The Centre for Coastal Processes, Engineering and Management (http://www.ccpem.soton.ac.uk/) has been established to develop coastal research at the University of Southampton, including education, research and consultancy. Wider engagement with users has been started with a new coastal lecture series. The inaugural lecture was introduced by Professor Robert Nicholls (co-director of CCPEM) and given by Professor William Allsop (HR Wallingford) who holds a visiting chair in the School of Civil Engineering and the Environment.
The lecture was entitled ‘Coastal engineering in the UK (and further afield): where are we going and will we get there?’. Professor William Allsop presented a wide-ranging and chronological review of coastal engineering and future needs, with an emphasis on hard engineering, particularly breakwaters and seawalls. A number of themes and arguments permeated the lecture, including a range of technical, social and educational issues. The key points are summarised below.
The first theme was that historic coastal development patterns have left us with significant coastal vulnerability that is difficult to manage with the present climate, and these difficulties will only get worst through the twenty-first century. Society has a long history of advancing the line—building infrastructure out into the sea with an ongoing requirement for coastal protection and engineering. In many cases, to quote Professor Allsop, ‘Some of this is simply mad!’. Whereas many in the UK seem to recognise these conundra and are at least trying to limit this vulnerability, globally coastal development continues to expand in vulnerable areas. Examples include substantial estuarial land claim in South Korea and coastal reclamations in the Persian Gulf, especially Dubai. Professor Allsop observed that maybe the UK will be able to provide advice as the problems that we recognise so well today become more widely recognised. Extending assessments such as the Foresight Flood and Coastal Defence study1,2 to include risks to critical coastal infrastructure such as power stations and oil refineries would help us to mitigate unlikely (but not impossible) future situations that might be quite threatening to the UK economy and more widely.
Despite Professor Allsop’s view that coastal development needs careful planning which takes account of coastal processes, he observed the paradox that people living in threatened areas often prefer hard defences to the softer flood and erosion management techniques that are increasingly advocated. Given that threats are likely to get worse, this represents a major challenge. To address this issue, the need for education of policymakers and the wider range of stakeholders was repeatedly emphasised by Professor Allsop.
To get the most out of our existing coastal infrastructure we need to improve our understanding of the performance of coastal defences and present this in useful ways for coastal engineers. We also need to understand where processes are complex, and use the right level of knowledge and experience. The example of wave overtopping was presented. Many engineers regard this process as relatively well-understood. It is, but only by a limited group of experts. Most empirical formulae for overtoping are monotonic—that is, they predict diminished overtopping as water levels fall (or the defence crest is raised). Sadly, for some defence types, empirical data show this is not what occurs in practice. For vertical (or steep-faced) seawalls, wave breaking may increase as the water level falls, and overtopping (both volumes and violence) may increase dramatically.3 Professor Allsop argued that while research often develops elegant solutions, publication of research may be obscure and difficult to find, and so the results are often slow to be transferred to practice, and this issue requires attention.4 The risks to people of overtopping also deserve much more attention as roughly two to four people are so killed each year, but this increased to 11 people in 2005. This hazard is underrated probably because it does not capture newspaper headlines, and yet with focused multi-disciplinary research this death toll could be reduced, and future tragedies avoided.5
Although our understanding of overtopping and general wave loadings on coastal structures has improved,6,7 much research remains to be done on consequential loadings. Sadly, many designers seem to use rather simplistic or outdated tools. More work is needed to communicate the need for the right skills and tools for the job.
The discussion focused around the role of low-probability, high-consequence events. Professor Carl Amos observed that they could be catastrophic for coastal society as shown by Hurricane Katrina. This supported Professor Allsop’s call for low-frequency events to be systematically analysed and considered in policy analysis. Whereas this discussion started with flood events due to surges, tsunamis were also considered. Although this hazard seems of limited concern to the UK, the difficulties of ascribing risks were emphasised.
At the conclusion, Professor Nicholls led a vote of thanks for an entertaining, informative and stimulating talk.
