Lake Trekanten
| Trekanten | |
|---|---|
View from Nybohov
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| Coordinates | Coordinates: |
| Primary outflows | Liljeholmsviken, Lake Mälaren |
| Catchment area | 60 ha (150 acres) |
| Basin countries | Sweden |
| Surface area | 13.5 ha (33 acres) |
| Average depth | 4.3 m (14 ft) |
| Max. depth | 7.0 m (23.0 ft) |
| Water volume | 570,000 m3 (460 acre·ft) |
| Residence time | 3 years |
| Shore length1 | 1,690 m (5,540 ft) |
| Surface elevation | 0.67 m (2 ft 2 in) |
| Settlements | Gröndal, Liljeholmen |
| References | |
| 1 Shore length is not a well-defined measure. | |
Trekanten (English: The Triangle) is a small lake in southern-central , Sweden.
With a small drainage area with no major feeders, Trekanten is located in a park furnished with an artificial bathing beach and various planted-out fish species. In the early 1980s, potable water was begun to be poured into the lake while water from the bottom of the lake was pumped out, operations resulting in a significant reduction in levels of phosphorus but which failed to affect levels of nutrients and oxygen depletion in bottom layers. Levels of lead and copper are among the highest documented in any lake in Stockholm. Whilst the lake flora and fauna is roughly representative for Stockholm, the lake forms a natural link between the bays Årstaviken and Vinterviken.
Along the shores of the lake is a park created on a flat terrain. Leading up to Nybohov on the southern side of the lake is a fault bluff with pines and deciduous trees, including hazel. On the eastern shore is a bathe next to the Liljeholmen metro station, a bus terminal, the light rail Tvärbanan, newly added flats, and some older buildings. Several residential areas surround the lake, including Gröndal.
About 30% of the catchment area is settled land and two major traffic routes passes through the area.
In an old industrial area north of the lake is a timber trade, the only remaining polluting operation in the catchment area. About 60 kg of phosphorus is brought to the lake annually, of which more than half is released from lake sediments and the rest is derived from surface runoff (also contributing some 260 kg of nitrogen). Historically, the lake was flanked by small scale industries such as tanneries, dye, and creosote works and until the early 1960s sewage and overflow water was guided into the lake. During the past 20 years, however, airing of bottom layers coupled with addition of potable water have improved the state of the lake. While the affected terrain has been restored since the operations were discontinued, in 1997 low levels of arsenic and increased levels of DDT were documented.
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Wikipedia