INVESTIGATING THE RECESSION PROCESS OF COMPLEX SOFT CLIFF COASTS: AN ISLE OF WIGHT CASE STUDY

Abstract

Understanding future retreat rates of soft rock cliffs is important for a range of coastal management activities, particularly when considering the impacts of climate change. One key method is process-based numerical modeling. However, this technique is still in its early stages and consequently the process of cliff recession is typically over-simplified. This paper reviews the application of the SCAPE (Soft Cliff and Platform Erosion Model) to a varied geological frontage on the south west coast of the Isle of Wight. Evaluation of the 2D model has been undertaken through validation of the output model profiles compared with measured and field data observations. The results have identified the importance of vertical variations in rock strength within the cliff system, which has a strong influence on recession rates, cliff morphology and the development of emergent features. Evaluation of the model has also highlighted the importance of translating cliff base retreat into an appropriate cliff top position, which defines the extent of the erosion hazards, and hence is of more practical use (e.g., land-use planning). This requires more consideration of the role of terrestrial processes within the cliff recession process.