Author(s): Francisco V. C. Taveira Pinto; Paulo Rosa Santos; Francisco Taveira-Pinto; Luciana Das Neves; Victor Ramos

Linked Author(s): Francisco Taveira Pinto, Paulo Rosa-Santos

Keywords: Delft3D Flexible Mesh; Sandspit; Unstructured mesh; Morphological changes

Abstract: This study aimed to analyze the hydrodynamic and morphodynamic trends in the vicinity of the northern end of Ofir sand spit, located in the mouth of Cavado River, Portugal, with and without the implementation of new coastal protection structures. The simulations without the new structures showed a narrowing of the navigation channel, silting up of the channel, and northward movement of the sand spit's end towards the navigation channel. The study also found that periodic dredging was necessary to ensure the minimum required depth for navigability and access to the marinas and fishing ports inside the estuary. The implementation of the new coastal protection structures, including a longitudinal dike and two detached breakwaters, led to sediment transport towards the lee side of the detached breakwaters, contributing to sediment reinforcement of the Ofir sand spit over time. Moreover, the longitudinal dike prevented the sand spit from moving towards the navigation channel, and the depth of the navigation channel remained relatively constant during the simulations. The study also found that the main sediment input to the lee side of the detached breakwaters occurred between the longitudinal dike and the first detached breakwater. This study highlights the importance of coastal protection structures for maintaining navigability and preventing shoreline erosion. It also emphasizes the potential benefits of such structures for sediment management and beach nourishment. The findings of this study can contribute to future coastal management and protection plans in the Cavado river mouth and other similar coastal systems.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0991-cd

Year: 2023