Numerical modeling for low-frequency wave-induced flows over wooden fences

Abstract

Coastal areas along the Mekong Delta have faced a massive reduction of mangroves and have been slighlty returned due to the impact of nature-based solutions, especially the vital role of wooden fences. In this study, the role of low-frequency wave-induced flows and shear stress is assessed by the open-source model, SWASH (Simulation WAve till SHore, developed at Delft University of Technology). Modeling results are simulated using the data records in two monsoons, the southwest and the northwest, to assess firstly the model accuracy. This result shows a good agreement between the SWASH model and field data, which is presented for incoming wave heights. However, there is a slight mismatch between the simulated results and transmission records due to the higher density of fences in SWASH in comparison to the field. Last but not least, the longwave-induced flow results indicate the potential for increasing the sedimentation rates behind the fences since longer waves are less damped than shorter waves. As a result, the flow driven by longwaves has enough energy to bring sediments over the fences.