Churchill Falls
From Biocrawler, the free encyclopedia.
Churchill Falls are spectacular waterfalls, 245 ft (75 m) high, on the Churchill River in Labrador, Canada. The falls were first explored in 1839 by John MacLean, a trader of the Hudson Bay Company. MacLean named the river the Hamilton River after Newfoundland Governor, Sir Charles Hamilton. The falls were known as Grand Falls until 1965 when both names were changed to the Churchill River and Churchill Falls to honour the former British Prime Minister, Sir Winston Churchill. Churchill Falls has the largest hydroelectric-generating capacity in North America (5,248 MW installed, expandable to 9,252 MW) and is the largest underground power station in the world.
Four miles (6.4 km) above the falls, the Churchill River narrows to 200 ft (61 m) and negotiates a series of rapids before dropping into MacLean Canyon, from which sheer cliffs rise several hundred feet on either side. The river flows 12 miles (19 km) through the canyon over a series of rapids. The total drop from the rapids above the main falls to the end of MacLean Canyon is 1,038 ft (316 m).
| Contents |
Hydroelectic Power Project
In 1894, Albert Peter Low of the Geological Survey of Canada reached the Grand Falls during his study of the large number of iron-ore deposits in western Labrador and northeastern Quebec. In 1915, Wilfred Thibaudeau surveyed the Labrador Plateau and engineered a channel scheme which could be used to divert the water from the river before it arrived at the falls. The scheme would use the natural capacity of the basin, thereby eliminating the need for the construction of massive dams.
In 1947, Commander G.H. Desbarats, under the direction of the Newfoundland Government, completed a preliminary survey that confirmed Thibaudeau's findings. However development did not proceed due to severals reasons:
- the inhospitable terrain
- severe climatic conditions
- geographic remoteness
- long distance transmission requirement
- the lack of markets for such a large block of power
In August, 1949, Joseph R. Smallwood, Premier of Newfoundland, had the opportunity to see Grand Falls (Churchill Falls) for the first time and it became his obsession to turn the roaring falls into a hydroelectric plant. In 1953 British Newfoundland Corporation (Brinco) was formed to do extensive exploration of the untapped water and mineral resources. With the development of the iron-ore mines in western Labrador and the construction of the Quebec North Shore and Labrador Railway (1954), development of Churchill Falls as a power source was feasible.
After years of planning, the project was officially started on July 17, 1967. The machine hall of the power facility at Churchill Falls was hollowed out of solid rock, close to 1,000 feet underground. Its final proportions are huge: in height it equals a 15-storey building, its length is three times that of a football field. When completed, it housed 11 generating units, which collectively have the capacity to generate 5,428 MW (more than 7,000,000 horsepower). Water would be contained in the reservoir not by a large dam, but by a series of 88 dykes that total 64 km (40 miles) in length.
Once all the dykes were in place it provided a vast storage area which later became known as Smallwood Reservoir. This reservoir covers 5,698 km² (2,200 miles²) and provides storage area for more than 1,000-billion ft³ (28 million m³) of water.
The drainage area for the Churchill River includes much of western and central Labrador. Ossokmanuan Reservoir which was originally developed as part of the Twin Falls Power System also drains into this system. Churchill River's natural drainage area covers over 60,347 km² (23,300 miles²). Once Orma and Sail lakes' outlets were dyked, it added another 11,396 km² (4,400 miles²) of drainage for a total of 71,743 km² (26,700 miles²). This makes the drainage area larger than the Republic of Ireland. Studies showed this drainage area collected 41 cm (16 in) of rainfall plus 391cm (12.8 ft) of snowfall annually equaling 12.5 miles³ (52 km³) of water per year; more than enough to meet the project's needs. Construction came to fruition on December 6, 1971, when Churchill Falls went into full-time production.
Project Facts
- Churchill Falls has the largest hydroelectric-generating capacity in North America (5,248 MW installed, expandable to 9,252 MW).
- Churchill Falls is the largest underground power station in the world.
- The powerhouse is 296 m (972 ft) long, up to 25 m (81 ft) wide and 47 m (154 ft) from the bottom to the top. The height would be equivalent to a 15 story building, as long as 3 football fields and is hollowed from solid granite. To strengthen walls and ceiling, more then 11,000 rock bolts (steel rods 5-6m (15 to 25 ft) long) were used in the three major chambers.
- To move the 1.9 million m³ (2.3 million yards³) of rock that was excavated from the underground caverns, it required 2,267,962 kg (5 million pounds) of explosives. This material was used in roads, building the town site, and as dyke material.
- The turbine wheels are cast of stainless steel and weigh 80 tons which is a world record for the largest stainless steel casting ever made.
- During construction, 663,000 tonnes of material, equipment and fuel were moved to the site.
- The natural catchment area for the Churchill River covers over 60,347 km² (23,300 miles²).
- By diverting the water from the Ossokmanuan Reservoir the total catchment area became 71,743 km² (26,700 miles²).
- Total natural drop of the water starting at Ashuanipi Lake and ending at Lake Melville is 528m (1,735 ft). As a comparison, the water starting 32 km (20 miles) upriver until it enters the power plant drops over 300 m (1,000 ft).
- There is no big dam associated with this hydropower plant. There are 88 dykes to contain the reservoir, the longest is 6.1 km (3.8 miles) and the highest is 36 m (117 ft). The total length of all dykes is 64 km (40 miles) and contains 22 million cubic m (26 million cubic yards) of embankment material.
- After five years of non-stop field work by approximately 6,300 workers and costing $950,000,000 (1970) construction culminated on December 6, 1971 when the first two generating units began delivering power, five months and three weeks ahead of schedule.
- Currently Churchill Falls makes almost 1% of the world's hydroelectric power.
- Newfoundland and Labrador recently announced a call to develop the Lower Churchill Project. This is, in fact, a number of small projects which includes a 2,100 MW dam at Gull Island, a 824 MW dam at Muskrat Falls, 1,000 MW upgrade to the existing facility at Churchill Falls. This would increase the present power production capability by an extra 4,000 MW for a total of 9,252 MW.
Specifications and statistics
Power station
| Annual energy output | 35,000 GWh |
| Station generating output | 5,428 MW |
| Number of generating units | 11 |
| Net head | 312.4 m |
| Maximum tailrace discharge | 1,387.52 m³/s |
| Turbines | 11 × vertical Francis type, 200 rpm |
| Generators | 11 × 15 kV, 526,315 kva |
| Transformers | 11 × 14.75 kV/240 kV, rated at 5,500 MVA |
Civil engineering
| Powerhouse | 296 m length, 25 m width, 47 m height, 310 m below ground |
| Tailrace tunnels | 2 × 1,691 m, 14 m width, 19 m height |
| Penstocks | 11 × 427 m length, 6.1 m diameter |
| Cable shafts | 11 × 2.13 m diameter, 263 m deep |
| Dykes | 88; 64.4 km total length, 9 m average height, 36 m maximum height |
| Reservoirs | 6,988 km² area; 32,670,000,000 m³ active storage |
| Total Catchment area | 71,743 km² |
See also
External links
- Churchill Falls Hydroelectric project (http://ieee.ca/millennium/churchill/cf_home.html)
Categories: Newfoundland and Labrador geography | Waterfalls of Canada | Historic civil engineering landmarks
