Abstract
Saltmarshes are considered as natural coastal defences. However, owing to the large context dependency, there is much discussion over their effectiveness in providing coastal protection and the necessity of additional coastal defence interventions. The macro-tidal Taf Estuary in south-west Wales was chosen as the case study in this paper to investigate the effects of anthropogenic coastal defence interventions such as construction of hard defences, managed realignment, and altering land use of the saltmarshes on the complex hydrodynamics of the estuary. A coupled flow–wave–vegetation model, developed using the Delft3D coastal modelling software, was used. The wave and current attenuation role of saltmarshes during two contrasting storm conditions was modelled, with and without saltmarsh management interventions. The study reveals that certain saltmarsh management interventions can have widespread impacts on the hydrodynamics of the estuary. Altering the land use by allowing extensive grazing of saltmarsh by livestock was found to have the largest impact on wave attenuation, where wave heights on the marsh almost doubled when compared with the no-intervention scenario. On the other hand, managed realignment has a significant impact on tidal currents, where tidal currents reached 0.5 m/s at certain locations. Changes in estuarine hydrodynamics can lead to undesired impacts on flooding and erosion, which stresses the importance of understanding the effects of localized anthropogenic coastal management interventions on the entire estuarine system.
Highlights
The sustainability of coastal defence practice in the United Kingdom and elsewhere is under increasing scrutiny owing to growing costs and the implications of global climate change
We investigate the effects of three fundamentally different flood mitigation intervention strategies on hydrodynamics of the Taf Estuary, located in south-west Wales, United Kingdom, during extreme storm events through a computational modelling study
We use computational modelling to investigate the impact of management intervention scenarios on the flood mitigation function of saltmarshes of the Taf Estuary and wider hydrodynamic regime of the Taf Estuary
Summary
The sustainability of coastal defence practice in the United Kingdom and elsewhere is under increasing scrutiny owing to growing costs and the implications of global climate change. Saltmarshes have been found to act as natural buffer zones, providing protection from storms and flooding [1]. Saltmarshes have been demonstrated to be more effective at providing wave damping [3,4,5]. Saltmarsh vegetation has been shown to reduce wave setup [9] and alter the flow velocity profiles within the marsh and beyond [10,11,12]. These effects in turn can alter sediment dynamics, contributing to coastal morphodynamic evolution [11,12,13]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
