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World’s Largest Reservoirs by Nominal Volume (Top 20)

World’s Largest Reservoirs by Nominal Volume (Top 20)

GeographyAugust 24, 2026

Reservoirs, often shown as large blue areas on maps of Africa or Canada where rivers once flowed, are artificial lakes formed by redirecting river courses. This report analyzes the eighteen largest reservoirs worldwide, ranked by water storage capacity in cubic kilometers. These reservoirs manage substantial volumes of water; some hold more water than entire seas, while others provide electricity to millions of households. The scale of these reservoirs is hard to conceptualize because of the immense quantities of water involved. This overview identifies the world’s largest reservoirs, emphasizing their geographic locations, associated dams, and storage capacities.

Zambia and Zimbabwe: Lake Kariba, the Largest Reservoir by Volume

Lake Kariba is recognized as the world’s largest reservoir by volume. Constructed on the Zambezi River, Zambia and Zimbabwe jointly manage it, and it contains approximately 180.6 cubic kilometers of water. Completed in 1959, the reservoir remains the largest artificial lake by volume. It extends approximately 280 kilometers and covers 5,580 square kilometers, with an average depth of 29 meters and maximum depths exceeding 90 meters. Kariba is notable for its transboundary location and its role in providing hydroelectric power to both nations. The reservoir supports cooperation between Zambia and Zimbabwe, supplying millions of people with water resources, fisheries, and electricity. Lake Kariba’s nominal volume of 180.6 cubic kilometers remains the largest of any reservoir worldwide.

The Kariba Dam was completed in 1959 on the Zambezi River between Zambia and Zimbabwe.
The lake stretches about 280 kilometers along the Zambezi Valley.
Its surface area covers approximately 5,580 square kilometers of open water.
Lake Kariba reaches a maximum depth of nearly 97 meters in its deepest channels.
Kariba’s storage volume is nearly four times greater than that of the reservoir created by China’s Three Gorges Dam.
The lake supports a significant commercial fishing industry, especially for kapenta, a small sardine-like fish.
Creating Lake Kariba required resettling thousands of people, making it one of the largest forced relocations associated with a dam project.

Russia: Bratsk Reservoir as the Second Largest by Volume

Russia appears more frequently than any other nation among the world’s largest reservoirs, beginning with the Bratsk Reservoir. Located on the Angara River in Siberia, Bratsk contains about 169.0 cubic kilometers of water, making it the world’s second-largest reservoir. Completed in 1964, the Bratsk Dam remains a major hydroelectric project in Siberia. Its construction was a major engineering achievement, especially given the region’s extreme winter temperatures, which can fall below minus forty degrees Fahrenheit. The reservoir extends over 500 kilometers and covers approximately 5,470 square kilometers, following the natural contours of river valleys rather than forming a single, wide basin. Bratsk exemplifies the capacity to transform landscapes in harsh climates. This reservoir is a key factor in Russia’s prominence in hydroelectric power and is widely referenced in academic research.

Bratsk Reservoir holds a nominal volume of approximately 169.0 cubic kilometers.
The reservoir sits on the Angara River in the Irkutsk Oblast region of Siberia.
Construction of the Bratsk Dam was completed in 1964 after years of grueling labor in Siberia.
The reservoir stretches more than 500 kilometers along the river valley.
Its surface area measures roughly 5,470 square kilometers.
The reservoir reaches a maximum depth of more than 150 meters in certain stretches.
Bratsk remains the world’s second-largest reservoir by storage capacity.
The associated power station generates around 22.6 terawatt-hours of electricity annually.

Ghana: Lake Volta and the Largest Reservoir Surface Area

Lake Volta is the world’s third-largest reservoir by volume, containing approximately 150.0 cubic kilometers of water. It also has the largest surface area of any reservoir, spanning 8,502 square kilometers, which constitutes about 3.6 percent of Ghana’s land area. The Akosombo Dam, completed in 1965, created Lake Volta and significantly transformed the national landscape. The reservoir’s formation flooded about 740 villages and displaced nearly 78,000 people, creating substantial social and economic impacts. Today, Lake Volta supplies power to an aluminum smelter, generates most of Ghana’s electricity, and supports a significant fishing industry. The reservoir presents both opportunities and challenges for local communities.

