Numerical modelling studies to predict the potential impact on the sediment transport of a proposed Outer Harbour at Great Yarmouth, UK

摘要

An outer harbour is proposed to be constructed on the east coast of England at Great Yarmouth. As part of a series of studies during the planning stage HR Wallingford were commissioned to investigate the potential impact of the harbour on the adjacent sediment regime. A combination of models was used to simulate the sediment transport processes on the existing coast, and involved a comprehensive simulation of the littoral drift at strategic locations, and two-dimensional area modelling covering some 20km of the coastline and extending 10km offshore. A particular feature of this study was the requirement to simulate the effect of the complex and mobile offshore sand banks in modifying the propagation of waves from offshore to inshore and the associated effect on the littoral regime. A key aspect of any project of this scale is the need to verify relevant aspects of the model, in order that the greatest confidence can be given to the model's predictions. For this study information was gathered from a number of sources for use in verifying the wave propagation, tidal current, and littoral drift models. Simulation of the post-construction scenario highlighted the magnitude and extent of the potential impact of the harbour on the littoral drift, particularly with respect to the beaches immediately to the south. A series of sensitivity tests were performed to assess the natural variability in the littoral drift due to both the offshore wave climate and the configuration of the offshore sand banks.