The Largest Man-Made Lakes in the World, by Area and by Volume

The largest man-made lake in the world by surface area is Lake Volta in Ghana, which covers about 8,500 km² behind the Akosombo Dam, completed in 1965. The largest by volume is Lake Kariba on the Zambia–Zimbabwe border, holding 185 km³ behind the Kariba Dam (1959). Ranked by the water surface mapped from satellites, the top five are Lake Volta, Canada's Smallwood Reservoir, Lake Nasser, Lake Kariba and Russia's Kuybyshev Reservoir. Ranked by volume, they are Lake Kariba, the Bratsk Reservoir, Lake Nasser, Lake Volta and Venezuela's Guri Reservoir. Both lists leave out natural lakes whose level a dam controls, such as Lake Victoria: it is a natural lake, even though a dam has managed its outflow since 1954.

Both rankings come from Global Dam Watch (GDW) 1.0, published in 2024 by Lehner and colleagues, which merges the Global Reservoir and Dam database (GRanD) with newer satellite inventories. It holds 41,145 dams and barriers, 35,321 with a reservoir area, and gives storage in million cubic metres, which we convert to cubic kilometres (1 km³ = 1,000 million m³, a billion cubic metres). We removed the 209 records GDW marks as natural lakes with a control structure, one reservoir that no longer exists and one barrage that stores nothing.

Ranking one: surface area, where Lake Volta wins on either measure

For most big reservoirs GDW carries two areas: an outline traced from satellite data and a figure reported by the operator or the literature, usually at full supply. They rarely agree. Lake Volta's outline covers 6,019 km², just 71% of the 8,500 km² reported, because an outline catches a lake at whatever level it stood when the image was taken. The Volta River Authority, which runs the dam, gives about 8,500 km², and about 150 billion m³ at a full supply level of 84.73 m.

We rank by the mapped outline, GDW's own representative figure, because it is measured the same way for every reservoir and is what the shapes at the top of this page show, all at one scale. Lake Volta comes first on both; our Akosombo Dam profile covers how it was built.

Second place depends on which area you trust. On the mapped outline it is the Smallwood Reservoir in Labrador, only 3% smaller than Volta at 5,841 km². GDW's reported figure for Smallwood is a mere 2,200 km², which would drop it to 23rd place, while The Canadian Encyclopedia puts it at 6,527 km². It is also a borderline case: formed by damming the Churchill River and diking others, it now takes in hundreds of former lakes, Michikamau and Lobstick the largest. On reported areas the runner-up is Lake Nasser, at 6,500 km² across Egypt and Sudan, followed by the Kuybyshev Reservoir at 6,150 km².

Russia places three reservoirs in the top eight, all completed between 1941 and 1964: the Rybinsk and Kuybyshev reservoirs on the Volga and the Bratsk Reservoir on the Angara. Africa has three more, on the Volta, the Nile and the Zambezi. Smallwood and Guri complete the eight. China, India and the United States have no reservoir in the top 25: their biggest by mapped area rank 29th, 56th and 36th. The Three Gorges Reservoir maps at 852 km² (51st), and Lake Mead, behind the Hoover Dam, at 581 km² (79th).

Ranking two: volume, where depth beats spread

Volume rewards depth, so this list reshuffles. Dividing each reservoir's capacity by its reported area gives a rough mean depth: about 33 m for Kariba and 31 m for Bratsk, 17 m for Volta and 25 m for Nasser, but only 9 m for Kuybyshev. That is why a reservoir fifth by area falls to 15th by volume.

Lake Kariba's 185 km³ is the same figure the Zambezi River Authority gives for the lake at its maximum retention level of 487.8 m. Not all of it can be used. The authority's July 2026 statement reported 31.46 billion m³ of usable water as 48.55 percent of live storage, which puts the live storage at about 65 km³, roughly 35% of the total. The concrete arch that holds it all back has its own profile on this site.

The next three are close. GDW puts the Bratsk Reservoir at 169 km³; a 2015 study of the Angara cascade in Environmental Earth Sciences gives 168.2 km³. Lake Nasser holds 162 km³, and Lake Volta 148 km³, against the Volta River Authority's rounder "approximately 150 billion m³". Guri, on the Caroní in Venezuela, completes the top five with 135 km³. Together those five hold 799 km³.

Behind them sits a near tie at about 74 km³: Williston Lake in British Columbia (74.3 km³), the reservoir of the Grand Ethiopian Renaissance Dam (74.0 km³) and the Krasnoyarsk Reservoir on the Yenisei (73.3 km³). For the Ethiopian dam GDW gives its maximum capacity and notes that filling was still under way in 2023. The Kuybyshev Reservoir, by contrast, holds 58.0 km³ in GDW and 57.3 km³ according to its operator, RusHydro, which still calls it the largest reservoir on the Volga.

One reservoir is missing on purpose. GDW 1.0 still lists Ukraine's Kakhovka Reservoir, 2,098 km² and 18.2 km³, which would rank 21st by area. Its dam was destroyed on 6 June 2023, and the authors of a 2024 study from Kharkiv write that by the end of that month the reservoir "ceased to exist". We also dropped India's Farakka Barrage, whose figure in GDW is an annual diversion volume rather than storage.

