Keutschacher See

The Keutschacher See (Slovene: Hodiško Jezero ) is located south of the Wörthersee in Carinthia, Austria. With an area of 1.32 km ², it is the sixth largest in the Carinthian lakes. 1864 here a lake-dwelling was discovered from the Neolithic period. On the south shore of the lake there are two naturist campsites.

Geography

The lake is located in Keutschacher Seental in the Sattnitz, which owes its origin to a side branch of the Draugletschers. This has reshaped the tectonically preformed Talfurche. The lake was much larger than today in the past, this is from the extensive bog areas east and north of the lake can be seen.

The lake has an elongated oval shape. To the west lies a bay, here open the inflows. To the east is a narrow peninsula that juts about 400 m into the lake. In the middle of the lake is a shoal where the water is only 1.6 m deep. Peninsula as part of shoal are rocky ridges which sweep in southwest-northeast direction under the seabed. Its maximum depth of 15.6 m reaches of the lake near the shoal in the middle of the lake. To the west of the lake silting areas close to that range with their bogs to Hafnersee. This is also a small pond, the so-called bog pond. The bog is passed with sedges and reeds.

The catchment area of the lake covers 28.4 km ². Of these, approximately 54% forest, 30 % agricultural land, 6% water, the rest are residential and recreational areas.

Hydrology and Ecology

A tributary of the lake is the Keutschacher Rakoza or Rodabach flowing through the Hafnersee. The bogs in the east of the lake drained by a small stream ( Moorbach ) also in the Keutschacher lake, but the more eastern parts of the Seentals drain towards the east. From the Sattnitz ago of Weissbach and two unnamed streams flow a.

The lake warms rapidly in spring and reaches in the middle of the lake water temperatures regularly above 25 ° C. The edge regions are even warmer. In winter it freezes regularly and often has from January to March, a closed ice cover.

The theoretical water renewal time of 0.8 years, the mean discharge 0.56 m³ / s

The lake is holomiktisch and has two circulation periods in spring and autumn.

The lake water has a hardness of approximately 10 degrees of hardness, is thus medium hard. The electrical conductivity is 280 to 330 ĩS / cm. The phosphorus concentration in the surface region is about 8 mg per cubic meter, the lake is so as oligotrophic, so nutrients to classify.

The dominant algae are the dinoflagellates Ceratium Gymnodinium hirundinella and helveticum, and various diatoms of the genus Cyclotella. The animal plankton is made up of 14 species of rotifers and several small crabs together: Eudiaptomus gracilis, Mesocyclops leuckarti, Thermocyclops sp, and the water flea Daphnia hyalina species, Daphnia cucullata, Bosmina longirostris, Diaphanosoma brachyurum, Ceriodaphnia pulchella and Leptodora kindtii. . In oxygen-poor deep water dominates the tufts mosquito larva Chaoborus flavicans.

Around 1975, the zebra mussel ( Dreissena polymorpha ) was introduced into the lake, its larva is part of the plankton.

The main fish species were 1992 white bream and carp other fish, besides also pike and catfish. In 2009, the main fish perch, roach and rudd, the bass provides about half of all individuals. The catfish is still well represented.

In the 20th century, largemouth bass, perch, eel, grass carp, silver carp and whitefish were used sporadically occurs also lake trout used. In recent years, Amur and silver carp could no longer be detected.

In total there are 19 species of fish: whitefish, lake trout, pike, catfish, eel, chub, bream, bitterling, silver bream, crucian carp, carp, arbor, roach, rudd, tench, silver carp, perch, walleye and largemouth bass.

In the shore areas of the lake as well as in -and outflows, there are occurrences of the crayfish.

Use

The lake is privately owned and is a popular bathing waters. The fishing rights are privately owned, the fishing plays a certain role.

On the south bank the campsites are for 3,000 guests.

Lake-dwelling

On the shoal in the lake was around 6000 years ago, a lake-dwelling that was used about 300 years. It is among the oldest of four Pfahlbauperioden in Central Europe. The water level of the lake is estimated to have the time to around 1.5 m lower than today, therefore towered the shoal in part as an island from the water. The piles were made ​​from different types of wood. Two oak logs were dendrochronologically on the felling year 3947 and 3871 BC. Radiometric data from other finds are indicated by 4340-3780 BC. In the settlement, there were two types of houses: log cabins with lehmverschmierten walls and half-timbered houses of wattle. The number of houses is not known. The pottery found in the settlement is allocated to the type Lasinja - Kanzianiberg belonging to the Danubian culture in the Copper Age. Among the animal bones found dominates wild game, especially the red deer with 59%. Cattle are also represented with 13% to any significant extent. There is also evidence that copper processing, but the findings are not safe in the earliest period to classify.

Conservation

With the exception of the North Shore are most parts of the lake as its catchment area in the conservation area Keutschacher Seental.