Lac Lioson
| Lac Lioson | ||
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| Geographical location | Canton of Vaud | |
| Drain | Hongrin | |
| Location close to the shore | Les Mosses | |
| Data | ||
| Coordinates | 576150 / 137272 | |
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| Altitude above sea level | 1848 m above sea level M. | |
| surface | 7 ha | |
| Maximum depth | 25 m | |
The Lac Lioson is a mountain lake of Vaud Alps in western Switzerland . It is located near the Col des Mosses in the Ormont-Dessous municipality .
etymology
The name lioson probably comes from the words lieu (vernacular liu , French for place) and son (from French: sommet , summit) and denotes the highest pastures on which the cattle were last driven in the summer. The name was first recorded as Lyuson in 1247.
geography
Lac Lioson is of glacial origin and is located in the Vaudois Pre-Alps at 1,848 meters north of the Châtillon and the Pic Chaussy , from whose foothills it is surrounded. Politically, it is in the Ormont-Dessous municipality in the canton of Vaud . The Hongrin rises from the lake , a left tributary of the Saane , which drains into the North Sea via the Aare and Rhine . The small meltwater lakes in the neighboring Kar Vers les Lacs are already draining towards the Rhône and the Mediterranean. This means that the lake is located directly on the Rhine-Rhône watershed.
Lac Lioson is around seven hectares with a maximum depth of 25 meters. Its volume is 846,000 m 3 and the mean depth is therefore 13.6 meters. Its catchment area extends over 1.5 km² and consists mainly of bare earth (28%), grassy areas (27%) and agricultural areas (30%). The remaining 15 percent make up forest (14%) and built-up area (1%).
physical and chemical properties
Due to its location at an altitude of 1,848 meters, the lake is ice-covered for about seven months of the year (typically from November to June). Due to the density anomaly of the water, the lake is stably stratified at this time with water temperatures of ~ 3 ° C in the deep water and lighter water around 0 ° C in the epilimnion . Even in summer, a stable stratification forms with water temperatures of around 12 ° C in the epilimnion and 3 ° C in the deepest layer. As a result, the lake mixes twice a year: at the end of the ice-covered period and at the end of summer, so that it is counted among the dimictic lakes.
The viewing depth , measured with the Secchi lens , is around 7.5 meters in summer. As early as 1923, a Secchi depth of 7 meters was measured in the summer. The nutrient concentrations are relatively low (on average 13 mg L −1 phosphorus), which is why Lac Lioson is counted among the oligotrophic lakes. Due to the stable stratification in winter and summer, the oxygen content in the deepest water layers drops regularly into the hypoxic area. Despite the low nutrient content, the proportion of organic carbon in the upper sediment layers is relatively high at 11%, which is due to the low temperature and low oxygen concentrations, which slow down the breakdown of organic substances.
Biological properties
Investigations at depths of 15 and 25 m revealed a macrofauna consisting exclusively of oligochaeta and insect larvae, whereby the deepest area of the lake was five times less species-rich than the area of medium depth, the number of individuals was even almost ten times lower (10,833 ± 6982 ind. m −2 at a depth of 15 m compared to only 1,146 ± 1273 ind.m −2 at a depth of 25 m). Especially in the deepest range, the observations, including the presence of Tubifex tubifex , indicate a dystrophic state with a medium nutrient content and a high proportion of humic acids .
There are relatively few aquatic plants in the lake, which can be attributed to the nature of the sediment and the steep slope of the shore zone. A total of five species of aquatic plants and five other species colonizing the bank area were observed. Four of them are on the red list of endangered species.
Originally there were no fish in the lake, but it has been populated with different species. In 1824 not a single fish was found, although trout was said to have been used earlier. There were already brown trout in 1923, but it is not known when they came into the lake. Since the 1960s, lake and brook trout , American char , brook trout and rainbow trout have been used regularly by the canton of Vaud , and since 1984 only brook and rainbow trout have been used. Although only two fish species are regularly used, six species are still observed (in addition to the ones mentioned above, the brook loach ). The arctic char is the most common species because it only grows slightly in the alpine Lac Lioson and is therefore not very popular with fishermen.
use
The lake is used for fishing and in winter for ice diving. Its clear water provides a habitat for char , trout and rainbow trout , among other things . There is a restaurant on the bank with overnight accommodation. The lake can be reached on foot from Col des Mosses in around an hour.
Individual evidence
- ↑ a b c d B. Müller, A. Lotter, M. Sturm and A. Ammann (1998): Influence of catchment quality and altitude on the water and sediment composition of 68 small lakes in Central Europe. Aquatic Science 60, pp. 316-337.
- ^ Henri Jaccard: Essai de toponymie. Origine des noms de lieux habités et des lieux-dits de la Suisse romande. Lausanne, Bridel, 1906. pp. 234f.
- ↑ a b c d e f g Brigitte Lods-Crozet, Pierre-Alain Chevalley and Andrés Strawczynski: Suivi écologique du Lac Lioson, campagne 2012. Division Protection des eaux, Direction générale de l'environnement, Canton de Vaud 2014.
- ↑ a b Emile André (1923): Le lac Lioson et sa faune. Bulletin de la Société vaudoise des Sciences naturelles 55, pp. 22-29.
- ↑ Brigitte Lods-Crozet, Olivier Reymond and Andrés Strawczynski (2008): Evaluation de l'état écologique de deux lacs sub-alpins suisses (canton de Vaud) . Bulletin de la Société vaudoise des Sciences naturelles 91, pp. 157-173.
- ↑ a b Jean-François Rubin (1991): L'omble chevalier, Salvelinus alpinus (L.), dans le Lac Lioson (Suisse) . Bulletin de la Société vaudoise des Sciences naturelles 80, pp. 419-434.
- ^ Site de plongée du Lac Lioson. Le Scaph, December 30, 2014, accessed October 5, 2015 .
- ↑ Lac Lioson on nature-peche.com. nature-pêche, accessed October 5, 2015 .
- ^ Mass camp at "Lac Lioson". Leysin Tourisme, accessed October 5, 2015 .