Köthener See

The Köthener Lake is a shallow water in the catchment area of the Spree and Dahme with a size of 148 ha

Geography

The Köthener lake is part of the territory of the municipality Maerkisch Buchholz in Brandenburg Dahme- Spreewald. It lies on the western edge of the Lower Spree forest at the foot of the mountains Krausnicker. On the south shore the village Köthen, a district of Maerkisch Buchholz is located. Which belongs to Köthen settlement Neuköthen is located north of the lake.

The Köthener lake extends in an east-west direction and has a length of 2.25 km. The greatest width is in the east and is about 1 km. East of the village Köthen is an island in the lake.

General

Originally belonged Köthener lake for water catchment area of ​​the River Spree. Since the construction of Dahme- Umflutkanals water from the river is diverted through the Köthener See the Dahme. The Dahme- Umflutkanal flows, coming from the east of Leibsch, in the north-eastern area of ​​the lake and leaves it after a few hundred meters back to the northwest. More Spree water is supplied to the Köthener See over the edge of the water channel Burger Spree. The lake is Köthener country waterway of class C. Because of a barrage in the Dahme- Umflutkanal in Mark- Buchholz, just before the confluence with the Dahme, the water system, however, is not navigable.

The northern, western and southern shores of the lake consists of Köthener higher Talsanden and is planted with pine and pine mixed forest. The eastern shore is part of the lowland area of the sub- Spreewald and is vermoort. Because of the intensive silting trend in this area of ​​the eastern part of the lake with adjacent peat bogs as a conservation area is designated " sedimentation zone Köthener See ". The reed belts of the lake, except for areas on the north shore, about 30 to 50 m wide. On the east bank the width of the reed belt is, however, up to 200 m and more. The Narrow-leaved Cattail displaces increase the reed.

In Köthen is located directly on the lake shore a youth hostel with a beach and jetty. The Köthener lake is therefore often Destination of juvenile water walkers.

Geology

The Köthener lake is located in a glacial trough, whose origin is already in the channel formation of the Elster glaciation. The glacier ice ages later took advantage of elderly and gutter systems often have characterized them until today partially preserved. The channel, which is now used by the Spree from Leibsch and from Lake Neuendorf, runs from the northeast to the Krausnicker mountains coming, and is divided here into two arms. The running south arm now forms the Talung the Lower Spree Forest. The branch border to the west arm runs along the northern flank of the Krausnicker mountains. In this channel section are Köthener lake and the seven small fens in Köthen. The further course of this channel branch is superficial no longer be seen. 20,000 years ago took advantage of the glaciers of the Brandenburg stage of Weichselkaltzeit this channel. In the area of ​​Heideseen there was then a glacier and the resulting swelling glacier flow spilled the rest of the gutter with Sander sands.

The thickness of the lacustrine sediments at the bottom of the lake Köthener indicates that the glacier sole here at 30 to 35 m above sea level. NN was, and the lake during the early post-glacial period must have had a depth of up to 18 m. Today, the lake bottom consists of a powerful Muddeschicht so that the lowest point is only about 2 m.

Despite its location in a glacial trough, Köthener lake is not a typical Rinnensee. In relation to the Krausnicker mountains, the terminal moraine of the Weichselian glacier and the higher-lying Sander west upstream, you can consider him a Endmoränenstausee.

Hydromorphology

Stratification and circulation

Because of its shallow depth, the Köthener See no stratification of the water masses in different temperature or Konvektionsebenen. A full water circulation, driven by the wind, there is throughout the year. Only occur when ice closed because of the density anomaly of water stagnation phases.

According to the classification of lakes according to the number of full circulation in the year, is the Köthener See, like most shallow lakes of the temperate zone, a polymiktisches waters.

Chemical and trophic characteristics

The lake has Köthener with pH to 8.1 slightly alkaline conditions. After, developed on behalf of the Federal Environment Agency documentation of the Technical University of Cottbus, Department of Freshwater Conservation, the measurements furnished trophierelevanter parameters for the period 1992 to 1994 results, which identify the lake as high polytroph. In the period of calculation of the total phosphorus concentration ranged from 80 to 110 ug / l, in the spring of 1994, even 174 ug / l The phosphorus concentration is correlated with the amount and species composition of the diatom flora. The chlorophyll a concentration was extremely high with values ​​from 65 to 100 ug / l. The mean total nitrogen concentration ranged from 1992 to 1994 unchanged at 1.5 mg / l

For the determination or derivation of potentially natural trophic status of the lake Köthener are no adequate investigation results. This would require extensive drill core analyzes the composition of the diatom flora are carried out in the Muddeschicht of the sea floor.