Geomorphic change along the Rönne river : Effects caused by dams

Abstract: Many rivers can shape their path through the landscape with erosion and deposition where the riverbed and riverbanks both shape the direction and energy of the flow. The river flow can erode the riverbanks and create meanders which is when the river creates bends in its path that become increasingly curved. Meanders are affected by natural aspects of the landscape but also by anthropogenic structures like dams. The Rönne river is the largest river in the region of Skåne in southern Sweden and along it is three major dams that act as barriers for fish species. These dams are scheduled to be removed in 2024. To estimate how the Rönne river may react to the removal of these dams, the river’s erosion, deposition, and stream width was studied for the years 1926-1934, 1960, 1970 and 2018. By understanding how the dams have affected the river, it may be possible to argue how the river will change after the dams are removed. Erosion was greatest downstream of the dams but changes to deposition and stream width did not follow the pattern indicative with dams. The dams were not the determining factor and other factors such as land use and surficial geology are more impactful to the morphological changes in the river. Issues with the method and used materials affected and created uncertainty with the results. Improvements and changes are therefore needed for the method and the materials to better determine how the Rönne river is affected by the studied dams.