17 December 2014, 3.00 PM - 17 December 2014, 4.00 PM
Seminar Room 1, School of Geographical Sciences
Dr Ivan Haigh, University of Southampton (NOC) will present this Physical Geography Seminar Series talk.
Coastal flooding can be devastating, with long-lasting and diverse consequences. The UK has historically suffered major (and deadly) coastal flooding events including those of 1607, 1703 and 1953, the latter being pivotal in prompting improvement of risk management practices. However, the continued threat of serious coastal flooding was apparent during winter 2013–2014 when the UK experienced a series of storm surge and wave events. What is noteworthy about the 2013-14 winter period is the: (1) large number of exceptional high waters and coastal floods over a relatively short time period; and (2) the large number of coastal regions affected. Extreme events are rarely assessed in terms of temporal ‘clustering’, despite the fact that ‘repeated shocks’ to defences and communities can reduce time for recovery and lead to amplified flood damages. The spatial dependence or ‘footprint’ of flood hazards (i.e. simultaneous flooding in multiple locations) is also receiving more attention, motivated by concern from re-insurance, infrastructure reliability and emergency response, and because the understanding of this is currently limited. Here we assess how unusual the 2013-14 storm surge season was in the last 100 years, in terms of both temporal ‘clustering’, and the spatial ‘footprint’ of events. To do this we analyse sea level records at the UK’s 44 national tide gauge sites, and use a threshold of the 1 in 5 year return period (at each site) to select high waters that are potentially relevant to flooding. Using meteorological re-analysis data, we determine storms tracks and characteristics that generated these extreme sea level events. In total, we 99 events that generated water levels greater than the (1 in 5 year return period) threshold (which for consistency, is a level which is also offset for mean sea level change). For each event, the time to the next nearest event is calculated and the spatial footprint estimated. This is compared for all years on record. Finally, we consider how to improve estimates of extreme sea levels using advanced statistical methods that can represent event clustering and footprints; in order to provide stakeholders with tools to improve how coastal flood risk is identified, assessed and planned for.
Open to all UoB staff and students.