Development of an Integrated Model to Determine the Impacts of Climate Change on Coastal Recession

1. Development of an Integrated Model to Determine the Impacts of Climate Change on Coastal Recession 1) Problem Statement Soft rock cliffs create geomorphologically diverse coastlines owing to the complex interactions between geology, combined with the applied forces of marine and terrestrial processes. They are highly susceptible to recession and one key challenge is to understand how climate change aspects (e.g. sea-level rise, increased seasonal rainfall) will alter this process. As such, traditional methods to predict recession (by extrapolation of historic rates) should no longer be considered acceptable when past conditions are not representative of the future. In response one alternative method is process-based numerical modelling, which enables system changes and process interactions to be simulated. However, this method is relatively in its infancy and many models are criticised for the generalised manner in which they treat cliff behaviour. This relates to the key assumption that it is coastal processes that drive recession. This may be problematic for complex cliff sites, potentially leading to inaccurate future predictions of cliff-top position if the effect of climatic factors on slope stability are omitted. 2) Research Description The aim of this study is to develop a coupled, process-based model which considers the influence of both coastal andslope (geotechnical) processes on soft cliff recession. The model will be developed considering the complex study frontage of the south-west coast of the Isle of Wight, UK (Figure 1). Figure 1: Isle of Wight Study Frontage This 17km site has a varied soft rock geology, exhibiting a series of headlands and a range of cliff behavioural units. Therefore, it provides strong opportunities to validate the more integrated coastal cliff recession model than those currently available. 3) Preliminary Results Considering the complexity of the cliff recession process, the first stage has been to develop a generalised conceptual model (Figure 2) to understand all systems, parameters and processes involved in the cliff recession process. This highlights the plethora of interactions and feedback mechanisms within the cliff system and subsequently will form the foundation for the development of the numerical model. Figure 2: Generalised Conceptual Model of Soft Cliff Coastal Recession Contact: Natasha Carpenter (PhD student) Civil Engineering and the Environment nec1v07@soton.ac.uk, www.southampton.ac.uk