The dark blue line is the Kootenay River. The rivers end up forming a circle around the Selkirk and Purcell Ranges. The Kootenay goes south to cross the border then north west to cross the border again to join the Columbia which initially went north then south to cross the USA border after the confluence. Both rivers are basically following fault lines that have been eroded by glaciers and wind and water erosion.
The Kootenay River (Kootenai in USA) historically called the Flatbow has its headwaters over 100K from the Columbia Lake, the source of the Columbia River. The Kootenay comes within 1.5 K from the lake at Canal Flats and is only separated by a berm of soft material that is only about 11 feet high. During heavy flooding periods the two have joined. At Canal Flats the floor of the Rocky Mountain Trench floor is separated, as a result of faulting, so that one side tips downhill southward and at the same point tips downhill northward. Thus the Kootenay River flows south to cross the US border and the Columbia flows northward for about 200K towards Kinbasket Lake before it turns west then south.
During the ice age Glacial Lake Invermere stretched approximately 210K from just north of Golden to Skookumchuck. During this period, the Kootenay River flowed into Glacial Lake Invermere. Columbia Lake (9 miles long) is a remnant of that lake and its major source is thought to be springs and from the Kootenay River. Thus they share a heritage.
A coincidence is that the Columbia starts in a lake and the Kootenay has a major lake at its terminus just before the confluence. The Columbia Lake however is only 9 miles long with an average depth of 15 feet whereas Kootenay Lake is approximately 60 miles long with an average depth of 300 feet. Another similarity is that both Lakes resulted from glaciations. Kootenay Lake is a Fjord Lake which resulted from glacial deepening of the mountain sides whereas Columbia Lake is primarily from glacial run fluvial off.
Another similarity is that the man made dams created major lakes in both river systems. The Mica dam near the Columbia’s northern Big Bend expanded the small Kinbasket Lake which was named after the Shuswap leader Chief Kinbasket. The Libby dam on the USA side of the Kootenay created the Koocanusa Lake which straddles the border. Koocanusa is from the shortening the words KOOtenay, CANada and USA.
Schematic showing Columbia drainage basin
Some interesting elevations: Kootenay- 7,217’; Canal Flats- 2,665’; Kinbasket- 2,106’; Libby- 2,096’; Kootenay Lake- 1,745’; Confluence- 1,377’.
The Columbia River was named by Capt. Robert Gray in 1792 after his vessel the Columbia Rediviva. After some difficulty navigating the mouth of the river he went upstream about 12-15 miles. This adventure was used as the claim by the United States for the land of the Pacific Northwest. David Thompson from the North West Company travelled from near its source at Invermere to the mouth at Astoria in 1811 and became the first European to navigate the full length.
Ground zero is on Zuckerberg Island Heritage Park. While here observing the confluence take some time to enjoy the hiking trails along with a replica of a Salish pit house and a Russian Orthodox style chapel built by Andrew Zuckerberg over 60 years ago.
Acknowledgements to: B.C. Pearce (Geological Field Guide to The Southern Rocky Mountain Trench; E Swanson, College of the Rockies; Ben Gadd, Handbook of the Canadian Rockies; Wikipedia.
To log this Earthcache, please email the owner with the following: a) How did you access the Island? b) Describe the state of the water at the confluence, i.e. turbulent? c) If the Kootenay started 100 k from the start of the Columbia, why is it considered a tributary and not the main river? d) What is the biggest effect of the numerous dams? e) How is that these 2 rivers twice in almost the same parallels, can travel in opposite directions?
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