Morphological model of the river Rhine : partially calibrated (v0.5) model of the Waal branch

The Rhine riverbed is dynamic, influenced by morphological processes and human intervention. The current DVR model for predicting morphodynamics is outdated due to: 1. Calibration based on periods before key interventions (Room for the River, Water Framework Directive). 2. Transition to new software (6th generation models in the D-HYDRO Suite). 3. New data and insights on morphological developments. A new model is being developed, starting in 2023, with progress reported for 2023-2024, resulting in model version v0.5. The final model will be fully described in a future report. In 2023-2024, the first version of the Waal morphological model (v0) was set up using existing hydrodynamic models, with improvements made in 2024 leading to version v0.5. These changes improved numerical stability and reduced simulation times. The model includes fairway maintenance and sediment extraction, validated against reported volumes and dune heights. Analyses of model results focused on downstream boundary conditions, fixed layer roughness, and sediment transport parameters. The selected parameters for 1D calibration showed lower sediment transport than previous estimates. The final model, to be set up in 2025, aims to match sediment transport from Boven-Rijn.