Author(s): Christy Ushanth Navaratnam; Aslaug Marie Tvinnereim Otnes And Knut Alfredsen
Linked Author(s): Knut Alfredsen, Christy Ushanth Navaratnam
Keywords: LiDAR sediment transport riverbed morphology flood management salmon habitat
Abstract: The Laerdal River in Norway, a vital habitat for Atlantic salmon and sea trout, has experienced significant morphological changes due to sediment transport, often exacerbated by flooding events. This study compares bathymetric LiDAR data collected in 2018 and 2021 to assess changes in the riverbed over a 10 km stretch. By applying the Digital Elevation Model of Difference (DoD), we quantified sediment deposition and erosion. The preliminary results show substantial sediment deposition, especially influenced by increased sediment supply from the Kuvelda tributary. However, human-induced dredging activities were also observed to alter the riverbed significantly. An average deposition of 0.1 m was identified, with outliers from dredging possibly skewing the value. These findings underscore the importance of sediment dynamics in shaping river morphology and the impact on salmon habitats. The study contributes valuable data for sediment transport models and supports ongoing research to refine flood management strategies and conservation efforts in the face of climate change.
Year: 2025