The Dümmer () or officially Dümmer See is a large

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

in southern

Lower Saxony Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state (') in northwestern Germany. It is the second-largest state by land area, with , and fourth-largest in population (8 million in 2021) among the 16 ...

(

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

). It has a surface of 13.5 km² and an average depth of one metre. Its elevation is 37 metres. Dümmer is a popular resort for water sports, but also an important

biotope A biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. ''Biotope'' is almost synonymous with the term "habitat", which is more commonly used in English-speaking countrie ...

for water birds and located in a zone especially frequented by migratory birds. A large section of its shore is protected by nature reserve areas.

Location

The Dümmer is located in the Dümmer depression. One and a half miles to the west, the Damme Hills begin to rise, eventually reaching a height of 145 m. Around the lake are

fen A fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires. T ...

s (''Niedermoore'') and

raised bog Raised bogs, also called ombrotrophic bogs, are acidic, wet habitats that are poor in mineral salts and are home to flora and fauna that can cope with such extreme conditions. Raised bogs, unlike fens, are exclusively fed by precipitation ( ombro ...

s (''Hochmoore''). The lake lies in the Dümmer Nature Park, which is just under 500 km² in area, and in which the Damme Hills and

Stemweder Berg The Stemweder Berg (also known as the Stemmer Berge)Because it has several rounded summits, it should really be called the ''Stemweder Berge'' i.e. "Stemwede Hills". is a ridge above sea levelHeight according tDeutsche Grundkarte auf geoserver.nr ...

form the central elements of the landscape. The open water of the lake belongs entirely to the district of

Diepholz Diepholz (; Northern Low Saxon: ''Deefholt'') is a town and capital of the district of Diepholz in Lower Saxony, Germany. It is situated on the rivers Hunte and Lohne, approximately 45 km northeast of Osnabrück, and 60 km southwest of ...

, but on its western shore the district of Vechta extends up to the dyke foreland. Near Dümmerlohausen the district boundary comes within a few metres of the shoreline. To the southwest by the mouth of the River Hunte a tip of the territory of the district of Osnabrück advances to within half a kilometre of the lake. Whilst Diepholz district belonged to the

Electorate of Hanover The Electorate of Hanover (german: Kurfürstentum Hannover or simply ''Kurhannover'') was an electorate of the Holy Roman Empire, located in northwestern Germany and taking its name from the capital city of Hanover. It was formally known as ...

from 1585 (

County of Diepholz The County of Diepholz (West Low German: ''Deefholt''), that was first known as the Lordship of Diepholz, was a territory in the Holy Roman Empire in the Lower-Rhenish-Westphalian Circle. It was ruled by the Noble Lords, later Counts, of Diepholz ...

) and 1582 (

County of Hoya The County of Hoya (German: ''Grafschaft Hoya'') was a state of the Holy Roman Empire, located in the present German state of Lower Saxony. It was centered on the town of Hoya on the middle Weser river, between Bremen and Nienburg; the area now ...

), the territory of the district of Vechta belonged for centuries to the Diocese of Münster and only became part of Oldenburg in 1803 after the

German Mediatisation German mediatisation (; german: deutsche Mediatisierung) was the major territorial restructuring that took place between 1802 and 1814 in Germany and the surrounding region by means of the mass mediatisation and secularisation of a large number ...

. Hence it counts as part of

Oldenburg Münsterland The Oldenburg Münsterland, otherwise called Oldenburger Münsterland or Oldenburgisches Münsterland, is a region in Lower Saxony, Germany and the administrative area that comprises the federal districts of Cloppenburg and Vechta. Unofficially, ...

Character

The Dümmer is, after the

Steinhuder Meer Lake Steinhude, german: Steinhuder Meer, , is a lake in Lower Saxony, Germany located northwest of Hanover. Named after the nearby village of Steinhude, it has an area of about , making it the largest lake of northwestern Germany. At the same t ...

, the second largest lake in Lower Saxony. With its water surface of 13.5 km ² - the area within the ring dyke including siltation zones is 16 km ² - and maximum water depth of just 1.50 m, it is good for swimming and water sports. The shallow lake with its flat beaches on the western and eastern shore is up to 5 km long from north to south and up to 3.4 km wide from west to east. The lake is crossed by the River Hunte, which leaves the lake via several branches, the largest of which is not called the "Hunte" but the Lohne. Other branches are the

Grawiede Grawiede is a river of Lower Saxony, Germany. It is one of the outflows of the lake Dümmer, and it flows into the Hunte near Diepholz. See also *List of rivers of Lower Saxony All rivers in the German state of Lower Saxony flow directly or in ...

and the artificial Wätering, the Dorflohne, Schoddenlohne and Ompteda Canal. Only 13 km north of the lake and 3 km north of

all the branches of the Hunte are reunited. The fish-filled lake, which is also a breeding and resting place for birds, has a variety of

flora Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''. E ...

and

fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoo ...

, which is why the western and the southern shore of the lake are largely protected.Niedersächsischer Landesbetrieb für Wasserwirtschaft, Küsten- und Naturschutz (NLWKN): ''Naturschutzgebiet "Dümmer"''
/ref> Although the lake is only about a metre deep on average, very rich water sources and the Hunte itself ensure that its water level is relatively constant. Previously these headstreams combined with regular heavy rainfall to cause flooding, so that in the 1940s work began to build dykes around the lake. In the period 1941-1945 foreign

forced labour Forced labour, or unfree labour, is any work relation, especially in modern or early modern history, in which people are employed against their will with the threat of destitution, detention, violence including death, or other forms of ex ...

was used for this on a large scale. The reclamation and subsequent lack of annual flooding resulted in algae growing in large quantities in the lake and hence depriving most other organisms of oxygen. The low water level was caused by heavy silting, also a result of dyking the lake. With the help of several locks it was possible to control the high water levels artificially without greatly interfering with nature. Nevertheless, the Dümmer suffers from heavy nutrient pollution caused by intensive agriculture. The remains of New Stone Age settlements have been found on the shores of the Dümmer.

References

Sources

* Friedrich, Ernst Andreas (1980). ''Naturdenkmale Niedersachsens''. Hanover. * Helbig, Andreas J., Ludwig, Jürgen and Belting, Heinrich (1990). ''Die Vögel des Dümmer-Gebietes. Avifauna eines norddeutschen Flachsees und seiner Umgebung'' (Naturschutz und Landschaftspflege in Niedersachsen 21). Hanover * Klohn, Werner (1992). ''Probleme der Raumgestaltung in der Dümmerniederung'' Vechta * Klohn, Werner (1986). ''Verbreitung, Struktur und Funktion der Kleinstwälder und Gehölze in der Dümmerniederung und ihren Randgebieten'' Vechta * Klugmann, Ulrike and Villwock, Ingeborg (1984). ''Dümmer und Wiehengebirge'' (Naturmagazin "Draußen", Heft 35). Hamburg * Sanden-Guja, Walter (1960). ''Der große Binsensee.'' 2nd expanded edition, Stuttgart * Schmidt, Arno (1955). ''Seelandschaft mit Pocahontas.'' Erzählung. * Seehafer, Klaus (1980). ''Der Dümmer See in Farbe. Ein Reiseführer für Naturfreunde''. Stuttgart

External links

* * {{DEFAULTSORT:Dummer Lakes of Lower Saxony LDummer Vechta (district) Ramsar sites in Germany