Experimental and Numerical Modelling Study of Swash Zone Hydrodynamics and Sediment Transport

The swash zone is that region of the beach alternately covered by flow uprush and backwash following wave-breaking. It is a highly dynamic environment with flow velocities frequently exceeding 2 m/s. Vast quantities of sediment are transported up and down the beach by uprush and backwash, and the difference between the upslope and downslope transport determines whether a beach will erode or accrete. The swash zone is sometimes referred to as the 'biting edge of the sea', because it is here that shoreline erosion is manifested. The aim of the research is better understanding of fundamental swash processes and the development of a model for predicting hydrodynamics and sediment transport in the swash zone.The research involves detailed laboratory experiments conducted at large-scale and designed to isolate and measure the key processes. Results from the experimental work are used to improve and extend an existing swash numerical model to predict flow, sediment transport and morphological change for given beach and incident wave conditions. The focus of the research is on relatively steep beaches, with slopes of order 1:10 and comprising relatively coarse material with grain size greater than 1mm. The research contributes to establishing well-founded models for predicting beach response to wave action. Such models are vitally important in the context of coastal design and coastal zone management.