High-latitude fluvial dynamics under hydroclimatic shift – Insights on sediment transport and river morphology

Rivers serve as primary conveyors of sediment, continuously reshaping landscapes through fluvial dynamics where hydroclimatic conditions play crucial role in governing the seasonality and magnitude of sediment transport, sediment connectivity and morphological adjustment. In high-latitude regions snowmelt-driven spring floods have traditionally been the major contributor to sediment fluxes. However, climate change is altering the hydroclimatic conditions, leading to hydroclimatic regime shifts with significant implications for sediment transport dynamics, river morphology, and landscape stability. This study assess the impacts of hydroclimatic shifts on sediment transport dynamics in high-latitude rivers, with a focus on seasonality and variability of sediment transport events, and functional sediment connectivity. Using a combination of (1) hydrological, meteorological, and geomorphological time-series data from in situ field measurements, remote sensing, gauging stations, and historical aerial imagery, (2) computational morphodynamic modelling with high spatiotemporal resolution, and (3) Index of Connectivity and sediment budgeting approaches, this research provides new insights into how climate-driven hydrological changes reshape fluvial sediment transport processes. The study focuses on two meandering rivers in boreal and subarctic environments, both expected to experience contrasting hydrological changes due to climate change. The findings provide critical insights into the seasonality, variability, and long-term trends of sediment transport dynamics and morphological responses in river systems transitioning from Nival control to Pluvial control. In addition, the results emphasize the need for continuous monitoring and advanced modelling, such as digital twins, to capture evolving patterns and thresholds of sediment transport. Future research should integrate real-time data with predictive multimethod approaches to improve understanding of short- and long-term morphodynamic feedback.