A Persistent Problem: Toxic Algae Blooms in Stever River, Haltern am See
1. The Current Situation
Warning Issued Regarding Harmful Algae Blooms in Local Lakewater Body
The Stever River near Haltern am See is currently grappling with an outbreak of toxic blue-green algae (cyanobacteria), resulting in a high concentration of harmful algae, including toxic strains. Contact with the water in the affected section is discouraged due to its current condition, with swimming already prohibited.
2. The Impact on the River's Ecosystem
The algal bloom has resulted in a thick carpet of foam and algae on the water's surface. Despite the concerns, Gelsenwasser, the local water supplier, assures that the current fish values are normal, and the fish are doing well. However, the oxygen levels in the water are rapidly decreasing, especially at night, posing potential threats to aquatic life.
3. Measures Taken and Challenges Encountered
Gelsenwasser has been artificially aerating the Stever for years to enrich the water with oxygen. Recently, surface aerators and a long aeration hose at the bottom of the river have been installed to combat the algal bloom. Despite these efforts, they have not been effective against the strong bloom.
4. Public Safety and Awareness
Around 20 warning signs have been temporarily erected along the Stever, advising dog owners not to let their pets into the water. The city of Haltern am See has also taken steps to inform the public, with warning signs being erected on August 14, 2025, at 11:30 AM.
5. The Stever's History of Issues
The Stever has been referred to as a "chronic patient" due to its frequent issues. In recent years, several large fish kills have occurred in the river, raising concerns about its health. The affected section of the Stever is located between the Talsperre Hullern and the Halterner Stausee.
6. Future Considerations
Further measures may be considered if necessary for the Stever, with integrated watershed management focusing on nutrient control and habitat restoration to improve water quality and sustain aquatic life. The city of Haltern am See and Gelsenwasser continue to closely monitor the situation, working towards ensuring the safety and health of the Stever River.
More comprehensive science and environmental-science research could lead to the development of more effective solutions to address the persistent toxic algae blooms in the Stever River, contributing to the health-and-wellness of both aquatic life and the public. The city of Haltern am See and Gelsenwasser are encouraged to collaborate with experts in these fields to implement strategies for sustainable water management and long-term improvement of the Stever's ecosystem.