Lake Volta holds a nominal volume of about 150.0 cubic kilometers.
The lake covers 8,502 square kilometers, the largest surface area of any reservoir worldwide.
The Akosombo Dam, which created it, was completed in 1965 on the Volta River.
Roughly 78,000 people were resettled as the lake formed.
Lake Volta stretches around 400 kilometers from north to south across Ghana.
The Akosombo hydroelectric plant generates about 912 megawatts of electricity.
Main islands within the lake include Dodi, Dwarf, and Kporve.
The lake remains a critical inland transportation route, connecting northern Ghana to the coast.

Canada: Manicouagan Reservoir, Referred to as the Eye of Quebec

The Manicouagan Reservoir in Canada is the fourth largest globally, containing approximately 141.8 cubic kilometers of water. Constructed within an ancient impact crater, one of the five largest on Earth, the reservoir exhibits a nearly circular shape and is often referred to as the Eye of Quebec. The Daniel-Johnson Dam, completed in 1970, is recognized as the world’s largest multiple-arch buttress dam. The reservoir encircles René-Levasseur Island, the world’s second-largest lake island. Developed by Hydro-Québec, this system supplies power to the Manic-5 and Manic-5-PA generating stations, which collectively produce over 2,600 megawatts of electricity. Manicouagan exemplifies the intersection of geological history and engineering achievement.

Manicouagan Reservoir holds a nominal volume of approximately 141.8 cubic kilometers.
The reservoir formed within an ancient meteorite impact crater in Quebec, Canada.
The Daniel-Johnson Dam, completed in 1970, is the world’s largest multiple-arch buttress dam.
The reservoir surrounds René-Levasseur Island, the world’s second-largest lake island.
The reservoir reaches a maximum depth of around 350 meters in the deepest zone.
Combined generating stations at the site produce over 2,600 megawatts of hydroelectric power.
The dam contains 2.2 million cubic meters of concrete, representing a substantial volume.
The reservoir covers roughly 1,950 to 2,000 square kilometers.

Venezuela: Guri Reservoir as a National Electricity Source

The Guri Reservoir in Venezuela is the world’s fifth-largest, with a storage volume of about 135.0 cubic kilometers. Created by the Guri Dam on the Caroní River, it supplies the Simón Bolívar Hydroelectric Plant, which was once the world’s largest power station by installed capacity. Construction of the dam occurred between 1963 and 1986, spanning more than two decades. Although Venezuela is best known for oil production, this hydroelectric complex generates most of the nation’s electricity. The dam measures over 7,400 meters in length and 162 meters in height. The plant has a capacity exceeding 10,000 megawatts and produces about 47,000 gigawatt-hours annually, serving a critical role in meeting the country’s energy needs.

Guri Reservoir holds a nominal volume of approximately 135.0 cubic kilometers.
The reservoir sits on the Caroní River in Bolívar State, eastern Venezuela.
Construction of the Guri Dam began in 1963 and finished in stages by 1986.
The Simón Bolívar Hydroelectric Plant has an installed capacity of more than 10,000 megawatts.
The dam stretches more than 7,400 meters long, making it one of the longest dams in the world.
Guri Reservoir covers about 4,250 square kilometers.
The plant generates roughly 47,000 gigawatt-hours of electricity every year.
Guri once held the title of the world’s largest hydroelectric facility by capacity.

Egypt and Sudan: Lake Nasser and the Transformation of the Nile River

Lake Nasser is the world’s sixth-largest reservoir, with a storage volume of about 132.0 cubic kilometers. Formed by the completion of the Aswan High Dam in 1971, the reservoir spans both Egypt and Sudan. The northern two-thirds of the lake lies in Egypt, while the southern portion, known as Lake Nubia, lies in Sudan. Creating Lake Nasser required relocating the ancient temples of Abu Simbel and Philae to prevent their submersion, a major archaeological undertaking. The reservoir is about 480 kilometers long and contributed to a 30 percent increase in Egypt’s arable land after it filled. Today, Lake Nasser supports diverse wildlife, including significant crocodile populations, and attracts tourists interested in both natural and historical sites. This case illustrates the combined practical and cultural significance of large-scale water infrastructure projects.

