Canada's Top 10
Hydroelectric Dams

The 7,722-MW Robert-Bourassa hydroelectric generating station is located on the La Grande River in northern Quebec. At 162 metres high and 2,835 metres wide, it is Canada's largest hydro project, the world's ninth largest, and the world's largest underground generating station at 137 metres below ground.

The project's 53-storey dam was constructed in James Bay, and its iconic spillway channels 17,600 cubic metres per second down 10 gigantic concrete steps, each the size of two football fields. This design, nicknamed "the giant's staircase," slows the water and prevents erosion. The reservoir covers 2,815 square kilometres and contains 61 billion cubic metres of water — enough for every person on Earth to draw 10,000 litres before it ran dry.

The 5,428-MW Churchill Falls generating station on the Churchill River is the second-largest hydroelectric power plant in Canada and the 10th largest in the world. Its reservoir is contained behind 88 rock-filled dikes rather than a dam, and the underground powerhouse consists of 11 Francis turbines, each rated at 493.5 MW.

The underground machine house was hollowed out of solid granite 305 metres under the earth — at the time of construction, the world's largest. It is three times as long as a football field, as tall as a 15-storey building, and held together with 11,000 steel rock bolts ranging from 11 to 25 feet in length. The Smallwood Reservoir covers 5,698 square kilometres.

James Bay is home to 11 hydroelectric projects, including La Grande-2A (2,106 MW), La Grande-3 (2,417 MW), and La Grande-4 (2,779 MW). Covering a combined area the size of New York State, the James Bay Project has a combined 16,527-MW capacity — approximately 40 per cent of Quebec's peak electricity load.

La Grande-4 is Canada's third-largest individual hydroelectric project. The dam stands 125 metres high, spans 3,800 metres and has a spillway capacity of 7,335 cubic metres per second. Together, the eight power stations of the La Grande Complex produce an average of 83 terawatt hours per year.

At 183 metres high, the W.A.C. Bennett Dam on the Peace River is one of the world's highest earth-filled dams. It spans 2,068 metres to create Williston Lake, Canada's third-largest artificial lake.

In the 1950s, Ray Williston proposed creating the "Power Trench" by turning sections of the Peace and Columbia river basins into power generation. The resulting Gordon M. Shrum generating station is located 150 metres below ground and houses 10 generating units.

The Revelstoke Dam spans the Columbia River five kilometres north of Revelstoke, B.C. The complex includes the 175-metre concrete gravity dam, a 122-metre-high earthfill dam on the west bank and a powerhouse in the riverbed. Five generating units run out of the powerhouse, each with a capacity of approximately 460 MW.

The dam creates a 130-kilometre reservoir extending to the tailwaters of the Mica Dam. Regulated release water from Mica provides almost three-quarters of the inflow, meaning Revelstoke operates as a run-of-the-river plant, with normal maximum reservoir fluctuations of 4.5 metres.

Constructed over a 30-year period, the Beauharnois Hydroelectric Power Station is located on the Saint Lawrence Seaway, just 45 minutes from Montreal. Its exceptional Art Deco architecture earned it designation as a National Historic Site.

Beauharnois' 36 generating units spread out over one kilometre make it Hydro-Québec's most powerful run-of-river project and one of the largest of its kind in the world.

The Daniel-Johnson Dam comprises 14 buttresses and 13 arches stretching across the Manicouagan River. It supplies water to the Manic-5 and Manic-5 PA power houses with a combined capacity of 2,660 MW. At 214 metres tall, 1,314 metres long, and containing 2,200,000 cubic metres of concrete, it is the largest multiple-arch-and-buttress dam in the world.

The dam's design uses less concrete than a gravity or embankment dam, and its composition was selected to withstand constant freezing and thawing. Of its 14 buttresses, the two forming the centre arch are 162 metres apart, and at its thickest point, the dam is 22.5 metres wide.

The Sir Adam Beck Generating Stations divert water from the Niagara and Welland rivers above Niagara Falls. Beck I first produced energy in 1922 with 10 generators. Beck II came online in 1954, with water diverted via two eight-kilometre tunnels running under the city of Niagara Falls.

Between 2003 and 2013, a major civil engineering upgrade added a 12.7-metre-diameter, 10.2-kilometre-long tunnel to divert water to 16 generators, increasing capacity by 150 MW — enough to power 160,000 homes.

The Kettle Generating Station is a run-of-river station located on the lower Nelson River, about six kilometres northwest of Gillam. Twelve 102-MW propeller turbine generators are housed in the power house, with each turbine discharging up to 270 cubic metres per second.

The power house covers 43 per cent of the river's 885-metre width, the spillway covers 22 per cent, and the earth-filled structure covers the remaining 35 per cent. Eight floodgates on the spillway can discharge water at up to 8,349 cubic metres per second.

The Keeyask Generating Station is a joint effort between Manitoba Hydro and four First Nations — Tataskweyak Cree Nation, War Lake First Nation, York Factory First Nation, and Fox Lake Cree Nation — working together as the Keeyask Hydropower Limited Partnership (KHLP).

The project is located on the lower Nelson River, 725 kilometres northeast of Winnipeg. North, central, and south dams were constructed through the Gull Rapids, founded on bedrock as zoned earth embankments with an impervious core, granular filters, and outer rockfill shells. The spillway is a concrete overflow type with seven bays fitted with motorized vertical lift gates.