Germany's largest artificial lake near Cottbus is full

Cottbus. Nine years after its closure, the Cottbus-Nord opencast lignite mine has been flooded. The as Cottbus Baltic Sea known waters have reached a level of 62.5 meters above normal for the first time, according to Lausitzer Energie Bergbau AG (Leag). This means that no more Spree water is flowing into the lake for the time being.

The Cottbus Baltic Sea is 19 square kilometers in size and replaces the Geiseltalsee in the south of Saxony-Anhalt, also a flooded opencast lignite mine, as the largest artificial lake in Germany. Flooding began in April 2019, mostly during the winter months. However, there were repeated interruptions due to dry conditions.

However, it will be years before the lake can be used for tourism. Access to the area is still prohibited. However, one attraction has already been completed: the redesign of the 34-metre-high Merzdorf observation tower. As a local landmark, it attracts thousands of visitors every year. Cottbus also wants to approve an urban quarter on the waterfront. The Mayor of Cottbus, Tobias Schick, said that the region now has "another important asset that will allow us to proceed with confidence with the planning and further development of this truly great gem".

Leag uses the water 'for a Floating Solplantto cover the electricity needs of 8,250 households. In addition, the Baltic Sea water is to be heated using the currently largest seawater heat pump in Germany. Supply district heatingto replace the existing heat supply from the Jänschwalde coal-fired power plant. According to the Left Party, the costs for this project alone are estimated at 80 million euros.

However, it is not yet clear whether the lake can be used as a water reservoir. Especially in dry periods, the metropolis of Berlin lacks the water of the Spree and, in Brandenburg, the unique landscape of the Spreewald. "The main argument for the expansion of the reservoir and for the water transfers is to cover the water requirements of the Berlin-Brandenburg metropolitan region and the Unesco Spreewald Biosphere Reserve," according to a statement published in June 2023. Federal Environment Agency study on the water management consequences of the lignite phase-out in Lusatia. Accordingly, the Cottbus Baltic offers a storage capacity of 27 million cubic meters.

According to Leag, around 170 million cubic meters of Spree water have flowed into the Baltic Sea so far. However, there are still some cavities in the ground, similar to a sponge. As these affect stability, they must also be completely filled. Another 50 million cubic meters of water are needed for this, it was said. For the time being, the Czech-owned energy company is continuing to work on an outlet structure. In addition, some sections of the banks are still slipping and need to be secured.

Cottbuser Ostsee is one of more than 500 lakes that have been created by opencast lignite mining in Germany, according to the Federal Environment Agency.

SZ