What the biggest reservoirs were built for

Almost all of the giants were built for electricity. The Volta River Authority was set up under the Volta River Development Act of 1961 to generate power, and Akosombo started with 588 MW; a retrofit completed in 2005 took it to 1,020 MW, according to the authority's own paper. Kariba's double-curvature concrete arch is 128 m high and 617 m long at the crest, and feeds two power stations, 1,080 MW on the north bank and 1,050 MW on the south, per the Zambezi River Authority. On the Angara, the Bratsk dam rises 125 m and flooded a 570 km reach of the valley; the 2015 study of the Angara cascade says its reservoirs help prevent floods, but their main objective is hydroelectric power.

Why Lake Victoria isn't on this list

Lake Victoria is a natural lake. Uganda's Owen Falls Dam, now called Nalubaale, has controlled its outflow since 1954, with releases set to mimic the flow that once ran naturally over Ripon Falls, as Songa and Sewagudde describe. Because of that dam, the database lists the whole lake, all 66,867 km² of it, as if it were a reservoir. But a dam that regulates a natural lake does not make the lake man-made, so Victoria and the other dam-controlled natural lakes, Lake Baikal among them, are left out of both rankings. Our Lake Victoria guide covers the lake itself.

The map shows where the giants cluster. Of the 46 man-made lakes of 1,000 km² or more, Russia has 16, Canada 8 and Brazil 5. Another 21 that size are dam-controlled natural lakes, 8 in Canada; the map leaves them out.

How the two lists were built

The area ranking uses GDW's representative area, which for every reservoir in the top ten is its mapped polygon; the volume ranking uses GDW's storage capacity, which favours the maximum or gross figure where a source gives one. Big reservoirs' capacities come from operators and the literature; most small ones are statistical estimates. Hero areas, computed on an equal-area projection centred on each reservoir, match GDW's polygon areas to within 2 percent. The exclusion follows GDW's lake-control flag mechanically (172 records marked "yes", 33 "maybe", 4 "enlarged"), and GDW's documentation says that flag "currently only contains limited entries". So Smallwood, which swallowed hundreds of older lakes, stays in, while Quebec's Manicouagan, which filled an impact crater and merged two older lakes (NASA), is flagged and out; at GDW's 1,803 km² and 35.2 km³ it would not make either top 12 anyway. You can download the data as a CSV with all 168 reservoirs and regulated lakes over 500 km² or 10 km³, their two areas, capacity, flags and our reason for any exclusion; if you want the area-against-volume scatter we left out, hand the file to Parity and it will draw one for you. Sources:

• Lehner et al. (2024), Global Dam Watch database version 1.0, figshare, doi:10.6084/m9.figshare.25988293: 41,145 river barriers and 35,295 reservoir polygons, with GRanD's surface areas, storage capacities and lake-control flags. CC BY 4.0 (stated in the GDW technical documentation shipped with the data).
• Lehner et al. (2024), The Global Dam Watch database of river barrier and reservoir information for large-scale applications, Scientific Data 11: How GDW was built from GRanD, GOODD, GROD and other sources. Open access.
• Zambezi River Authority: Kariba HES technical data, and press statement on the hydrological outlook at Kariba Dam, 21 July 2026: Capacity of Lake Kariba at maximum retention level; live storage figures; the dam (128 m double-curvature arch, 617 m crest) and its 1,080 MW and 1,050 MW power stations.
• Amekor, E. M. K. (Volta River Authority), Integrated management of the water resources of the Volta Lake in Ghana: the VRA experience (IWRA conference paper): Surface area and volume of Lake Volta at full supply level; VRA's founding under the 1961 Act; Akosombo's 588 MW and 1,020 MW after the 2005 retrofit.
• RusHydro, Zhigulyovsk HPP branch website: Capacity of the Kuybyshev Reservoir.
• Jaguś, Rzętała and Rzętała (2015), Water storage possibilities in Lake Baikal and in reservoirs impounded by the dams of the Angara River cascade, Environmental Earth Sciences 73: 621–628: Bratsk Reservoir volume (168.2 km³), dam height (125 m), the 570 km flooded reach, and hydropower as the cascade's main objective (abstract read via FAO AGRIS).
• Chernogor et al. (2024), Ecological consequences of the catastrophic destruction of the Kakhovka reservoir dam, Visnyk of V. N. Karazin Kharkiv National University, series Geology. Geography. Ecology 61: Date of the dam's destruction and the reservoir's design area and volume.
• Songa and Sewagudde (2007), Supply and demand: the effects of development on the hydrology of Lake Victoria, Mississippi Water Resources Conference: Owen Falls (Nalubaale) Dam, commissioned April 1954, and the 'Agreed Curve' release rule.
• The Canadian Encyclopedia: Smallwood Reservoir (Ian Maccallum): Area and how the reservoir absorbed existing lakes.
• Natural Earth land, 1:110m and 1:50m, via the world-atlas package: Public domain. Background maps only.

Every one of these lakes needed a dam, and to see which nations have built the most, read our ranking of the countries with the most dams.