Modeling Coastal Morphological Features in Proximity to Breakwaters Using Delft 3D

Abstract

Coastal areas are crucial hubs within metropolitan regions, supporting diverse commercial and leisure activities. However, these ecosystems face threats from escalating natural calamities like storms and floods, disrupting local wave patterns and altering beach structures. Despite these challenges, the allure of coastal living fuels continuous urban expansion in these regions. To combat shoreline retreat caused by factors such as high tides, insufficient sediment movement, and strong waves, various protective structures are deployed. These measures aim to alleviate or prevent coastal erosion, although many were constructed without considering their environmental impact, economic implications, maintenance costs, or the potential widespread damage along the coastline. The strategic use of detached breakwaters as coastal defenses triggers changes in tombolo formations. This study explores the application of a Delft 3D model, a process-based tool, to examine the evolution of these morphological features, using a defined model domain from a prior case study. After conducting sensitivity analyses with optimized parameters like facua (set at 0.1), Chezy coefficient (at 60), and directional energy distribution, the model's outcomes are compared against empirical models. The Delft 3D simulations demonstrate the development of tombolos and salients 500 meters offshore after a 30-day simulation period for breakwaters positioned at distances of 150m, 200m, and 500m from the shoreline. This numerical analysis employing the Delft 3D model has enhanced our understanding of how the offshore distance of breakwaters impacts the evolution of coastal features such as tombolo and salient