Lac de Gras

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Lac de Gras
Lac de Gras.jpg
Lac de Gras
Location Northwest Territories
Coordinates 64°30′N 110°30′W / 64.500°N 110.500°W / 64.500; -110.500Coordinates: 64°30′N 110°30′W / 64.500°N 110.500°W / 64.500; -110.500
Primary outflows Coppermine River
Basin countries Canada
Max. length 60 km (37 mi)
Max. width 16 km (9.9 mi)
Surface area 569 km2 (220 sq mi)
Max. depth 56 m (184 ft)
Shore length1 740 km (460 mi)
Surface elevation 396 m (1,299 ft)
References [1]
1 Shore length is not a well-defined measure.

Lac de Gras is a lake approximately 300 kilometres (190 mi) north east of Yellowknife, in the Northwest Territories of Canada. Lac de Gras was the centre of the diamond rush of the 1990s. There are three working diamond mines in the area, Diavik Diamond Mine, Ekati Diamond Mine, and Snap Lake Diamond Mine.[2][3] It was called Ekati by aboriginal peoples.

The lake is ultraoligotrophic but supports a slow-growing but stable population of some eight species of cold-water fishes, including round whitefish, cisco, and lake trout. Lake trout dominate the lake, both numerically and in terms of biomass.[4] Other native fish species include common whitefish, Arctic grayling, burbot, longnose sucker, and slimy sculpin.

Diavik Diamond Mines is conducting open-pit mining of kimberlite pipes using explosives near the lake.[4]

Lac de Gras' surface area is 56,910.8 ha (140,630 acres); the historical surface area was 57,107.2 ha (141,115 acres), about 196.4 ha larger than today. The subbasin area is 413,570 ha (1,022,000 acres) with the number of lakes smaller than 1 ha 3,487; 1-10 ha 2,080; 10-100 ha 663; and larger 100 ha 106, together with a total surface area of 135,035 ha (333,680 acres).[5]

Lac du Sauvage is a small lake that drains into Lac de Gras through a 45 m (148 ft) wide and 210 m (690 ft) long stream called the Narrows. The median flood peak discharge in the Narrows is 17.5 m3/s (620 cu ft/s) making it an important corridor for fish movements.[5]

See also[edit]


  1. ^ Atlas of Canada. "Rivers in Canada". Archived from the original on 10 April 2007. Retrieved 2015-03-17. 
  2. ^ Power, Patrick (9 January 2013). "Arctic Star identifies Diamond Targets for Drilling in the prolific Lac de Gras area, NWT Diamond Fields". Arctic Star Exploration. Archived from the original on 15 September 2013. 
  3. ^ Danielson, Vivian (11 July 2011). "Randy Turner: Reflections of a diamond industry pioneer". The Northern Miner. 
  4. ^ a b Faulkner, S. G.; Tonn, W. M.; Welz, M.; Schmitt, D. R. (2006). "Effects of explosives on incubating lake trout eggs in the Canadian Arctic" (PDF). North American Journal of Fisheries Management. 26 (4): 833–842. Retrieved 22 May 2016. 
  5. ^ a b Developer’s Assessment Report, Jay Project, Appendix 9A, Conceptual Offsetting Plan (PDF) (Report). Dominion Diamond Corporation. October 2014. Retrieved 22 May 2016.