Great Slave Lake

Great Slave Lake
Great Slave Lake and Lake Athabasca
Coordinates	61°40′N 114°00′W
Lake type	remnant of a vast glacial lake
Primary sources	Hay River, Slave River
Primary outflows	Mackenzie River
Catchment area	985,300 km² (380,600 sq mi)
Basin countries	Canada
Max length	480 km (298 mi)
Max width	109 km (68 mi)
Surface area	28,400 km² (11,000 sq mi)
Max depth	614 m (2,015 ft)
Water volume	2,090 km³ (501.7 cu mi, 1.694 billion acre feet)
Surface elevation	156 m (512 ft)

Mackenzie River drainage basin showing Great Slave Lake's position in the Western Canadian Arctic

Great Slave Lake (French: Grand lac des Esclaves) is the second-largest lake in the Northwest Territories of Canada (behind Great Bear Lake), the deepest lake in North America at 614 m (2,015 ft), and the ninth-largest lake in the world. It is 480 km (298 mi) long and 19 to 109 km (12 to 68 mi) wide. It covers an area of 28,400 km² (11,000 sq mi) in the southern part of the territory. Its volume is 2,090 km³ (501.7 cu mi,1.694 billion  acre feet). The lake was named for the Slavey North American Indians.

The East Arm of Great Slave Lake is filled with islands. The Pethei Peninsula separates the East Arm into McLeod Bay in the north and Christie Bay in the south. The only community in the East Arm is Lutselk'e, a hamlet of about 350 people, largely Chipewyan aboriginals of the Dene Nation.

Geography

Canada's Great Plains stretch from the border with the United States to the Arctic Ocean, an area that accounts for 18 percent of Canada's land area. The plains are dominated by two river systems, the Saskatchewan (which flows west to east) and the Mackenzie, which flows past a series of lakes—Athabaska, Great Slave, and Great Bear—north to the Arctic Ocean.

The Hay and Slave Rivers are the chief tributaries of Great Slave lake. It is drained by the Mackenzie River. Though the western shore is forested, the east shore and northern arm are tundra-like. The southern and eastern shores reach the edge of the Canadian Shield, a region of rocks that are among the oldest on earth and hence are worn down, appearing barren though it is rich in minerals. Along with other lakes such as the Great Bear and Athabasca, Great Slave is a remnant of a vast post-glacial lake. The early settlements on the shores of Great Slave Lake were all originally Hudson's Bay Company posts. The fur trade dominated the economy almost to WWII. In the 1930s, the gold rush was in full swing and the small town of Yellowknife quickly sprouted into a full-blown shantytown. Some prospectors made millions - many others lost everything. Recreation activities abound in summer and in winter - hiking, camping, sport and ice-fishing are all popular. In March, visitors enjoy the Caribou Festival and the Championship Dog Derby.

Wildlife

With its ability to prepare itself for long, cold winters by consuming huge quantities of aquatic insects, snails, small fish and fish eggs, and to survive for up to 8 months under several metres of ice, the arctic grayling is well adapted to the lakes and rivers of northern Canada. In the Northwest Territories, the grayling is common in the Mackenzie, Coppermine, Anderson, Thelon and Back River drainages; in Great Slave Lake, it is likely to be found along shorelines and in shallower bays.

But wood bison are taller, heavier and longer-legged than plains bison (3.8 metres in length, 1.8 metres tall, 500 –1,000 kilograms in weight). They have a more pronounced shoulder hump, and a less developed beard than plains bison.

• Wood bison roam less than plains bison. They move only short distances between open meadows and surrounding forests.

• Like plains bison, wood bison are herbivores. They feed on grasses, sedges, willow leaves and twigs. In winter, they find food by swinging their massive heads from side to side to sweep the snow away.

The Mackenzie Bison Sanctuary’s population of about 2,000 wood bison is just a small fraction of the almost 200,000 shaggy, bearded beasts that once ranged throughout northern Alberta, northeastern British Columbia, southern Yukon, and the southwestern Northwest Territories. But it is a vast increase from the wood bison’s 1891 population low of 200 - 250 animals that resulted from years of over-hunting during the 18th and 19th centuries.

