Abstract
Abstract. Sea-level rise (SLR) not only increases the threat of coastal flooding, but may also change tidal regimes in estuaries and coastal bays. To investigate such nearshore tidal responses to SLR, a hydrodynamic model of the European Shelf is downscaled to a model of a Dutch coastal bay (the Oosterschelde, i.e., Eastern Scheldt) and forced by SLR scenarios ranging from 0 to 2 m. This way, the effect of SLR on tidal dynamics in the adjacent North Sea is taken into account as well. The model setup does not include meteorological forcing, gravitational circulation, and changes in bottom topography. Our results indicate that SLR up to 2 m induces larger increases in tidal amplitude and stronger nonlinear tidal distortion in the bay compared to the adjacent shelf sea. Under SLR up to 2 m, the bay shifts from a mixed flood- and ebb-dominant state to complete ebb dominance. We also find that tidal asymmetry affects an important component of sediment transport. Considering sand bed-load transport only, the changed tidal asymmetry may lead to enhanced export, with potential implications for shoreline management. In this case study, we find that local impacts of SLR can be highly spatially varying and nonlinear. The model coupling approach applied here is suggested as a useful tool for establishing local SLR projections in estuaries and coastal bays elsewhere. Future studies should include how SLR changes the bed morphology as well as the feedback effect on tides.
Highlights
Sea-level rise (SLR) poses an increasing flood risk on global shorelines (FitzGerald et al, 2008; Haigh et al, 2014)
The errors of observed and modeled M2–M4 phase difference (2φM2 − φM4) are −6.2, 13.5, and 21.3◦ at Roompot binnen, Stavenisse, and Bergse Diepsluis west, respectively (Fig. 3b), which may result from the meteorological forcing and gravitational circulation that is lacking in the model
The model overestimates the extent of flood and ebb dominance, but the direction of tidal asymmetry agrees with the observation (Fig. 3b)
Summary
Sea-level rise (SLR) poses an increasing flood risk on global shorelines (FitzGerald et al, 2008; Haigh et al, 2014). In addition to the direct increment in water levels (Church et al, 2013; Oppenheimer et al, 2019), SLR induces changes in global and regional tidal regimes (Pelling et al, 2013b; Devlin et al, 2017; Pickering et al, 2017). Understanding these tidal changes is an imperative step towards projecting future water levels and designing shoreline protection works (Katsman et al, 2011; Haasnoot et al, 2019). In order to understand and mitigate the SLR hazards in estuaries and coastal bays, it is of high priority to study the SLR impact on tides
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
