Percorrer por autor "Uddin, A S M Shanawaz"
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- Vegetation and platform geometry effects on wake attenuation in wetlandsPublication . Uddin, A S M Shanawaz; Carrasco , A. Rita; Fernández, María E. MazaWetlands play a vital role in coastal protection by dissipating wave energy, reducing flooding risks, stabilizing shorelines, and offering sustainable alternative to engineered defenses. Despite extensive research on wind wave attenuation by salt marsh vegetation, further studies are needed to quantify wetlands ability to mitigate the impact of wind and boat generated waves, and enhance their use as a Nature-based Solution towards sustainable coastal protection strategies. The aim of this study was to investigate the role of wetlands vegetation and morphology in dissipating wave energy in the Ria Formosa lagoon, southern Portugal. This was accomplished through a comprehensive analysis of how vegetation characteristics and profile morphology influence wave attenuation, utilizing field measurements and numerical modelling. Specifically, after understanding physical mechanisms and validate the SWAN model, this model was employed to assess the effects of different boat wake intensities, vegetation densities, and platform geometries on wave energy reduction. The results obtained demonstrate that wetland platforms with gentle slopes and around 100 meters length seemed to be the most effective on reducing wave energy, but they only contribute to 10% of the overall wave attenuation, with the remaining attenuation being promoted by the vegetation. Densely vegetated profile achieved 68% wave energy reduction compared to sparse or non-vegetated ones. Zostera noltei provided greater attenuation than Spartina maritima at only higher wave heights. Nevertheless, the occurrence of mixed-species vegetation proved to be more effective than just having single vegetation, for the same geometry. Wave attenuation increased with both wave height and vegetation density, up to a saturation point at around 4800 stems/m2 for Zostera noltei and 1400 stems/m2 for Spartina maritima. These findings suggest that optimizing both biological and platform characteristics is essential for maximizing coastal protection. The research highlights the need for comprehensive field measurements, with diverse ecological settings, tidal dynamics, varied geometries and salt marsh species to more effectively capture complex interactions between waves and wetland ecosystems. The outcomes provide practical recommendations for designing and managing resilient wetlands to support sustainable and adaptive coastal defense strategies.