Cottbuser Ostsee
The Cottbuser Ostsee is an artificial lake under development on the grounds of the former open-pit lignite mine :de:Tagebau Cottbus Nord near Cottbus, Brandenburg, 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 is Geiseltalsee which covers some. However, the water volume of Geiseltalsee is almost three times larger at. For comparison, Germany's largest lake, Lake Constance, covers at a depth of up to and contains some of water. The largest reservoir in Germany by surface area is Forggensee 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. The lake is to become part of the Lusatian Lake District, a chain of artificial lakes mostly the result of open-pit lignite mining.