Wave and Tidal Hydrodynamics Characterization of Montrose Bay: A Severely-Eroding Coast in East Scotland

By 2050 under the predicted climate change high emission scenario, 75% of the soft coastline in Scotland will be susceptible to erosion, including the coastline at Montrose Bay, East Scotland. This paper aims to characterize the prevailing wave and tidal regimes of Montrose Bay and assess their potential role in the coast's dynamics. The numerical modelling presented here comprised of a flow and wave model developed using Delft3D-Flexible Mesh. In the coupled model's calibration against an ADCP measurement, roughness, viscosity and boundary conditions are tuned. Additionally, the Coast XRay data is used to generate the intertidal elevation for Montrose Basin, and this produced a significant improvement to the model. The model produced a satisfactory result when validated against the observed water level, current velocity, and wave parameters. Flood-ebb flow, residual current, and waves during August 2015 are discussed. A southward residual (of 30 cm/s) is observed at Glaxo Beach Frontage and Annat Bank which is likely to induce a net southward transport and this is expected to be one of the responsible factors for the sediment filling at Montrose Port's channel. Further, beach sections along the coastline see distinctive wave climates. Going northward along the coast, the wave height is increasing and its direction rotates clockwise. The oblique wave and the alongshore wave variation are likely to generate a strong longshore current that will distribute beach sediment along the coastline.