| Kootenay Lake[1] | |
|---|---|
 Kootenay Lake with Old Tom Mountain in the background | |
 Map of Kootenay Lake, British Columbia | |
![Kootenay Lake[1] is located in British Columbia](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aCanada_British_Columbia_relief_location_map.jpg) ![Kootenay Lake[1]](/image.pl?url=http%3a%2f%2fen.wikipedia.org%2f%2fupload.wikimedia.org%2fwikipedia%2fcommons%2fthumb%2f0%2f0c%2fRed_pog.svg%2f20px-Red_pog.svg.png&f=jpg&w=240) Kootenay Lake[1] | |
| Location | Kootenay region,British Columbia |
| Coordinates | 49°38′N116°55′W / 49.633°N 116.917°W /49.633; -116.917 |
| Primary inflows | Kootenay River |
| Primary outflows | Kootenay River |
| Basin countries | Canada |
| Max. length | 104 km (65 mi) |
| Max. width | 5 km (3.1 mi) |
| Average depth | west arm 10 m (33 ft), main lake 45 m (148 ft) |
| Max. depth | 150 m (490 ft) |
| Residence time | avg. 1.5 years |
| Surface elevation | 532 m (1,745 ft) |
| Settlements | Nelson, British Columbia |
Kootenay Lake is alake located inBritish Columbia, Canada. It is part of theKootenay River. The lake has been raised by theCorra Linn Dam and has a dike system at the southern end, which, along with industry in the 1950s–70s, has changed the ecosystem in and around the water. TheKootenay Lake ferry is a year-round toll-free ferry that crosses betweenKootenay Bay andBalfour. The lake is a popular summer tourist destination.[2]
Kootenay Lake is a long, narrow and deepfjord-like lake located between theSelkirk andPurcellmountain ranges in theKootenay region of British Columbia.[3][4] It is one of the largest lakes in British Columbia, at 104 km in length and 3–5 km in width.[1] It is, in part, a widening of theKootenay River, which in turn drains into theColumbia River system atCastlegar, British Columbia.[1]
Although oriented primarily in a north-south configuration, a western arm positioned roughly halfway up the length of the lake stretches 35 km to the City ofNelson.[5] The lake is 532m above sea level,[1] with the adjacent mountains rising up to a maximum of approximately 2700m.[3] The average residence for water in the lake is 1.5 years, although the west arm has a much faster rate of water replacement; about 3–4 days.[3]
Kootenay Lake was formed through rivererosion and, later,glaciation. The erosion began during the lateCretaceous until ice filled the resulting valley in thePleistocene.[4] When the valley was filled with ice,glaciers from the mountains (the Selkirks and Purcells) fed the valley's ice mass. The glacier that occupied what is now the west arm of Kootenay Lake flowed into the Kootenay ice mass. As the ice melted from this glacier, drainage flowed over an area near what is now Nelson, causing the west arm of the lake to drain toward the west. A largemoraine formed near what is now the large bend in the Kootenay River nearLibby, Montana. As ice melted, a lake formed behind the moraine and drained southward over top of it. The southerly drainage over the moraine eventually stopped and the Kootenay River began to follow its present course.[4]
Kootenay Lake is impounded by theCorra Lin Dam, some 30-35 miles downriver. Outflow rates there[6][7] are 104 m3/s (3,700 cu ft/s) (minimum discharge), 782 m3/s (27,600 cu ft/s)[6][7] (average discharge); 4,930 m3/s (174,000 cu ft/s) (maximum discharge).
Kootenay Lake is part of the traditional territory of theSinixt andKtunaxa peoples.[8] These native populations used the lake and associated river systems as part of their seasonal migration and trading routes.[4]
In 1958 theKootenay Lake Crossing, anelectrical power line, was built, running across the north arm of Kootenay Lake. It was destroyed in 1962 by protestors and rebuilt later that year.[9]
The lake originally seasonallyflooded an approximately 80 km longmarsh lying to the lake's south within theCreston Valley. However, this has now beendiked and converted to commercialagriculture. A smaller wetland area has been protected in this area.
In 1931,Corra Linn Dam was built at the outflow from Kootenay Lake, where it once again became a river.[10] The dam provides flood control and winter power generation by raising the normal water level by two meters. Just down river isBonnington Falls, today the site of severalhydroelectric dams. In 2003 the lake discharged 16.9 billion cubic metres of water. High water for that year was a normal 533 metres, the record is 537 metres in 1961.[11] In 1967 as part of theColumbia River Treaty theDuncan Dam was constructed above Kootenay Lake on theDuncan River, creating a 7,145 hectare reservoir for flow control.[12] Also part of the treatyLibby Dam in Montana was completed in 1975.
Kootenay Lake is populated with many species of fish, such asRainbow trout,Bull Trout,Burbot,Mountain Whitefish,White Sturgeon,Brook Trout,Largemouth Bass,Yellow Perch,Pumpkinseed sunfish andKokanee Salmon.[4]
There was a large decrease in the numbers of Kokanee in the west arm of the lake in the late 1970s. The salmon fishery was closed in 1980 and remains closed as of 2011. The reason for the decline is not known; possibilities include reduced numbers ofMysis relicta (which had been introduced as a food source for the Kokanee in 1949)[12][13] into the west arm due to the increased control of water levels, the disruption of rearing habitat due to recurringdrawdown of the lake, reduced productivity ofbenthos due to the reduction of the amount of nutrients into the lake (after the close of the fertilizer plant), overfishing in the 1960s to 1970s[4] or competition between the Mysis relicta and immature fish.[13] In 1990 the lake's southern Kokanee stocks neared extinction, and an experimental fertilizing program was started, with some success.[14][12]
Approximately 19,700 people live within 2.5 km (1.6 mi) of the Kootenay Lake shore; about 10,250 of those live in the City ofNelson.[3] The remaining are scattered among a number of small towns and villages:
In 1953 water quality in the lake was negatively affected when theCominco phosphate fertilizer plant on the Kootenay River atKimberley opened.[12] Large quantities ofphosphorus entered the Kootenay River; the cause ofcyanobacterial blooms from the 1950s until the early 1970s. This plant closed in 1973 eliminating these phosphates.[12] The construction of theLibby Dam on theKootenai River inMontana and the Duncan Dam 1967 on the Duncan River, combined to further reduce natural phosphorus levels in the lake from the recorded highs.[4]
The lake is crossed by theKootenay Lake ferry, a toll-free vehicular ferry operating between Balfour and Kootenay Bay. The ferry operates two boats in the summer and one during the winter.[15]
.svg)
