ABSTRACT
The River Iller, a tributary of the Danube River, can be classified as heavily modified. As result of severe human activities, ongoing river bed erosion occurred in the past. Within the conducted study a coupled 1D-2D model is used to investigate a) the morphological bed changes on a long term as well as b) the effects of river training structures in the lower reach of the River Iller. In total six scenarios with a different number of revetments in combination with either 20 m or 40 m river bed widening are investigated. The results of the simulations show that without an implementation of river training structures the ongoing river bed degradation will continue. From the scenario simulations can be seen that the implementation of revetments in combination with the river bed widening have a positive effect on the future bed evolution. However, the results of the simulations show that the implementation of four revetments can stabilize the river bed in a way that equilibrium conditions can be reached along the whole investigated river section. An additional performed study regarding the habitat quality shows that the planned measures result in an increase of areas with a good habitat quality for the considered fish species of the grayling.
