Quantifying the Impact of Extreme Storms on Slope Erosion: Improving our Capacity to Forecast Erosion Hazards

We are already experiencing the impacts of climate change. In recent years, more intense storms, particularly in northern, central and eastern Europe, the Americas and South and East Asia, have led to an increase in extreme erosion events. For example the tails of Atlantic hurricanes have hit Europe for the first time (e.g. Storm Eleanor, Storm Eberhard). The impact of these erosion hazards are of global importance because they are wide ranging, costly and of critical importance to the vulnerability of assets. During the last 50 years nearly one-third of the world's arable land has been lost by erosion, causing an annual cost to global GDP of $8BN. In the UK for example, erosion causes £336M a year in extra flood damage, are a considerable source of water pollution totalling costs of £238M a year, and increase the costs of water treatment and maintenance of drainage networks by £132M a year. They cause considerable damage to critical infrastructure such as roads and electricity pylons, and account for 25% of valid subsidence insurance claims. In Fukushima, erosion is the major cause of wash-off of radiocaesium to rivers and streams, and ultimately to the Pacific Ocean. Thus creating resilient, sustainable infrastructure depends on accurate prediction of the future risks of more extreme erosion hazards. Yet at present, soil erosion models for river catchments perform poorly in predicting erosion rates in extreme, high intensity storms.

Japan has been experiencing these types of storm events for many decades, predominantly during the monsoon season, (the so called "guerrilla rains") e.g. Typhoon Hagibis during the Rugby World Cup caused damage totalling >$15BN and killed 98 people. The Japanese National Research Institute for Earth Science and Disaster Prevention and the University of Tsukuba has world-leading laboratory and field infrastructure to monitor the impacts of these events on erosion. This project brings together the highly complementary expertise of these partners with the state-of-the-art modelling tools at the University of Liverpool. Through a set of novel, integrated field, rainfall-simulation and numerical experiments, the partnership will produce novel understanding of the controls of erosion dynamics in high intensity rainfall, and the development of more realistic models that will enable global scientists to better forecast the impacts of extreme erosion events. Together we will develop the ideas, datasets and modelling tools to facilitate a major step-forward in understanding high-magnitude erosion events, both through the direct activities of this proposal, and by creating a long-lasting partnership.

The outputs will include:
- Scientific insights into erosion during extreme, high rainfall intensity storms, and how this might change as a result of climate projections
- A quantitative predictive modelling framework that provides much needed accurate forecasts of erosion hazards, that can be applied to assess future erosion risk to critical infrastructure
- A long-lasting world-leading partnership in erosion monitoring and prediction, and a spring-board for new links and scientific discovery with global researchers