The relationship between shrink–swell occurrence and climate in south-east England

Abstract

Climate change is one of the biggest environmental problems that the UK faces. Increased understanding of the impacts is vital to enable adaption to, and mitigation of, the consequences. This analysis and modelling of the relationship between climate and shrink–swell behaviour has been carried out to increase understanding of the potential consequences of changes in precipitation and temperature on ground movement in the south-east of England during the coming century.Analysis of historical climate data and comparison with subsidence claims data demonstrated the relatively close relationship of subsidence with two years’ previous precipitation. Boundaries are identified, with precipitation above 394mm for the previous two years, leading to a lower level subsidence claims, and below 350mm leading to a higher incidence. Combined with this inverse relationship, a direct relationship with temperature is identified, with a rise above 22.6°C in the mean maximum temperature for an accounting quarter leading to a peak in claims.To model a projection for susceptibility of south-east England to future climate change, UKCIP02 forecast climate data were used, and combined with the British Geological Survey national shrink–swell GeoSure geohazard dataset. Preliminary results demonstrate the most noticeable increases in subsidence susceptibility are within the areas underlain by the London Clay Formations, with other clay-rich formations also being identified, including glacial till.Despite this being a preliminary model, with large amounts of future work identified, these results are significant, providing an insight into areas of higher susceptibility and the potential for changes in ground movement for the coming century.