Author(s): Helene Ella Ekrem; Jan Hrebrina; Elena Pummer
Linked Author(s): Elena Pummer
Keywords: No Keywords
Abstract: Extensive flood events in rivers have led to mobilization of large boulders that previously have remained stable over longer periods of time, and that under normal flow conditions are considered “immobile”. The increased frequency in large-scale flood events expected in the future, emphasizes the importance of predicting boulder displacement. Most research on sediment transport focuses on smaller particles, typically represented by a characteristic diameter, leaving the behavior of larger boulders under high-flow conditions less understood. An ongoing PhD project at NTNU investigates the incipient motion of boulders under varying flow conditions, providing a foundation for this study. Building on this work, the present study addresses a research gap by examining how boulder shape and edge-smoothness influence boulder mobilization, which is essential for improving predictions of large-particle transport and associated hazards in rivers. Understanding when and how boulders begin to move is important for hydropower operations, as mobilized boulders can pose risks to infrastructure, alter flow patters if settling near intakes or outlets, obstruct water conveyance, and ultimately reduce power production efficiency.
Year: 2026