Frame Lake
Frame Lake | |
---|---|
Seepage | |
Surface area | 84 hectares (210 acres)[2] |
Max. depth | 6.5 metres (21 ft)[2] |
Surface elevation | 186 metres (610 ft)[3] |
Frozen | Winter |
Islands | 5 |
Settlements | Yellowknife |
Frame Lake is located in
Formed by meltwater after the end of the Wisconsin glaciation 20,000 years ago, Frame has been an important part of Yellowknife's history. The Dene in the area used it as a fishing spot before European settlement. In the early years of the city's growth, gold mines nearby dumped tailings in it and sometimes sewage. Later, when the city's New Town, now its downtown section, was surveyed and developed nearby, Frame offered accessible swimming and boating opportunities.
However,
Some city residents have agitated for efforts to reclaim the lake so it will once again be a destination for swimmers, anglers and boaters in warm weather. To do so, it will be necessary to
Geography
Frame Lake is irregularly shaped, with a northern section and a southern section along a north-northeast to south-southwest axis approximately 1.4 kilometres (0.87 mi) long, connected by a narrower central passage midway along its length where a wide peninsula extends from the western shore and an arm extends roughly 500 metres (1,600 ft) to the east, curving northward. At their widest shorelines, both sections are roughly the same distance apart. Five small islands are located within the lake, three in the northern section and two in the southern section.[3] Its total surface area is 84 hectares (210 acres).[2]
The lake lies at an elevation of 186 metres (610 ft). Surrounding terrain is gently undulating, with some of the small hills nearby cresting as high as 207 metres (679 ft) and one of the islands rising to 197 metres (646 ft). Two unnamed streams drain into the lake south of the peninsula on the western side. The northerly of the two rises from
Surrounding terrain, as well as that of the islands, is primarily taiga forest, amid mostly bare outcrops of Canadian Shield bedrock typical of the Yellowknife area. Bare rock predominates on the shoreline, except for some shallow bays with weed beds.[2] On the eastern shore, near the southern end of the lake, is an overgrown sandy area called McNiven Beach,[6] after the city's first mayor.[8]
The developed areas of Yellowknife form a "V" around the lake. On the eastern side, and the southern shore of the arm, is New Town, the city's modern downtown.[9] Public buildings such as City Hall, the Royal Canadian Mounted Police's local headquarters, and the Canadian Forces Northern Area Headquarters Yellowknife are situated along the south side of the arm, their associated lawns coming almost to the edge of the lake.[10]
South of City Hall along the lake shore is Somba K'e Park,
At the south end, another residential neighborhood comes near the lake, after which a rocky area buffers Stanton Regional Hospital.[11] Commercial strip development along Old Airport Road also comes close, and the road itself runs alongside part of the lake's southwestern shore for 100 metres (330 ft).[12] After it curves away to the west, the northwestern side and northern end of the lake are all taiga and bedrock between Frame and nearby Robinson's Pond and Jackfish Lake, with just the trail alongside.[9]
Amid a park-like setting on the northeastern corner of the lake, and the northern shore of the western arm, stand two other large public buildings: the
History
Formed by the retreat of the glaciers at the end of the last Ice Age, Frame Lake remained a relatively pure lake even as the area was settled and modern development impinged on it. The closure of its only outlet around 1970, however, led swiftly to its decline and eutrophication. By the end of the 20th century it could no longer support fish and was not being used for primary recreational purposes. Attempts to revive it started in the 2010s.
