„Christened "Kaiman": The Ruhrverband presented its new mowing boat. Pictured (from left): Antje Nielinger-Teuber, Simone Raskob, Markus Rüdel, Hans-Walter Fink, Mayor Thomas Kufen, Boris Orlowski, Matthäus Schallenberg, and Prof. Christoph Donner. Photo: Ruhrverband
„Kaiman“ is supposed to contain Elodea in the Baldeneysee
Essen, Baldeneysee, July 16, 2025. On Wednesday, the Ruhrverband presented a new weeding vessel in the Scheppen harbor: "Kaiman" will be used to specifically combat the aquatic plant Elodea in the Baldeneysee. Together with another vessel already in operation (Baldeneysee.Ruhr reported), the new vessel will enhance maintenance efforts on the lake. Among those attending the christening were Mayor Thomas Kufen, Ruhrverband Chief Professor Christoph Donner, Weisse Flotte Baldeney GmbH Managing Director Boris Orlowski, and IG-Baldeney Chairman Hans-Walter Fink.
aliens in our ecosystems
Originally from North America, the Elodea plant has spread throughout the Ruhr region and increasingly poses a challenge for water sports and recreational use. The good water quality, the result of decades of improvements in wastewater treatment, significantly promotes the plant's lush growth. "The name 'caiman' was chosen deliberately," explains Professor Donner. "It is intended to highlight the ecological changes caused by invasive species. Caimans themselves are aliens in our ecosystems – just like the Elodea."„
Coordinated measures for clean waters
The city of Essen, Ruhrverband, IG Baldeney and the Weisse Flotte Baldeney The companies involved are working closely together. The Ruhrverband provides the mowing boats, the Weissee Flotte Baldeney GmbH is responsible for their personnel and deployment, while the IG Baldeney determines the areas to be mowed in coordination with other companies. Additionally, a loading barge from the Düsseldorf district government is being used to collect the vegetation directly on the water, increasing the efficiency of the work. "Regular mowing is crucial for sporting events and training," emphasizes Mayor Kufen. "For many Essen residents, the Baldeneysee is not only a place of recreation but also a sporting home." Without mowing, the operation of the passenger ships of Weisse Flotte Baldeney GmbH would be severely restricted or even impossible.
Growth with risks – Elodea remains a challenge
While the aquatic plant provides habitat for numerous aquatic creatures, its massive biomass poses problems for users. The research project "Elodea II" showed that alternatives such as mechanical soil cultivation or competing plantings proved largely ineffective. Mowing is currently the only practical measure. Test runs in June and July of this year yielded meager results. Nevertheless, experts warn that with the current weather conditions—plenty of sunshine, high temperatures, and clear water—plant growth could increase dramatically at any time. Elodea can grow up to 20 centimeters per day.
Looking back at 2024: Record year for plant growth
In the summer of 2024, over 510 tons of Elodea were harvested from the Baldeneysee The amount of vegetation removed was a significant amount – a figure surpassed only by the heatwave of summer 2018. More than 50 container loads were needed to transport the cut vegetation. Current preparations aim to ensure that the lake remains usable even with increasing vegetation, and Kaiman is expected to provide effective assistance.
