Alluvial fan morphodynamics: Advances and future prospects

Abstract

Alluvial fans, fan-shaped depositional landforms located at the outlets of mountain rivers and gullies, provide valuable insights into regional environmental change, geomorphic evolution, and hazard processes related to floods and debris flows. While research on fan morphometry, sedimentology, and paleoenvironment reconstruction is extensive, fan morphodynamics, especially the quasi-cyclic processes of deposition, erosion, and flow path avulsion, remain understudied. This review assesses the current state of research on fan morphodynamics and outlines future directions. It highlights key findings, including the primary and secondary processes that drive fan development, the mechanisms of flow path avulsion, and the associated sediment dynamics and geomorphic effects. Crucially, it underscores the need for real-time field monitoring to complement existing field investigations and modeling efforts. Enhancing real-time observations will significantly advance the understanding of fan morphodynamics, sediment dynamics, and geomorphic processes, ultimately improving hazard mitigation strategies.