[1] Once flooding of the Cottbuser Ostsee is complete it will surpass Geiseltalsee in surface area, covering 19 square kilometres (7.3 sq mi).

After World War II, the area came under the control of the Soviet Occupation Zone which would soon give rise to the German Democratic Republic (GDR).

Due to a desire for autarky and a dearth of natural resources other than lignite (and uranium in the Ore Mountains, which however mostly went to the Soviet nuclear program), lignite mining ramped up sharply in the GDR, converting a country of less than 20 million inhabitants to the world's top producer and user of this commodity.

After German reunification, the demand for lignite dropped sharply as reunified Germany could import petroleum on the world market and superior domestic hard coal from the Ruhr area and other then-active mining areas in West Germany competed with lignite.

Besides allowing quick conversion to new uses, quick flooding is also desirable as it reduces the risk and amount of acid mine drainage (minerals like pyrite which are stable in anoxic conditions oxidize if exposed to air, giving rise to sulfuric acid - this process is slowed or stopped by covering those minerals in water).