The Cottbuser Ostsee, Germany’s largest artificial lake created from a former coal mine, is once again making headlines. While the project was envisioned as a beacon of transformation for Lausitz’s post-coal future, recent developments highlight the challenges in balancing environmental concerns, water management, and future tourism potential.
Water Levels Drop After Reaching Milestone
After years of painstaking flooding efforts, the Cottbuser Ostsee finally reached its targeted fill level in late 2024. However, within months, the water level dropped by around 30 centimeters, largely due to high evaporation rates. Environmental groups warn that such fluctuations could worsen the existing water scarcity in the region, which already relies heavily on the Spree River.
René Schuster from the environmental group Cottbus emphasized: “The Cottbuser Ostsee is a prime example of how artificial lakes act as vast evaporation surfaces. This puts further strain on the Spree, reducing available water for nature and communities.”
Largest Artificial Lake in Germany
Spanning an area of about 1,900 hectares, the Cottbuser Ostsee is the largest lake ever formed from a former opencast coal mine in Germany. Yet, this massive project is only one part of a broader plan. Energy company LEAG, which is responsible for both coal mining and the subsequent renaturation, intends to create up to 8,000 hectares of artificial lakes across Lausitz.
Environmentalists argue that this approach is unsustainable. With the end of coal mining, groundwater regeneration will take decades, possibly until 2100, leaving a gap in regional water supply. Filling and maintaining these lakes, critics say, only adds more pressure to the system.
LEAG Defends the Project
Despite the criticism, LEAG insists that the Cottbuser Ostsee does not contribute significantly to regional water shortages. According to company spokesperson Kathi Gerstner, water from the Spree is only redirected to the lake when the river has surplus levels. Additionally, the Ostsee can serve as a temporary reservoir during heavy rainfall, storing excess water and releasing it back into the Spree during dry spells.
LEAG maintains that the long-term vision remains clear: the lake should evolve into a hub for tourism, recreation, and nature. Plans include boating, fishing, and potentially swimming once safety measures are fully in place.
Tourism Prospects Still Uncertain
While the Cottbuser Ostsee holds promise as a tourist attraction, safety concerns remain. In 2023, unexpected landslides along the banks raised doubts about the stability of the lake’s shores. Experts now estimate that ensuring full safety could take until at least 2030, delaying opportunities for bathing and other leisure activities.
Still, local stakeholders hope that the lake will one day become a major draw for the Lausitz region, boosting its post-coal economy. The combination of natural beauty and industrial history gives the Cottbuser Ostsee a unique identity, one that could help redefine the area’s future.
Future of Lausitz’s Water Landscape
The Cottbuser Ostsee is the first artificial lake in Lausitz directly managed by LEAG. More projects are underway, including lakes in Jänschwalde, Welzow-Süd, Nochten, and Reichwalde. However, critics caution that repeating the Ostsee model could deepen the region’s water crisis.
Instead of prioritizing wide, shallow lakes prone to evaporation, environmental groups urge the restoration of more land surfaces and the creation of deeper, smaller lakes. This approach, they argue, would be more sustainable and less taxing on the Spree’s fragile water system.
As Lausitz transitions away from coal, the fate of the Cottbuser Ostsee will serve as a test case. Will it emerge as a successful example of transformation, blending ecology, recreation, and heritage? Or will it stand as a costly reminder of the difficulties in reshaping post-industrial landscapes?
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