Brennsee

Brennsee or Feldsee is a lake in Gegendtal in Carinthia. It is located on the territory of the municipality Feld am See. The lake is used for bathing.

Geography

The Feldsee lies between the slopes of Mirnock and Wöllaner Nock, which plunge down towards the lake, in the Talfurche of Gegendtals. The slopes of the Mirnock is covered by forest, the sun-exposed slopes in the north of the lake carry mainly pastures and some large farms.

Hydrology and Ecology

The inflow of the lake is carried out through the flow of groundwater, and on the other from the north on several small tributaries. The lake outflow empties into the Kleinkirchheimer stream which then flows as Riegersbach in the Millstaetter lake. The average discharge is 80 l / s The lake has a water renewal time of about 2.5 years.

The lake is holomiktisch and has a distinct stratification in summer. The surface temperature in summer rises to 23 ° C.

The lake water has a very low lime content, the lake is one of the kalkärmsten Talseen in Carinthia.

The lake has a catchment area of 8.3 km ².

The settlements in the catchment area were connected in 1976 to 1981 to the sewer system, the wastewater is cleaned since then in the sewage treatment plant the wastewater association lake Millstaetter in Spittal an der Drau. The wastewater or slurry application from the farms but from about 1975 led to a strong eutrophication of the lake. As of 1985, a strong weed near the shore with Elodea canadensis, Myriophyllum spicatum and observed several species of the genus Potamogeton. In addition, the algae grew strong, there has also been a regular blue-green algae blooms. The water was very turbid, there was also foaming at the surface. Mechanical Entkrautung was ineffective. In 1991, a restructuring plan was created. 1992, a deep-water ventilation was installed.

The refurbishment measures, the lake was assessed in 2009 from a hygienic point of view as well, the trophic status was classified as a low mesotrophic.

The lake has 15 species of fish, the annual yield is 30 to 40 kg / ha. This rather high value is achieved by the strong fish stock and the rich underwater plant stand. The large part of the yield is based on the stock fish pike (Esox lucius) and carp (Cyprinus carpio). Pike, catfish ( Silurus glanis ) and perch (Perca fluviatilis) have good stocks. Among the Fried fish roach ( Rutilus rutilus ), rudd ( Scardinius erythrophthalmus ) and arbor dominate ( Alburnus alburnus ).

The noble crayfish (Astacus astacus ) is extinct in the 1970s in the lake. Since 1992, each year approximately 1,000 copies are used with the aim to re-establish a stock in the lake.