Geomorfologiska förändringar till följd av vattendragsrestaurering i Vargån, Öreälven, Sverige.

River channelization in Sweden has simplified streams by removing woody debris, rocky outcrops and boulders. Rivers can be restored by reintroducing natural processes but assessing restoration success remains challenging. This study aimed to assess the effectiveness of a restoration in Vargån, Öre River catchment, Sweden, by investigating changes in geomorphic unit (GU) diversity over time and how they associate with in-channel structural elements, banks, thalweg and instream dead wood clusters. GU types were mapped using ArcGIS Pro, based on orthophotos generated in Agisoft Metashape from uncrewed-aerial-vehicle imagery and a geomorphic unit system. Shannon Diversity Index was used to calculate GU diversity, and the intersect tool in ArcGIS Pro was utilized to understand the connection to the four parameters. The result showed a general increase in diversity and evenness and a decrease in dominance. The structural elements fine sediment bars and gravel bars appeared more frequently after restoration, contributing to physical habitats. The number of GU types connected to bank and thalweg increased, indicating lateral diversity. The GUs with biggest percentage change associated with bank were deep and shallow pool, highlighting low-energy GUs association, while high-energy GUs riffle and glide changed most for the thalweg. IDW clusters were often fixed on banks, connected with glides upstream and pools downstream due to flow obstruction and scour. The findings suggest that the restoration has created a more diverse and dynamic river system. Although focused on one reach, the results emphasize the importance of natural river recovery and long-term monitoring to improve restoration methods.