | Nile | Aswan High Dam | 1971 |
| 7 | Williston Lake | Canada | Peace River | W. A. C. Bennett Dam | 1967 |
| 8 | Nigat Lake (GERD reservoir) | Ethiopia | Blue Nile | Grand Ethiopian Renaissance Dam | 2025 |
| 9 | Krasnoyarsk Reservoir | Russia | Yenisei | Krasnoyarsk Dam | 1967 |
| 10 | Zeya Reservoir | Russia | Zeya | Zeya Dam | 1978 |
Reservoirs are ranked by nominal (total) volume in cubic kilometres (km³), meaning all the water held behind the dam at the maximum level. Active (usable) volume is not used. Figures follow the Chao et al. (2008) global reservoir database as reported in Wikipedia's List of reservoirs by volume, for eight of the ten. Two reservoirs are not covered by that database. For Lake Nasser, the figure is the 132 km³ total capacity of the Aswan High Dam. For Nigat Lake (GERD), the figure is the 74 km³ full-supply volume set by the 2013 International Panel of Experts design. The Wikipedia list still shows an older 79 km³ figure, and we do not use it. Williston (74.3 km³) and Nigat (74 km³) are only 0.3 km³ apart and come from different sources, so their order is within the margin of the data. Natural lakes with minor outlet control, such as Lake Superior, are excluded. Year is the completion year given in the Wikipedia list, except for GERD, which uses its 2025 inauguration.
Nominal volume is the total water storage capacity at the maximum designed water level. Active volume is the portion that can actually be used for its intended purpose (hydroelectricity, irrigation, etc.), minus the 'dead pool' volume that remains below the outlet level. Active volume is typically smaller than nominal volume.
Reservoir volume estimates vary with survey year, method and whether the figure is nominal or active volume. For example, Hydro-Québec gives Manicouagan as 137.9 km³ against the database's 141.85 km³, and Lake Kariba's own Wikipedia article cites 185 km³. We use the Chao database figure wherever it exists, so the comparison stays on one basis.
Some natural lakes, such as Lake Superior, have minor outlet control dams that regulate water levels. However, the great majority of the lake volume is natural. The table above excludes such augmented natural lakes — only reservoirs created by major dam construction are included.
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