Qualitative assessment model for longitudinal riverbed erosion and deposition based on suspended sediment impacts and hydraulic geometry relationship

Abstract

Despite extensive research, simply predicting changes in the riverbed morphology, particularly determining whether erosion or deposition will occur, remains a significant challenge. This study introduces an analytical model that integrates hydraulic geometry with sediment transport equations to qualitatively predict the evolution of riverbed morphology in the longitudinal direction. Building on the foundational theories of Leopold and Maddock (1953), this model extends traditional hydraulic geometry by incorporating downstream exponents of suspended sediment concentration, revealing four distinct riverbed evolution patterns. This provides a comprehensive and practical understanding of sediment dynamics in rivers. The model was validated against field data and computational simulations to ensure its reliability in capturing complex fluvial geomorphological processes. This analytical model offers the advantages of simplified data requirements and enhanced flexibility, making it suitable for the preliminary assessments of detailed engineering designs and field studies. This provides insights into traditional river geomorphology phenomena, explaining why riverbeds are more dynamic than static, the sediment management challenges posed by levee-oriented river management, and the persistence of concave riverbed formations near river mouths.