Author(s): Frida M. Niemi; Anders G. Andersson; J. Gunnar I. Hellstrom

Linked Author(s): Anders Andersson, Gunnar Hellström

Keywords: Hydraulic model Delft3D FM Sediment Substrate Spawning habitat European Grayling

Abstract: Hydropower is an important renewable energy source providing flexible operating conditions that balances the increasing intermittent energy from wind- and solar power. However, hydropower facilities significantly alter the rivers ecosystem and impacts its natural flow. Understanding and mitigating hydropeaking effects on fish habitat in regulated rivers could improve the spawning grounds downstream the hydropower facility. One approach is to identify areas suitable as spawning grounds considering depths, velocities and substrate to evaluate the restoration potential. This work aims to find the possible substrate composition in the river by using the bed shear stress data from a Delft3D FM hydraulic model at various flow conditions. This method helps identify suitable locations for adding substrate as a restoration measure ensuring that the material will remain stable and not be washed away by high flows. The distribution of possible substrate sizes was presented at various flow conditions together with a geographical map over the substrate areas. In some areas with potential grayling habitat the shear stress was too high for the preferable substrate meaning that a restoration measure by adding suitable substrate would probably transport the substrate further down in the river. Adding sediment transport or coupling the hydraulic model with individual based models for fish behavior would give a better understanding of the erosion of additional sediment and how it effects the habitat.

DOI:

Year: 2025