Estuarine bankline erosion processes and coastal retreat in the Severn Estuary, UK

Rising sea levels and increased storminess due to climate change pose significant risks to coastal communities and infrastructure. As well as increased flooding, coastal erosion is likely to increase. The heads of estuaries are particularly at risk but, unlike open-coasts, estuarine susceptibility to erosion is not well-researched. For example, the Severn Estuary, UK, experienced extensive head-of-estuary flooding in recent years and is characterised by erodible margins but nothing is known as to likely future changes in the bank lines. Relative to river-bank erosion, erosion of estuarine banklines has received relatively little attention. In contrast to river-banks, estuarine banklines often are subject to periodic reversing flows, very rapid changes in groundwater pressures due to tidal movement and the impacts of wind-waves related to storm frequency. This project will combine cutting-edge survey technology from Geography and Environment’s Environmental Sensing facility (www.esas.soton.ac.uk), such as laser scanning technology, along with field sampling to feed key data into a state-of-the-art bank erosion modelling framework for the Severn estuary. Key aspects will include consideration of sedimentology, stratigraphy, groundwater monitoring and basal end-point control. Novel aspects include the hypothesis that the rates of estuarine bank erosion exhibit cyclicity in response not only to the semi-diurnal tides (M2 tides) but also to other tidal components such as the equinoctial cycle. Such cyclicity may be over-printed by wind-wave erosion, river discharge and weather-controlled processes, but the relative importance of these controls is unknown. An additional novel aspect, therefore, will be to monitor river discharge, wind-wave activity, seasonal and long-term vegetation changes and the conditioning of the bank profile by the effects of biological cohesion by drying and wetting cycles affecting mud drapes. A generic model would be transferable in principle to other estuarine locations.


Further details about our research group, Earth Surface Dynamics, are available on our web pages:

http://www.soton.ac.uk/geography/research/groups/earth_surface.page?

Candidates must have or expect to gain a first or strong upper second class degree, in an appropriate discipline, not necessarily Geography. Details on how to apply are available from Julie Drewitt, email [Email Address Removed]. Informal enquiries may be made to Julian Leyland (email [Email Address Removed]). For the latest information on postgraduate opportunities within Geography and Environment, please visit our website at http://www.southampton.ac.uk/geography/postgraduate/research_degrees/studentships.page?