The morphodynamic evolution of coastal flood risk: Investigating the role of clay in modulating coastal cliff erosion

Supervisory team: Dr Chris Hackney ([Email Address Removed]); Dr David Milan; Prof Dan Parsons; Dr Georgie Bennett (UEA).

Coastal cliff retreat is a serious problem threatening coastlines worldwide, with a range of implications for flood risk. In the UK alone, estimates of future economic losses due to the coastal erosion expected under future climate change are >£120 M per year. Understandably, there is therefore an interest in developing robust predictive models that identify rates and locations of likely retreat. In soft-cliff environments, much research has focussed on the role of wave energy, modulated by tides, as a key driver of coastal erosion. Comparatively little attention has been given to role of subaerial processes (i.e. those not driven by waves and tides) in coastal erosion, although these may play an important role in driving cliff retreat, both directly (i.e. through slope failure) and indirectly (i.e. through weakening cliffs and making them more susceptible to wave erosion). Soft cliffs are characterised by unconsolidated material comprised of sands and clays in varying proportions. Clay acts as a cohesive agent but also tends to crack and weaken in response to fluctuations in soil moisture. Future climate projections for the UK suggest the increasing probability of warmer, drier summers and wetter winters (ASC, 2016). This increased climate variability is likely to have significant impact on the subaerial cliff erosion especially where clay content is high, making it important to constrain the role of clay in modulating coastal erosion.

This PhD project will use state-of-the-art, high resolution methodologies to capture concurrent changes in cliff morphology and soil moisture with which to understand the role that clay content plays in modulating soft-cliff erosion. It will assess the role of soil moisture fluctuations in driving cliff erosion and will quantify, for the first time, the contribution of sub-aerial erosion to coastal retreat as a function of clay content. Using observed process data, new models of coastal retreat will then be developed that are capable of capturing holistic coastal erosion process and assessing the role of climate change on rates of soft-cliff retreat.

Closing date will be the 4th of August, with interviews scheduled for the 16th August.

For informal queries please contact: Dr Chris Hackney ([Email Address Removed]).

Planned start date: 1st October