Completed in 1982, the Thames Barrier protects about fifty square kilometres of the City and surrounding areas from tidal surges, and to a lesser extent river floods. At the time it was a masterpiece of engineering, the second largest flood barrier in the world. Its ten steel gates were originally intended to safeguard London against circumstances perhaps arising only once in every thousand years, although climate change, increased storminess and the gradual rise of sea level as a result of ocean warming are gradually reducing this level of protection. In addition, southern England is gradually sinking as a result of tectonic readjustments after the Ice Age. The riskiest circumstances arise when an intense low pressure system over the North Sea combines with high spring or autumn tide, and high flows in the Thames basin. But flooding is a statistical function, and unusual events do occur; we cannot assume there will not be flooding within the next millennium.

Since its completion, large areas of development such as Canary Wharf have taken place below the natural flood level, making it essential that the Barrier, together with thirty seven other barriers on tributary streams and many kilometres of embankments, are maintained and continue to function effectively. The Barrier was originally expected to last until 2030, but that was subsequently revised to between 2060 and 2070. But how is this level of protection to be maintained, and what would happen if there were a structural failure or overtopping? How prepared is London, a model for other large conurbations around the world, for the truly extreme meteorological event? And what happens after 2060?

Speaker

Professor Carolyn Roberts FRGS FIEnvSc FCIWEM CEnv CWEM SFHEA is Emeritus Professor of Environment at Gresham College London, and a water and environment consultant. Her early career was as an academic at the University of Exeter, Head of the School of Environment at the University of Gloucestershire, and subsequently in Earth Sciences at the University of Oxford where she directed the national Environmental Sustainability Knowledge Transfer Network, on behalf of Innovate UK. She has been Chair of the Institution of Environmental Sciences, Chair of Society for the Environment, and is currently Fleet Warden of the Worshipful Company of Water Conservators, one of London’s modern Livery Companies.

Her research focussed on the impacts of development on rivers and groundwater in the UK, the tropics and the Mediterranean. For many years she has run her own consultancy, advising developers and local authorities on minimising damage to the natural environment, and other aspects of Environmental Impact Assessment. She was Technical Advisor to Gloucestershire County Council following the extreme River Severn floods of 2007, and has often advised the police on the movement of (dead) human bodies along rivers and canals. She continues to advise Innovate UK on grant applications for technical innovation.