Wave-Induced Sediment Transport Analysis Using Hydro- and Morphodynamic Modelling in Coastal Environments

A numerical model is presented to evaluate coastal sediment transport. The model is embedded in the open-source software REEF3D. A main component to determine potential coastal erosion is the bed shear stress exerted on the sediments. The numerical model is validated for a cross-shore scenario against measurements of wave profiles and bed shear stresses induced by a solitary wave. In addition, a large-scale case of a coast located at the Baltic Sea in Estonia is investigated with regard to wave modelling and sediment transport potential.

The REEF3D framework offers a 3D hydrodynamic model with a water- and air-phase REEF3D::CFD as well as a surface and bottom following non-hydrostatic sigma-grid model REEF3D::NHFLOW. Both models are coupled with a morphological module. This investigation shows the applications of both approaches with regard to prediction of waves reaching the shoreline, where they deform, shoal or break depending on the bathymetry. The wave-induced flow at sloping beaches leads to morphological changes. Erosive and aggregative conditions are important to assess in order to identify problematic zones and ensure proper coastal management and engineering.

The validation of the model against solitary wave experiments demonstrates its capability to accurately predict the wave dynamics and resulting bed shear stresses, which are crucial for understanding sediment mobility. For the Baltic Sea case study, the model successfully simulates wave transformation and sediment transport potential under various hydrodynamic conditions, showcasing its versatility for real-world applications.

This work highlights the importance of numerical modelling in coastal engineering, offering insights into sediment dynamics and the impact of hydrodynamic forces on coastal morphology. By leveraging the open-source capabilities of REEF3D, the study provides a framework that can be adapted for diverse coastal environments. The integration of detailed hydrodynamic and morphological modules allows for the comprehensive analysis of sediment transport processes, enabling effective decision-making for coastal protection and sustainable management strategies.