Lake Nasser holds a nominal volume of approximately 132.0 cubic kilometers.
The Aswan High Dam, which created it, was completed and dedicated in 1971.
The lake spans two countries, with most of it lying in Egypt and the rest in Sudan.
Ancient temples at Abu Simbel and Philae were relocated to avoid submersion.
Lake Nasser stretches nearly 480 kilometers along the Nile.
After filling, the reservoir increased Egypt’s arable land by roughly 30 percent.
The Aswan High Dam provides Egypt with about 2,000 megawatts of hydroelectric power.
Lake Nasser is a known habitat for large populations of Nile crocodiles.

Ethiopia: The Millennium Reservoir and Its Historical Context

The Millennium Reservoir in Ethiopia, created by the Grand Ethiopian Renaissance Dam, contains about 79.0 cubic kilometers of water, making it the seventh-largest reservoir globally. Completed in 2023, it is the most recent reservoir among those discussed. The dam has been central to negotiations between Ethiopia, Sudan, and Egypt regarding Nile water rights for over a decade. Situated on the Blue Nile, which subsequently merges with the main Nile before entering Sudan and Egypt, the project is expected to enable Ethiopia to become a major electricity exporter in East Africa, thereby transforming its national economy.

The Millennium Reservoir holds a nominal volume of approximately 79.0 cubic kilometers.
It formed behind the Grand Ethiopian Renaissance Dam on the Blue Nile River.
The dam was completed in 2023, making it the newest reservoir on this list.
The project has sparked years of diplomatic tension with Sudan and Egypt.
Ethiopia intends to use the dam to become a major electricity exporter in Africa.
The Blue Nile feeds directly into the main Nile River system downstream.
The reservoir represents one of the largest infrastructure investments in Ethiopian history.
Filling the reservoir took years of careful, phased work to avoid downstream disruption.

Canada: Williston Lake in British Columbia

Williston Lake, the world’s eighth-largest reservoir, has a storage volume of about 74.3 cubic kilometers. It is the largest freshwater body in British Columbia and was formed by the completion of the W. A. C. Bennett Dam in 1968 on the Peace River. The dam is among the world’s largest earthfill dams. Williston Lake produces approximately 15 terawatt-hours of electricity annually, supplying more than one-third of British Columbia’s power during peak periods. The reservoir extends about 250 kilometers through remote wilderness, and its creation flooded traditional Tsay Keh Dene First Nation territory. The Gordon M. Shrum Generating Station, located at the dam, remains the largest power station in the province. Despite limited public recognition, Williston Lake ranks among the world’s largest reservoirs.

Williston Lake holds a nominal volume of approximately 74.3 cubic kilometers.
The W. A. C. Bennett Dam, which created it, was completed in 1968 on the Peace River.
Williston Lake is the largest body of fresh water in British Columbia.
The reservoir stretches roughly 250 kilometers from north to south.
Construction flooded the traditional territory of the Tsleil-Waututh First Nation.
The Gordon M. Shrum Generating Station remains British Columbia’s largest power station.
The dam supplies more than a third of British Columbia’s electricity at peak times.
Williston Lake ranks as the world’s seventh-largest reservoir by some measurements.

Russia: Krasnoyarsk Reservoir on the Yenisei River

Krasnoyarsk Reservoir, also known as the Krasnoyarsk Sea, is the world’s ninth-largest reservoir, with a storage volume of about 73.3 cubic kilometers. Located on the Yenisei River in Siberia, it is Russia’s second-largest reservoir after Bratsk. The reservoir extends nearly 388 kilometers, although the straight-line distance from its upstream end to the dam is about 250 kilometers, reflecting its winding course. Its creation flooded one of Siberia’s oldest Russian settlements. The reservoir supports several towns along its shoreline, including Abakan. Passenger hydrofoils operated on the reservoir for many years; however, this service ended in the early 1990s. Today, the reservoir is used primarily for hydroelectric power generation.

