University of Bath

Coastal protection and near-shore evolution under Sea Level Rise

This project will refine knowledge on coastal dynamic and shore evolution prediction, helping society to adopt sustainable and resilient coastal defences.

Photo of the revetment tested in the large scale flume
The revetment being tested in the large scale flume

The objective of this project is: 1) To get a better understanding of coastal and near-shore processes ruled by erosive waves and sea level rise. 2) To design, test and analyse the performance of a dynamic revetment – new kind of protection falling into the ‘work with nature’ category.

Project outline

Global mean sea level is rising at increasing rate, and this represents one of the main long term coastal hazard. Existing hard engineering coastal defences are neither designed nor efficient against Sea Level Rise (SLR), and therefore are likely to be overtopped and breached during this century.

A recent soft engineering technique named “dynamic revetment” or “cobble berm” has been implemented in some coastal places to protect the hinterland against storm waves and erosion. This type of revetment is not static and moves under waves’ action while dissipating the waves’ energy. By optimising the design of the dynamic revetment as well as the deployment area, this structure is supposed to self-maintain its relative position to sea level under SLR. The pebbles composing such a protection are expected to move landward under SLR, thus keep protecting the hinterland against future extreme wave climate.

The performance of the revetment was tested in the GWK large scale flume, Hannover, Germany, through the ‘DynaRev’ experiment. The experiment was designed to assess the behavior and the capacity of the revetment to adapt and protect sandy beach against waves attack and SLR. The experiment was also designed to provide a large range of morphodynamic data required for a better understanding of general coastal processes under SLR.

Science

The laboratory experiment undertaken during this project provided a large and unique dataset on beach profile evolution and dynamic revetment behaviour under sea level rise, erosive and accretive conditions. This project will help validating or modifying the commonly accepted statements on sandy and composite beach profile evolution. It will also be a strong scientific base regarding to the performance of a dynamic revetment, and eventually lead to field application.

Impact

This project will have an impact on fundamental coastal science as it will refine the knowledge on coastal dynamic and shore evolution prediction. On the other hand, it will offer a designed and tested structure to protect small asset and habitat from storms and sea level rise. Therefore, through local decision taker, it could help the society to adopt sustainable and resilient coastal defences.

This is the PhD project of Paul Bayle from the Department of Architecture and Civil Engineering. Email address: P.M.Bayle@bath.ac.uk