Bio-hydromorphology integration model establishment and validation based on 10-year-span field observations and its application to flood management

Human interventions such as channel excavation and tree cutting present substantial challenges to effective riparian ecosystem management. The prediction of hydrogeomorphology–vegetation interactions and assessment of management effectiveness require a comprehensive model. However, many existing models rely on simplified or idealised conditions, limiting their applicability to real river systems. To address this, the present study developed an integrated bio-hydromorphodynamic model to simulate and predict interactions among riparian vegetation dynamics, hydrodynamics, and morphodynamics in real river systems and evaluated its practical application in assessing the long-term effects of river management strategies on flood capacity improvement. A depth-averaged two-dimensional model was employed for hydromorphodynamics, and riparian vegetation dynamics were simulated based on annual processes of recruitment, growth, expansion, and flood-induced destruction. Comparative analysis of the model results with 10-y observational data on vegetation distribution and riverbed evolution from the Kumozu River, Japan, verified its accuracy and applicability, with the simulated and observed results demonstrating strong consistency. The validated model was then applied to assess the effectiveness of different river management strategies for restoring flood capacity. These findings underscore the importance of long-term impact assessments in river management planning, highlighting the potential of the model as a decision-support tool for sustainable river management.