Krasnoyarsk Reservoir holds a nominal volume of approximately 73.3 cubic kilometers.
The reservoir sits on the Yenisei River and is nicknamed the Krasnoyarsk Sea.
It is Russia’s second-largest reservoir after the Bratsk Reservoir.
The reservoir stretches about 388 kilometers long.
Its formation flooded one of Siberia’s earliest Russian settlements.
Regional centers Abakan and Krasnoturansk sit directly along its shoreline.
Passenger hydrofoils operated on the reservoir until the early 1990s.
The reservoir’s widest points stretch about 15 kilometers across.

Russia: Zeya Reservoir as the Third Largest in the Country

The Zeya Reservoir, with a storage volume of approximately 68.4 cubic kilometers, is the tenth-largest reservoir globally and Russia’s third entry on this list, highlighting the country’s expertise in reservoir engineering. Constructed on the Zeya River in Russia’s Far East, the Zeya Dam was completed in 1978 as part of a series of major Soviet-era hydroelectric projects. This development reflects Russia’s historical commitment to large-scale river modification. The Amur River basin, into which the Zeya flows, is a critical watershed in northeastern Asia, and the reservoir plays a significant role in regional flood control. Although Zeya receives less international attention than reservoirs such as Kariba or Nasser, it remains among the world’s ten largest. Many major engineering projects are located in remote regions, and Zeya exemplifies the enduring impact of such infrastructure.

The reservoir sits on the Zeya River in Russia’s Far East region.
The Zeya Dam was completed in 1978 after years of Soviet-era construction.
Zeya is Russia’s third-largest reservoir by volume and one of the world’s ten largest.
The reservoir plays a major flood-control role in the Amur River basin.
It remains far less internationally known than reservoirs like Kariba or Nasser.
The dam contributes meaningfully to Russia’s Far East electricity supply.
The Amur basin it feeds into is one of northeastern Asia’s key watersheds.

Canada: Robert-Bourassa Reservoir as the Third Largest in the Country

The Robert-Bourassa Reservoir, with a storage capacity of approximately 61.7 cubic kilometers, is Canada’s third-largest reservoir among the world’s largest reservoirs and serves as a central component of the James Bay hydroelectric project in Quebec. This reservoir supplies the Robert-Bourassa generating station, one of the world’s largest underground power stations, built as part of Hydro-Québec’s initiative to harness northern rivers for electricity generation. The James Bay project established Quebec as a major hydroelectric producer, enabling electricity exports to the northeastern United States. Located in a remote, sparsely populated region of northern Quebec, the reservoir powers Montreal, supplies electricity to New York, and supports industries over long distances. The scale of land transformation required for this project is substantial. Indigenous communities, particularly the Cree Nation, were significantly affected, and their relationship with Hydro-Québec has evolved since construction began. Robert-Bourassa now represents both an engineering achievement and the ongoing discourse at the intersection of large infrastructure projects, Indigenous rights, and land use.

Robert-Bourassa Reservoir holds a nominal volume of approximately 61.7 cubic kilometers.
The reservoir is part of Quebec’s massive James Bay hydroelectric project.
It feeds one of the world’s largest underground power stations.
The project allowed Quebec to export electricity to the northeastern United States.
The reservoir sits in a remote, sparsely populated region of northern Quebec.
Cree Nation communities were significantly affected by the project’s construction.
Hydro-Québec relies on this reservoir as a cornerstone of its generating network.
The James Bay project remains one of North America’s largest hydroelectric developments.

