Natural Hazards Research Summit 2024: Computational Wave Loads on an Idealized Near-Coast Structure Behind Nature-Based Protection

Climate change and its adverse impacts, such as rising sea levels, have intensified the risk of extreme flooding in coastal communities. These events significantly exacerbate the risks faced by near-coast structures and the communities that inhabit these regions. Coastal wetlands are known to play a crucial role in natural flood reduction, yet their precise impact on flood dynamics during extreme weather events remains underexplored. Specifically, their role in reducing flood loads due to surges and waves on near-coast structures requires more research. To shed light on the extent to which aquatic vegetation reduce wave loads, two computational fluid dynamics (CFD) models were employed. Using NHWAVE and Flow-3D as high-resolution CFD models offers a unique approach to understanding the complex interactions between wave dynamics and coastal vegetation and evaluate the suitability of each model, which resolve physics and different degrees, for computing wave loads. It was observed that both models effectively capture load trends and peak values. NHWAVE and Flow-3D compare well under non-breaking wave conditions, and for breaking wave conditions, the simulated peak load using NHWAVE is close to that of Flow-3D. Additionally, it was found that increases in stem density, rigidity, and height result in a reduction in wave loads. The findings of this study can be utilized by a broad audience, including coastal engineers, environmental scientists, urban planners, and policymakers to advance sustainable coastal management and climate adaptation.