Today, the Mackenzie Bison Sanctuary, covering 10,000 square kilometres on the west side of Great Slave Lake, contains the world’s largest wild wood bison herd, and represents the first successful transplant of healthy wood bison into historic range.

The foundation of the Mackenzie Sanctuary was established in 1963, after Canadian federal wildlife officers located a herd of pure, wild wood bison in the Nyarling River area of Wood Buffalo National Park, south of Great Slave Lake. The newly-identified herd was remarkably free of the tuberculosis and bovine brucellosis that had been introduced to Wood Buffalo when infected bison from Wainwright, Alberta were transplanted to the newly-created reserve during the 1920’s.

History

Archaeologists estimate that humans settled in Canada 20,000 years ago. After the glaciers retreated (between 14,000 and 7,000 years ago, people moved north behind them. They lived in small groups, hunting and fishing. Tools, weapons, clothing, and ceremonial objects were fashioned from materials at hand. Weapons included bows and arrows, stone-tipped lances, deadfall traps, and snares. Few areas in the north were suitable for agriculture, so the conflict over land that had erupted in the United States between Native Americans and settlers were largely avoided.

British fur trader Samuel Hearne explored the area in 1771 and crossed the frozen lake, which he initially named Lake Athapuscow (after an erroneous French speaker's pronunciation of Athapaska, the indigenous people). Alexander Mackenzie, a Montreal merchant, discovered a river route to the Arctic in 1789.

1771 – Samuel Hearne: If the answer is the latter, then we may never know precisely who it was that first saw the broad expanse of water that had long been known to the Dogrib, Slavey and Chipewyan peoples. But if we accept recorded history as our guide, the distinction of being the Great Slave’s European discoverer appears to belong to Samuel Hearne, who trudged, famished and frost-bitten, across the ice-bound lake in the winter of 1771. Hearne was returning from a harrowing and fruitless journey that had taken him from Hudson Bay to the Coppermine River and the Arctic Ocean in the company of his First Nations guide, Matonabbee.

1776 – Laurent Leroux and Cuthbert Grant: The next Great Slave visitors are thought to be Laurent Leroux and Cuthbert Grant, founders of competing trading posts at Fort Resolution on the lake’s south shore in 1786. Some accounts suggest that fur trader Peter Pond, the first European to cross the fabled Meythe Portage into Athabasca Country, journeyed himself to Fort Resolution, but it is more likely that Grant made the trip under Pond’s direction.

1789 – Alexander Mackenzie: Next to venture on to Great Slave Lake was the legendary Alexander Mackenzie, still in the early stages of his 1789 journey to the Arctic Ocean. Although it was June, Mackenzie and his crew – including his Chipewyan guide, “English Chief” – were forced to contend with freezing temperatures and lingering ice. After crossing the lake from the Slave River delta to the north shore, they wandered for weeks through western bays and inlets before finding the river outlet that would ultimately bear Mackenzie’s name – and prove to be his lasting disappointment.

1820 – John Franklin: Last among the great explorers of the Great Slave was John Franklin, in the company of George Back, Robert Hood and John Richardson, who used Fort Providence (now known as Old Fort Providence) on the lake’s north shore as a base for his 1820 expedition to the Arctic Coast. It was at Fort Providence that Franklin was joined by the Yellowknife chief, Akaitcho, and it was the far-flung fort that represented salvation for the surviving members of Franklin’s tragic first journey, in which 10 men lost their lives.

In the 1930s, gold was discovered there, which led to the establishment of Yellowknife, the territory's capital.

In 1967, an all-season highway was built around the lake, originally an extension of the Mackenzie Highway but now known as Highway 3.

On January 24, 1978, a Soviet Radar Ocean Reconnaissance Satellite, named Cosmos 954, built with an onboard nuclear reactor fell from orbit and landed in the lake. With all the ice and snow on the lake the satellite exploded on impact, causing its nuclear fuel to fall over the area. The nuclear fuel was picked up by a group called Operation Morning Light, formed with both American and Canadian members.

Environment

With its remote northern location, vast area of 28,568 square kilometres, small population of less than 20,000 people, and only a handful of heavy industries, Great Slave Lake is regarded as one of the most pristine water bodies in the world. Yet residents of Yellowknife, on Great Slave’s northern shore, cannot drink the lakewater. It has been polluted by the area’s mining industry, forcing the community to draw its drinking water from the Yellowknife River, 5 kilometres away from the city.