Canada: La Grande-3 Nord Reservoir and Ongoing Expansion

The La Grande-3 Nord Reservoir, with a storage volume of approximately 60.0 cubic kilometers, further strengthens Canada’s position among the world’s largest reservoirs and underscores the significant concentration of freshwater storage in northern Canada. This reservoir is part of the extensive La Grande hydroelectric complex, a network of dams and reservoirs in northern Quebec that collectively constitute one of the most ambitious energy projects undertaken by a single utility. The combined operation of La Grande-3, Robert-Bourassa, Caniapiscau, and other reservoirs distinguishes Quebec in this context. The La Grande River was selected for its substantial natural flow and relatively flat terrain, which made it easier to create large reservoirs. Forming these reservoirs required local wildlife, particularly caribou herds, to adapt to altered landscapes. Ongoing research examines how large northern reservoirs influence local climate, as substantial bodies of water can affect temperature and precipitation patterns in ways smaller lakes cannot.

La Grande-3 Nord Reservoir holds a nominal volume of approximately 60.0 cubic kilometers.
The reservoir is part of the broader La Grande hydroelectric complex in Quebec.
It represents one component of one of the world’s largest energy megaprojects.
The La Grande River was chosen for its massive natural flow and flat terrain.
The reservoir’s creation affected caribou migration patterns in the region.
Researchers study how large northern reservoirs may influence local climate.
The reservoir works alongside others like Robert-Bourassa within the same system.
Quebec’s La Grande complex generates a significant share of the province’s electricity.

Russia: Ust-Ilimsk Reservoir as the Fourth Largest in the Country

Ust-Ilimsk Reservoir contains approximately 59.3 cubic kilometers of water, making it Russia’s fourth-largest reservoir and underscoring the national grid’s heavy reliance on rivers. Built on the Angara River downstream of the Bratsk Reservoir, it is part of a chain of dams Soviet engineers designed to maximize hydroelectric output. This phased approach reflects long-term planning, with each dam contributing to the efficiency of the next. The Ust-Ilimsk Hydroelectric Power Station has supported local industries, particularly timber and pulp production, which are vital to the regional economy. These reservoirs are integral not only to electricity generation but also to broader economic development, providing affordable and reliable power. Along the Angara, the Ust-Ilimsk Reservoir, along with Bratsk and other dams, contributes to one of the world’s most engineered river systems. The Ust-Ilimsk Reservoir has a nominal volume of about 59.3 cubic kilometers.

The reservoir sits on the Angara River downstream from the Bratsk Reservoir.
It forms part of a cascading chain of Soviet-era hydroelectric dams.
The associated power station supports regional timber and pulp industries.
Ust-Ilimsk is the world’s fourth-largest reservoir.
The Angara River system hosts several of the world’s biggest reservoirs in sequence.
Long-term Soviet planning shaped this cascading dam network across decades.
The reservoir contributes to one of the most heavily engineered rivers on Earth.

Russia: Boguchany Reservoir and Ongoing Expansion

Boguchany Reservoir contains approximately 58.2 cubic kilometers of water and is among the most recently completed major reservoirs on this list. Its construction spanned several decades and concluded in the twenty-first century. Located on the Angara River downstream from both Bratsk and Ust-Ilimsk, it constitutes the final major link in the chain of Siberian dams. Initiated during the Soviet era, the project’s completion was delayed by significant political and economic transitions, including the dissolution of the USSR. The Boguchany Dam was constructed alongside an integrated aluminum smelter, illustrating the multipurpose nature of such infrastructure. The extended construction period exemplifies how political and economic instability can delay even critical projects. Today, the reservoir supports both regional electricity demand and heavy industry along the Angara corridor, underscoring the persistence required to achieve large-scale infrastructure goals.

Boguchany Reservoir holds a nominal volume of approximately 58.2 cubic kilometers.
The reservoir sits on the Angara River, downstream of Bratsk and Ust-Ilimsk.
Construction spanned decades, beginning in the Soviet era and finishing much later.
The reservoir represents the final major link in the Angara River dam chain.
An integrated aluminum smelter was built alongside the Boguchany Dam.
Political and economic upheaval significantly delayed the project’s completion.
Boguchany supports both regional electricity needs and heavy industry.
The Angara corridor now hosts one of the densest clusters of major reservoirs worldwide.

