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04/12/2022 | Pressemitteilung

University teaching: How practical water protection is successful

How quickly a body of water develops positively when nature is allowed to take its course again can be seen on the Diemel: Within a short time, a renaturalized section of the river has recovered significantly. Now a section of the Eder river in northern Hesse is also earmarked for renaturation as part of a university teaching-learning project.

Successful renaturation: Newly detected fish in the Diemel (Photo: Eligehausen)

Brown trout, brook lamprey, bullhead, minnow - these four fish species are now also once again cavorting in the Diemel near Marsberg in the Sauerland region. These species immediately accepted the newly created habitats, a clear sign of the success of the measure. This is measurable through control fishing: Whereas in May 2021 just two species and less than ten fish in total were counted in the renaturalized section of the river, in September 2021 there were already three species and 102 fish. At the beginning of 2022, the minnow was detected as the fourth fish species. This typical species of low mountain range rivers was previously absent in large sections of the Diemel. "This is particularly pleasing, especially also the first-time detection of juveniles of the brook lamprey and the high proportion of bullheads," says Jens Eligehausen. He is a lecturer at the Department of Civil and Environmental Engineering at the University of Kassel. The newly detected fish species make very high demands on water quality and water body structure. "The fact that they have now found a habitat again in the Diemel speaks for the success of the measure," Eligehausen continues.

As part of a practical seminar at the University of Kassel, Eligehausen has been working with students of landscape planning and environmental engineering since 2020 to restore part of the river section of the upper Diemel to its original state. In addition to the Department of Landscape and Vegetation Ecology at the University of Kassel, the planning network for sustainable regional development (Planar e.V.) and the Diemel Water Association in Marsberg are cooperation partners.

The overall objective of the project seminar is to sustainably increase the resilience of flowing waters in the context of the climate crisis, thereby counteracting the loss of biodiversity and strengthening the local recreational function of water bodies. This takes the form of hands-on teaching on real-life problem cases identified with the help of geographic information systems (GIS). In the renaturation measure, the students removed bank reinforcements and created or expanded side channels and shallow water zones with calmed currents as reproduction sites and nursery habitats for young fish, amphibians and other species.

The success of the project was demonstrated by a student in an accompanying scientific paper. She proved that the -naturalness according to the official seven-stage evaluation system improved by two or three classes depending on the section from "class 5 - strongly changed" to "class 2 - slightly changed" or "class 3 - moderately changed".

"Our Diemel project has impressively shown how practical water protection can be carried out and how university teaching makes a decisive contribution to this," says Eligehausen. It is therefore not surprising that it will be transferred to the Eder in northern Hesse in the summer semester of 2022 as part of a course on GIS-based watercourse development planning: "This is another practical and very promising contribution to watercourse development on a watercourse system that is particularly important in terms of nature conservation," emphasizes Eligehausen. In addition, Eligehausen would like to carry out further renaturation projects together with cooperation partners as part of his teaching at the University of Kassel and apply for state funding for this purpose.

Further info:

Jens Eligehausen