Prehistory–1934: Before European settlement
Like many of the lakes in the
Human use of the lake began with the Dene, the First Nations in the region, whose ancestors settled there around 7,500 years ago.[14] The Yellowknife band, who would later give their name to the city, found the lake abundant with pike, suckers and whitefish. While they did not settle on its shores, they established a fishing camp there.[15][16]
1934–1992: Growth years and lake decline
The descendants of European settlers began coming to the area of the lake in the early 20th century, first using it as a staging area for
External image | |
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1967 picture of swimming facilities at McNiven Beach |
Yellowknife's growth was briefly interrupted by
At the same time, runoff from storms carried increasingly nutrient-rich waters into the lake. In colder months when the lake surface was not frozen over, the city dumped plowed snow into the lake, adding even more nutrients.[16] Sewage dumped into nearby Niven Lake, heavily used for that purpose for almost 35 years of Yellowknife's postwar growth, may also have flowed into Frame, offering more nutrients.[17]
By the early 1970s the lake's decline had been noted. A later study by the earth science department at Carleton University concluded that the 1970 construction of the causeway across the end of the lake's eastern arm was the "tipping point" for Frame Lake. It cut off the stream between it and Niven Lake to the north, the only outlet the lake had had during human habitation of the area. With the lack of water throughput, nutrient levels in the water column rose, nurturing aquatic plants during the summertime. In the winter, however, when the lake froze over and snow cover blocked much of the limited sunlight available,[Note 2] those same plants died off for lack of ability to photosynthesize. The decomposed plant matter began accumulating on the lake floor, steadily deoxygenating its waters.[16]
In a 1973 limnological study of seven lakes in the Yellowknife area, including Frame, for a possible experimental fishery, scientists from the Fisheries Research Board noted that Frame was the only one in which they were unable to catch any fish for study.[18] Over the preceding winter, they also observed that the lake had "become rapidly anoxic".[19]
As the lake declined, development came closer. Yellowknife built its current city hall by the lake edge in 1975, and the Prince of Wales Northern Heritage Centre, the territorial museum, followed nearby four years later. Sometime later that decade, the number of swimmers at McNiven Beach declined sufficiently for the city to remove the facilities there, as the beach itself began to grow over with grass.[17]
Residents were still swimming and boating in the lake in the early 1980s, but in smaller numbers. Some were scared off by reports of
1993–present: Reclamation attempts
The
In 2007, a conservation report prepared for the city named Frame Lake its top priority and suggested enacting special nature-preservation zoning to protect it.[21] During the following decade, residents began to rediscover Frame Lake. "As a city, we've largely disengaged from this little jewel in our midst", wrote Matthew Mallon in YK_Edge, a local weekly newspaper. Newer residents, he said, were incredulous at his recollections of swimming and sailing on the lake in his childhood.[17] In 2013 another local resident organized a Canada Day cleanup and swim in the lake, saying concerns about arsenic and leeches in the water were exaggerated.[8]
The Carleton study carried out under a grant from Tides Canada[15] and the Royal Bank of Canada in 2015 established that the lake had declined more precipitously since 1970, and described how. It will continue to measure the degradation of the lake on an annual basis to form a basis for policy recommendations to revitalize the lake.[16] Currently researchers believe that either dredging rotten sediments off the lake bottom or aeration would best restore the water quality of the lake's early years.[17]
Geology
The lake is mostly underlain by a mix of
Two local faults run across the south end of the lake. The stream from Robinson's Pond runs along the Pud Fault, which continues across the lakebed to McNiven Beach. At the south end is the larger Kam Fault, which when it was active had the same potential for earthquakes as the San Andreas Fault in the U.S. state of California. It divides the basalt from an area of lighter granite and granodiorite between the lake and the hospital.[6]
There are also visible signs of the lake's glacial origins. Just south of Somba K'e Park on the east shore, the rock has striations and scour marks in the northeast-to-southwest direction of the glaciers' advance. The fine sand on the lake bed is also glacial residue.[6] In some areas around the lake edge, the ground is underlain by permafrost at an average depth of 15 metres (49 ft).[20]
Where soil exists around the lake, it is mostly silt and clay as opposed to the sand of neighboring New Town. It does not support buildings well, nor does it give way to bedrock at a uniform depth. The military building and visitor's centre both encountered construction difficulties due to this.[20]
Hydrology
There have been two significant periods of study on Frame Lake. One, in the early 1970s, looked at its water. The others, in the mid-2010s, examined the sediments to determine how the lake had reached the point it had by then.
1970s study
In 1971, just after what a later study would identify as the point when the lake's eutrophication began in earnest, M.C. Healey and W.L. Woodall, two researchers from the Fisheries Research Board of Canada, considered Frame in a limnological study of seven lakes in and around Yellowknife that their agency was considering as sites for an experimental fishery. Among the others studied were the larger Kam Lake to the south, and five others outside city limits. Their analysis, published in 1973, showed that while Frame's water quality was still good enough to support the recreational use that was still occurring, there were already some signs of decline.