Russia: Kuybyshev Reservoir on the Volga River

The Kuybyshev Reservoir, with a storage volume of about 58.0 cubic kilometers, sits on the Volga River in European Russia, near major population centers. This distinguishes Kuybyshev from most Siberian reservoirs, as it directly serves large cities such as Samara and Kazan. The reservoir exemplifies the extension of Russian reservoir engineering beyond Siberia, with the Volga River transformed into a series of substantial artificial lakes. Kuybyshev ranks among Europe’s largest reservoirs and holds distinct cultural significance compared with its Siberian counterparts. It supports agriculture, fishing, and shipping along the Volga, a historically important trade route. The reservoir’s creation flooded parts of historic riverside towns, and local oral histories still record communities that existed before the inundation.

Kuybyshev Reservoir holds a nominal volume of approximately 58.0 cubic kilometers.
The reservoir sits on the Volga River in European Russia, near Samara and Kazan.
It ranks among Europe’s largest reservoirs.
Kuybyshev supports major agriculture, fishing, and shipping activity along the Volga.
The reservoir’s creation flooded several historic riverside towns and villages.
It differs from Russia’s Siberian reservoirs by serving densely populated regions directly.
The Volga River hosts a whole chain of reservoirs, with Kuybyshev among the largest.
Local oral histories still recall communities that existed before the flooding occurred.

Mozambique: Cahora Bassa Reservoir on the Zambezi River

The Cahora Bassa Reservoir, with a storage capacity of approximately 55.8 cubic kilometers, lies farther downstream on the Zambezi River, which also feeds Lake Kariba, making it one of two major reservoirs on this river. Completed in the mid-1970s, the Cahora Bassa Dam has served as a primary source of electricity for Mozambique, with a significant portion of its output transmitted to South Africa via extensive power lines. This highlights the transnational economic impact of large reservoirs. The reservoir altered the Zambezi’s natural downstream flooding patterns, affecting agricultural and fishing communities reliant on seasonal cycles. Mozambique’s prolonged civil war, which followed the dam’s construction, delayed the realization of the reservoir’s full economic benefits. Only in recent decades has Cahora Bassa fulfilled its intended role as a key economic asset, underscoring the need for political stability for major infrastructure projects to succeed.

Cahora Bassa Reservoir holds a nominal volume of approximately 55.8 cubic kilometers.
The reservoir sits on the Zambezi River downstream from Lake Kariba.
Mozambique completed the Cahora Bassa Dam in the mid-1970s.
A significant share of the dam’s electricity is exported directly to South Africa.
The reservoir altered natural seasonal flooding patterns along the lower Zambezi.
Mozambique’s civil war delayed the dam’s full economic benefits for years.
Cahora Bassa and Lake Kariba together dominate the Zambezi’s hydroelectric output.
The reservoir remains one of Mozambique’s most important infrastructure assets.

Brazil: Serra da Mesa Reservoir

The Serra da Mesa Reservoir, with a storage volume of approximately 54.4 cubic kilometers, is Brazil’s only representative among the world’s largest reservoirs. Located in the state of Goiás on the Tocantins River, Serra da Mesa is notable given Brazil’s global association with the Amazon rather than artificial lakes. Completed in the late 1990s, the dam is relatively modern compared to most other major reservoirs. Beyond its primary function of electricity generation, Serra da Mesa has fostered a growing tourism sector, attracting visitors for its clear waters, scuba diving opportunities, and dramatic sandstone canyons. The reservoir also plays a critical role in stabilizing Brazil’s national electricity grid, particularly during dry seasons when other hydroelectric plants produce less. This example demonstrates how reservoirs initially constructed for power generation can develop additional uses over time.

Serra da Mesa Reservoir holds a nominal volume of approximately 54.4 cubic kilometers.
The reservoir sits on the Tocantins River in the Brazilian state of Goiás.
It is Brazil’s only representative among the world’s largest reservoirs.
The dam was completed in the late 1990s, making it relatively modern.
Serra da Mesa has developed a notable tourism and scuba diving industry.
Dramatic sandstone canyon formations surround portions of the reservoir.
The reservoir helps stabilize Brazil’s national grid during dry seasons.
It remains one of South America’s largest reservoirs by nominal volume.

