Author(s): Xihang Xu; Md Salauddin
Linked Author(s): Md Salauddin
Keywords: No Keywords
Abstract: Recently, seagrass canopies have been increasingly prioritised as a Nature-based Solution (NbS) for coastal resilience because of their dual benefits of ecological enhancement and wave energy dissipation. Numerous studies have evaluated seagrass-induced wave attenuation over the past few decades, but most focus on idealised, continuous canopies, thereby neglecting the spatial heterogeneity that characterises natural ecosystems. To bridge this gap, this study conducted a series of laboratory wave-flume experiments using scaled artificial seagrass mimics of Zostera marina under irregular wave conditions. This study quantified the hydrodynamic impact of two key parameters: canopy fragmentation (reduction in biomass) and longitudinal gap spacing between two independent seagrass canopies. It was found that canopy fragmentation can significantly compromise wave attenuation, particularly under low submergence-ratio conditions. A fragmentation level of only 12.5% resulted in an average 78% reduction in attenuation. Longitudinal spacing demonstrated a non-linear relationship with wave attenuation. While large gaps were expected to reduce performance by 9.4%-29.3%, smaller gaps resulted in a net increase in attenuation of 4.5%-5.6%. This counterintuitive enhancement can be attributed to the dominance of edge-induced turbulence over flow recovery within the gaps. The findings from this study contribute to the optimisation of the spatial design of seagrass restoration projects and, in turn, to the development of a sustainable coastal protection strategy.
Year: 2026