Chemical analysis of the water showed similarities to Kam Lake. Like the larger lake, it had a notably alkaline
"Frame Lake had the most peculiar species assemblage for the region", the two wrote of the results of their
They did not find any fish, the only one of the seven lakes where this was the case. Frame nevertheless recorded the highest biomass count of the seven lakes, 7.32 grams of dry weight per square meter of bed, more than three times the second highest reading, on the second of two sampling periods in summer 1971. At the same time, that biomass had the lowest ash content of any of the sampled lakes as well.[18]
2010s studies
Healey and Woodall were not able to analyze any sediments underneath more than one meter (3.3 ft) of water because the particles were too fine for the Ekman dredge sifter that they used.[2] In 2013 Sarah Shenstone-Harris, a University of Toronto undergraduate interning at the school's Centre for Global Climate Science, was able to analyze the sediments. She looked to the diatoms in them to try to see if climate change had played a role in the lake's decline. If so, she also asked, when did that change occur, and was it possible to restore the lake to a level of water quality comparable to what it had been prior to the establishment of Yellowknife?[27]
Shenstone-Harris started from the observation that
Due to diatom dissolution at the lowest level of the sediments taken, Shenstone-Harris was unable to establish data for any years earlier than 1943, making it impossible to set the desired baseline for a pre-settlement Frame Lake. However, she was able to establish that the lake had always been at a high
It was not clear to Shenstone-Harris that that event had been the result of climate change. From 1956 to 1992, the last year records were kept, ice cover on the lake remained relatively stable throughout the winter, yet the amount of Cyclotella and Fragliaria, two
In 2015 the Carleton team was able to examine the sediments. They found that the period between the late 1940s and 1970 added a half-meter (20 in) of sediment to the bottom of the lake, the most of any lake in the region. Above it, the 10 centimetres (3.9 in) of sediment postdating the causeway was "black, sulfurous smelling and characterized by very high levels of metals, particularly arsenic".[16] These are consistent with the patches of sediment Mallon recalled from his youthful recreation on the lake in his 2015 article, noting that "I can still vividly feel the stuff's gloopy embrace on my feet" (although an accompanying sidebar by another reporter suggested that the sediments may be the result of sewage back-flushed from Niven Lake).[17]
See also
Notes
- ^ While the word "endorheic" has not been used to describe the lake, Woodall and Healey described it as having only seepage as its outflow, and later sources (such as Carleton) note that the 1970s construction of the causeway blocked the only outlet.
- ^ Due to its high northern latitude, Yellowknife receives as little as four hours of daylight during the weeks around the winter solstice.
References
- ^ a b "Yellowknife Heritage Map" (PDF). City of Yellowknife. Retrieved October 10, 2015.
- ^ a b c d e f Healey, M.C.; Woodall, W.L. (1973). "Technical report No. 407: Limnological Surveys of Seven Lakes Near Yellowknife, Northwest Territories" (PDF). Fisheries Research Board of Canada. p. 3. Retrieved October 5, 2015.
- ^ a b The Atlas of Canada (Map). 1:17,500. Cartography by Natural Resources Canada. Government of Canada. Retrieved October 6, 2015.
- ^ a b Wolfe, Stephen, ed. (1998). "Living with Frozen Ground: A Field Guide to Permafrost in Yellowknife, Northwest Territories (Geological Survey of Canada, Miscellaneous Report 64)" (PDF). Natural Resources Canada. p. 43. Retrieved October 6, 2015.
- ^ a b c "Yellowknife's Frame Lake oxygen levels too low for fish, say scientists". Canadian Broadcasting Corporation (CBC). July 13, 2015. Retrieved October 6, 2015.
- ^ a b c d e f "Frame Lake Trail Geological Guide" (PDF). Northern Frontier Visitor's Centre. 2005. Retrieved October 6, 2015.
- ^ The Atlas of Canada (Map). 1:17,500. Cartography by Natural Resources Canada. Government of Canada. Retrieved October 6, 2015.
- ^ a b c Punter, Cody (July 10, 2013). "McNiven Beach makes waves". Northern News Services. Retrieved October 7, 2015.
- ^ a b ACME Mapper (Map). Cartography by Google Maps. ACME Laboratories. Retrieved October 7, 2015.
- ^ ACME Mapper (Map). Cartography by Google Maps. ACME Laboratories. Retrieved October 7, 2015.
- ^ a b ACME Mapper (Map). Cartography by Google Maps. ACME Laboratories. Retrieved October 7, 2015.
- ^ ACME Mapper (Map). Cartography by Google Maps. ACME Laboratories. Retrieved October 7, 2015.
- ^ ACME Mapper (Map). Cartography by Google Maps. ACME Laboratories. Retrieved October 7, 2015.
- ^ Frozen Ground, 5
- ^ a b "Frame Lake Rehabilitation Project receives RBC Blue Water Fund support". Tides Canada. July 13, 2015. Retrieved October 7, 2015.
- ^ a b c d e f "Who Killed Frame Lake?". Carleton University. July 17, 2015. Retrieved October 8, 2015.
- ^ a b c d e f g Mallon, Matthew; Rendell, Mark (July 9, 2015). "Saving Frame Lake: Bringing Fishing and Boating Back to the Heart of YK". Edge_YK. Retrieved October 8, 2015.
- ^ a b Woodall and Healey, 14.
- ^ a b Woodall and Healey, 6.
- ^ a b c Frozen Ground, 35
- ^ Johnson, Adam (July 13, 2007). "Environmental top 40". Northern News Services. Retrieved October 11, 2015.
- ^ Woodall and Healey, 4
- ^ a b Woodall and Healey, 7
- ^ Woodall and Healey, 8
- ^ Woodall and Healey, 9
- ^ Woodall and Healey, 11
- ^ a b c d Shenstone-Harris, Sarah (2013). "Using Lake Sediments to Track Environmental Change in a Subarctic, Urban Lake" (PDF). University of Toronto. Retrieved October 13, 2015.
External links
- Media related to Frame Lake at Wikimedia Commons