Arsenic Atmosphere: For several years, beginning in 1943, the “roasting” process that was used to remove gold from arsenopyrite rock sent arsenic trioxide and sulphur dioxide into the air. Pollution control devices installed during the 1950’s trapped arsenic dust, but arsenic contamination detected in Yellowknife drinking water during the 1970’s resulted in the movement of the domestic water supply intake from Great Slave Lake to the Yellowknife River.

The gold roasting process at the city’s Giant gold mine was discontinued in 1999, leaving 238,000 tonnes of highly toxic, water soluble arsenic trioxide dust, stored in 15 underground chambers a few hundred metres from Great Slave Lake. Although the storage vaults are contained in bedrock and sealed with concrete bulkheads, concerns remain about leaching of arsenic into groundwater. Surface water contamination from the Giant Mine’s tailing ponds may also pose a pollution problem.

Remediation: A joint long-term management strategy for the underground arsenic vaults is being formulated by the Canadian federal government and the current owner of the Giant Mine; options include freezing the arsenic in place, or extracting it and treating it as hazardous waste. zinc and lead are also mined in the area

General Information

Other towns around the lake include: Yellowknife, Fort Providence, Hay River and Fort Resolution. Its waters are extremely clear and deep (maximum depth more than 2,000 feet [600 metres]). The lake contains many islands and supports a fishing industry (trout and whitefish) based at the villages of Hay River and Gros Cap.

The lake is at least partially frozen during an average of eight months of the year. During winter, the ice is thick enough for semi-trailer trucks to pass over. Until 1967, when an all-season highway was built around the lake, goods were shipped across the ice to Yellowknife, located on the north shore. Goods and fuel are still shipped across frozen lakes up the winter road to the diamond mines located near the headwaters of the Coppermine River, Northwest Territories. A ferry is required to access Yellowknife during spring when the ice is not present in a solid sheet along Highway 3 where it crosses the Mackenzie River.

South of Great Slave Lake, in a remote comer of Wood Buffalo National Park, is the nesting site of a remnant flock of whooping cranes, discovered in 1954.

Sources and further reading

• Brown, Craig, ed. 2002. The Illustrated History of Canada. Toronto, Canada: Key Porter Books. ISBN 1552635082
• Bothwell, Robert. 2001. A Traveller's History of Canada. London: Cassell & Co. ISBN 1900624486
• Canada. (1981). Sailing directions, Great Slave Lake and Mackenzie River. Ottawa: Dept. of Fisheries and Oceans. ISBN 0660110229
• Gibson, J. J., Prowse, T. D., & Peters, D. L. (2006). Partitioning impacts of climate and regulation on water level variability in Great Slave Lake. Journal of Hydrology. 329 (1), 196.
• Hicks, F., Chen, X., & Andres, D. (1995). Effects of ice on the hydraulics of Mackenzie River at the outlet of Great Slave Lake, N.W.T.: A case study. Canadian Journal of Civil Engineering. Revue Canadienne De G̐ưenie Civil. 22 (1), 43.
• Kasten, H. (2004). The captain's course secrets of Great Slave Lake. Edmonton: H. Kasten. ISBN 097366410X
• Jenness, R. (1963). Great Slave Lake fishing industry. Ottawa: Northern Co-ordination and Research Centre. Dept. of Northern Affairs and National Resources.
• Keleher, J. J. (1972). Supplementary information regarding exploitation of Great Slave Lake salmonid community. Winnipeg: Fisheries Research Board, Freshwater Institute.
• Mason, J. A. (1946). Notes on the Indians of the Great Slave Lake area. New Haven: Published for the Department of Anthropology, Yale University, by the Yale University Press.
• Sirois, J., Fournier, M. A., & Kay, M. F. (1995). The colonial waterbirds of Great Slave Lake, Northwest Territories an annotated atlas. Ottawa, Ont: Canadian Wildlife Service. ISBN 0662238842

External Links

• [1] Great Canadian Lakes
• [2] Canadian Encyclopedia
• [3] Encyclopaedia Britannica online

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