Canada: Caniapiscau Reservoir as the Fourth Largest in the Country

The Caniapiscau Reservoir, with a storage capacity of approximately 53.8 cubic kilometers, ranks among the world’s eighteen largest reservoirs and is Canada’s fourth-largest, highlighting the nation’s expertise in reservoir engineering. Located in northern Quebec, Caniapiscau is a key component of the extensive James Bay hydroelectric network, alongside Robert-Bourassa and La Grande-3 Nord. The reservoir primarily functions as a large water storage basin, channeling water downstream into the La Grande River system to enhance electricity generation at multiple power stations. Situated in a subarctic region and frozen for much of the year, the reservoir’s operation requires specialized water management strategies developed by Hydro-Québec engineers. Indigenous communities, particularly the Cree, have engaged with Hydro-Québec for decades regarding land use, compensation, and environmental stewardship associated with the reservoir. Caniapiscau illustrates the significant yet often unrecognized contributions of large-scale infrastructure in remote regions.

Caniapiscau Reservoir holds a nominal volume of approximately 53.8 cubic kilometers.
The reservoir sits in northern Quebec as part of the James Bay hydroelectric network.
It gives Canada four total reservoirs among the world’s eighteen largest by volume.
Caniapiscau primarily functions as a water storage basin feeding other stations downstream.
The reservoir sits in a subarctic environment and freezes for much of the year.
Cree communities have long-standing relationships with Hydro-Québec tied to this project.
Caniapiscau works together with Robert-Bourassa and La Grande-3 Nord in one system.
It represents the final entry in this ranking of the world’s eighteen largest reservoirs.

Significance of Reservoir Storage Capacities

Collectively, these eighteen reservoirs contain volumes of water that are challenging to conceptualize, with capacities sufficient to influence regional climates, supply electricity to entire nations, and necessitate the relocation of hundreds of thousands of individuals. For example, the difference in capacity between Lake Kariba (180.6 cubic kilometers) and Caniapiscau (53.8 cubic kilometers) amounts to tens of billions of cubic meters. Russia and Canada dominate this list due to their extensive river systems and longstanding commitment to large-scale river engineering. Africa contributes three major reservoirs—Kariba, Volta, and Cahora Bassa—while Venezuela, Egypt, Sudan, Ethiopia, and Brazil each have significant entries. These reservoirs share not only their scale but also the ambition behind their construction, the profound changes they brought to affected communities, and the continued reliance of millions on them for electricity, water, food, and livelihoods.

These Are the World’s 20 Largest Reservoirs by Nominal Volume:

Rank	Reservoir	Country/Countries	Volume (km³)
1	Lake Kariba	Zambia, Zimbabwe	180.6
2	Bratsk Reservoir	Russia	169.0
3	Lake Volta	Ghana	150.0
4	Manicouagan Reservoir	Canada	141.85
5	Guri Reservoir	Venezuela	135.0
6	Lake Nasser	Egypt, Sudan	132.0
7	Millennium Reservoir (Grand Ethiopian Renaissance Dam)	Ethiopia	79.0
8	Williston Lake	Canada	74.3
9	Krasnoyarsk Reservoir	Russia	73.3
10	Zeya Reservoir	Russia	68.4
11	Robert-Bourassa Reservoir	Canada	61.71
12	La Grande-3 Nord Reservoir	Canada	60.02
13	Ust-Ilimsk Reservoir	Russia	59.3
14	Boguchany Reservoir	Russia	58.2
15	Kuybyshev Reservoir	Russia	58.0
16	Cahora Bassa	Mozambique	55.8
17	Serra da Mesa Reservoir	Brazil	54.4
18	Caniapiscau Reservoir	Canada	53.8
19	Bukhtarma Reservoir	Kazakhstan	53.0
20	Danjiangkou Reservoir	China	51.6