Koethener lake
| Koethener lake | ||
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| Bathing beach in Koethen | ||
| Geographical location | District of Dahme-Spreewald , Brandenburg ( Germany ) | |
| Tributaries | Rand Canal (Wasserburger Spree), Dahme-Umflutkanal | |
| Drain | Dahme flood canal | |
| Places on the shore | Köthen (part of the municipality of Märkisch-Buchholz) | |
| Data | ||
| Coordinates | 52 ° 4 '50 " N , 13 ° 48' 43" E | |
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| Altitude above sea level | 43 m above sea level NN | |
| surface | 1.48 km² | |
| length | 2.25 km | |
| width | 1 km | |
| Maximum depth | 2 m | |
The Köthener See is a shallow body of water in the catchment area of the Spree and Dahme with a size of 148 ha.
geography
The Köthener See belongs to the territory of the municipality of Märkisch Buchholz in the Brandenburg district of Dahme-Spreewald . It is located on the western edge of the Unterspreewald at the foot of the Krausnicker Mountains . The village of Köthen , part of Märkisch Buchholz, is on the south bank . The Neuköthen residential area belonging to Köthen is located north of the lake.
The Köthener See stretches 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. There is an island in the lake east of the village of Koethen.
General
Originally, the Köthener See belonged to the water catchment area of the Spree. Since the construction of the Dahme flood canal , water from the Spree has been diverted to the Dahme via Lake Köthen. Coming from Leibsch from the east, the Dahme Umflutkanal flows into the northeasternmost area of the lake and leaves it again after a few hundred meters in the northwest. More water from the Spree is supplied to Lake Köthen via the edge canal from the Wasserburger Spree. The Köthener See is a state waterway of class C. Due to a barrage in the Dahme flood canal in Märkisch-Buchholz, shortly before the confluence with the Dahme, the water system is not continuously navigable.
The northern, western and southern shores of Lake Köthen consist of higher valley sand and are planted with pine and mixed pine forests. The eastern bank belongs to the lowland area of the Unterspreewald and is moored. Because of the intense silting tendency in this area, the eastern part of the lake with the bordering moorland is designated as a nature reserve "Silting Zone Köthener See". The reed belt of the lake is, apart from areas on the north bank, approx. 30 to 50 m wide. However, the width of the reed belt on the east bank is up to 200 m and more. The narrow-leaved cattail is increasingly displacing the reeds .
In Köthen there is a youth hostel with a beach and jetty right on the shore of the lake . The Köthener See is therefore often a travel destination for young water hikers.
geology
The Köthener See lies in a glacial channel , the origin of which can be found in the channel formation during the Elster Ice Age . The glaciers of later Ice Ages often used older channel systems and have thus partially preserved their course to this day. The channel, which is used today by the Spree from Leibsch and from Neuendorfer See , runs from the northeast towards the Krausnicker Mountains, and divides here into two arms. The arm running to the south today forms the valley of the Unterspreewald. The arm branching to the west runs on the northern flank of the Krausnicker Mountains. The Köthener See and the seven small heathland lakes near Köthen are located in this section of the channel . The further course of this channel branch can no longer be seen on the surface. The glacier of the Brandenburg stage of the Vistula Cold Age used this channel 20,000 years ago . At that time there was a glacier gate in the area of the Heideseen and the glacier stream that gushed from it covered the further course of the channel with sand .
The thickness of the limnic sediments at the bottom of the Köthener See shows that the glacier bottom is here at 30 to 35 m above sea level. NN was, and the lake during the early post-glacial must have a depth of up to 18 m had. Today the lake bed consists of a mighty mud layer , so that the deepest point is only about 2 m.
Despite its location in a glacial channel, the Köthener See is not a typical channel lake . In relation to the Krausnicker Mountains, the terminal moraine of the Weichselian glacier and the higher lying sander to the west, it can be seen as a terminal moraine reservoir.
Hydromorphology
Stratification and circulation
Because of its shallow depth, the Köthener See does not show any stratification of the water masses in different temperature or convection levels . Full water circulation , driven by the wind, exists all year round. Stagnation phases only occur when the ice cover is closed because of the density anomaly of the water .
According to the classification of lakes according to the number of full circulations per year, the Köthener See, like most shallow lakes in the temperate zone , is a polymictic body of water.
Chemical and trophic characteristics
The Köthener See has a weakly alkaline pH value of 8.1. According to a documentation of the Technical University Cottbus , Chair of Water Protection , prepared on behalf of the Federal Environment Agency , the measurements of trophy-relevant parameters in the period from 1992 to 1994 produced results that identify the lake as highly polytrophic . During the assessment period the total phosphorus concentration was between 80 and 110 µg / l , in spring 1994 even 174 µg / l. The phosphorus concentration correlates with the amount and the species composition of the diatom flora . The chlorophyll a concentration was extremely high with values of 65 to 100 µg / l. The mean total nitrogen concentration was unchanged from 1992 to 1994 at 1.5 mg / l .
There are insufficient test results for the determination or derivation of the potentially natural trophy of the Köthener See. For this purpose, extensive drill core analyzes would have to be carried out on the composition of the diatom flora in the mud layer of the lake bed.
See also
Web links
- Map of the Spreewald Biosphere Reserve on the Biosphere Reserve website
- Boundary description of the NSG "Silting Zone Köthener See" in the ordinance on the establishment of nature reserves; see protection zone II, no.17.
- Olaf Juschus: The young moraine south of Berlin - Investigations into the young Quaternary landscape development between Unterspreewald and Nuthe. Dissertation Humboldt University Berlin 2001, doi : 10.18452 / 14585 .
- Documentation of the condition and development of the most important lakes in Germany. Part 5: Brandenburg. Final report, R&D project FKZ 299 24 274, environmental research plan of the BM for the environment, reactor safety and nature conservation (PDF file, 2 MB).
- Paleolimnian model construction and biocene-based assessment approaches for river lakes using the example of diatoms (= specialist articles by the State Environment Agency . Issue No. 93, 2005. PDF file, 2 MB).