The Cottbuser Ostsee (Cottbus Eastern Lake; dsb, Chóśebuski pódzajtšny jazor) is an

artificial lake A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

under development on the grounds of the former

open-pit Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock (geology), rock or minerals from the earth from an open-air pit, sometimes known as a Borrow pit, b ...

lignite Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat ...

mine :de:Tagebau Cottbus Nord near

Cottbus Cottbus (; Lower Sorbian: ''Chóśebuz'' ; Polish: Chociebuż) is a university city and the second-largest city in Brandenburg, Germany. Situated around southeast of Berlin, on the River Spree, Cottbus is also a major railway junction with exten ...

Brandenburg Brandenburg (; nds, Brannenborg; dsb, Bramborska ) is a states of Germany, state in the northeast of Germany bordering the states of Mecklenburg-Vorpommern, Lower Saxony, Saxony-Anhalt, and Saxony, as well as the country of Poland. With an ar ...

, Germany.

Dimensions

When complete, it is to cover a surface area of , making it one of the biggest artificial lakes in the country. At a maximum depth of and an average depth of between and the lake is to have a total water volume of once flooding is complete. Until the lake is complete, the biggest artificial lake in Germany by surface area (likewise created by conversion of a former lignite mine) is

Geiseltalsee Geiseltalsee, literally Geisel valley lake, is at about the largest artificial lake by area in Germany. Once flooding of the Cottbuser Ostsee is complete it will surpass Geiseltalsee in surface area, covering . Geiseltalsee lies in the Saalekreis ...

which covers some . However, the water volume of Geiseltalsee is almost three times larger at . For comparison, Germany's largest lake,

Lake Constance Lake Constance (german: Bodensee, ) refers to three Body of water, bodies of water on the Rhine at the northern foot of the Alps: Upper Lake Constance (''Obersee''), Lower Lake Constance (''Untersee''), and a connecting stretch of the Rhine, ca ...

, covers at a depth of up to and contains some of water. The largest

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

(i.e. an artificial lake created via a dam) in Germany by surface area is

Forggensee The Forggensee, also called the Roßhaupten Reservoir, is a reservoir located north of Füssen in the county of Ostallgäu in Bavaria, Germany and one of many lakes in the region around Hohenschwangau and Neuschwanstein castles. With a surface ...

in Bavaria with a surface area of and a maximum water volume of . However, this lake is reduced to a "rump" of surface area in winter.

History

The lake covers what used to be the open pit lignite mine "Tagebau Cotbus Nord" which produced a total of of coal during its operation from 1981 to 2015. The last coal was mined in December 2015 and subsequently work began on converting the mine into a lake. Flooding started in 2019 but had to be interrupted several times due to low water levels in the nearby

Spree River Spree may refer to: Geography * Spree (river), river in Germany Film and television * ''The Spree'', a 1998 American television film directed by Tommy Lee Wallace * Spree (film), ''Spree'' (film), a 2020 American film starring Joe Keery * Spree ( ...

. The lake is to become part of the

Lusatian Lake District The Lusatian Lake District (german: Lausitzer Seenland, dsb, Łužyska jazorina, hsb, Łužiska jězorina) is a chain of artificial lakes under construction in Germany across the north-eastern part of Saxony and the southern part of Brandenburg ...

, a chain of artificial lakes mostly the result of open-pit lignite mining.

Name

The name - besides referring to the location of the lake to the East of central Cottbus - can be interpreted as a pun on the German name for the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and from ...

, which is called "Ostsee" in German, the two words only being distinguished by their

grammatical gender In linguistics, grammatical gender system is a specific form of noun class system, where nouns are assigned with gender categories that are often not related to their real-world qualities. In languages with grammatical gender, most or all nouns ...

: "See" meaning "sea" in German is grammatically female, whereas "See" meaning "lake" in German is grammatically male.

References

Buildings and structures in Spree-Neiße Artificial lakes of Germany {{Lake-stub