Inkwilersee

The Inkwilersee is a small lake on the border of the Swiss municipalities Inkwil, Canton Bern, and Bolken, Canton Solothurn.

It is about 500 meters long and 300 meters wide, its average water level is at 461.2 m above sea level, the average depth is 2.9 m and it has a surface area of ​​about 10 hectares.

History

The lake is about 10 000 years. As the Burgäschisee is also the Inkwilersee a small, arising from kettle holes lake on the border between the cantons of Solothurn and Bern. Already during the lacustrine age there were numerous settlements on the lake shore. At various points, was discovered during excavations on found objects. In spring 2007, the stilt houses were examined ( only underwater) by divers. They found spear points and tools. The municipal boundary Bolken - Inkwil goes through the sea, and over the Inseli ( the larger of the small islands ). Earlier called Lake Bolkensee and belonged to the municipality Bolken. On both islands in the lake the remains of Bronze Age pile dwellings were discovered.

Location

In the midst of the lake there is an island near the maximum depth of 6 m. Is drained of Inkwilersee by Seebach, which flows about 5 km further north into the Aare. There is a footpath around the reeds of the lake. A few kilometers from the Inkwilersee is about twice as large Burgäschisee.

Ecology

Siltation

In a pilot project, the water lilies were mowed Inkwilersee in the period from 19 to 24 August 2002. With the harvest of the roses that siltation pond should be slows and therefore the life of the lake can be extended. It is feared the Cantonal Office for the Environment that the lake without measures could silt in about 150 years altogether. Appropriate approaches to prevent be developed. The water lilies were mowed with a special Weed Harvester ( sea cow ) and then transported to the shore ( Teichrosenverlad ). There were mowed around three quarters of the dough stock. The scope of the harvest was set so that the protection of animal and plant life was assured. On the banks of the water lilies were crushed with a chopper and prepared for transport. The water lilies were recycled by the company Kompogas AG for the production of renewable energy ( Kompogas ).

Lack of oxygen / fish kills

The Inkwilersee is a highly eutrophic lake, that is, it is rich in nutrients and low in oxygen. This had in the past variously means that there has been in long warm phases to acute hypoxia and associated fish kills -. Least end of August 2009 and again 2011, fire service and army had 2009 aerate the lake for several days with water fountains to the oxygen content again to increase. The shallow depth of Inkwilersees favors the rapid heating of the water, but enough to form a hypolimnion from. Fish kills as in August 2009 and 2011 can occur if during persistent warm phase using winds that resolve the stratification of the lake and mix the oxygen-poor deep water with the remaining water. In 2011, a portion of the fish are rescued by Fishing out with nets and suspension in the near Aare. Smaller fish were able to survive, which has been in fresh water taken from fire hydrants in the two small tributaries.