ENFORCE - Extreme responses using NewWave: Forces, Overtopping and Run-up in Coastal Engineering

In the UK there is a significant amount of infrastructure located at or close to the coast, some of it highly vulnerable to relatively small wave events as well as extreme storm events. Most published coastal studies, and hence guidance documents, are based on the prediction of average quantities such as overtopping rates per hour. Whilst these are undoubtedly useful for estimating drainage requirements and for making flood predictions if the inland drainage is inadequate or becomes blocked, they give little insight into the damage that may be caused by a single extreme overtopping or impulse event, which could cause global structural failure of sea defence works.

This project addresses the problem of the most extreme responses at the coast, whether this is wave run-up, overtopping volume or impulse on a section of sea defence works. We aim to understand and model the individual largest and most damaging waves within a long random sequence of severe waves hitting the coast - a storm consisting of thousands of individual waves. We will use the idea of localised groups of large waves to model the most severe waves that arise by chance in a storm. Detailed comparisons will be made between waves in the new flume at Plymouth University and a recently developed computer model OXBOU, all underpinned by analysis of waves at 2 locations off the British coast.

How will the impacts be achieved and what will be done to engage potential beneficiaries?

Fundamental to the success of the research is a strong collaboration between the project partners and engagement with stakeholders to provide important results in the most useable form.

In the UK there is a significant amount of infrastructure located at or close to the coast, some of it highly vulnerable to relatively small wave events as well as extreme storm events. Most published overtopping studies, and hence guidance documents, are based on the prediction of average overtopping rates per hour. Whilst these are undoubtedly useful for estimating drainage requirements and making flood predictions if the drainage is inadequate or becomes blocked, they give little insight into the damage that may be caused by a single extreme overtopping or impulse event, which could cause global structural failure of sea defence works.

This project addresses the question of the extreme response, whether this is wave run-up, overtopping volume or impulse, in the context of the individual largest and most damaging waves within a long random sequence of severe waves - a storm event. Hence, this work may lead to important insights of great benefit to those who have responsibility for protection of coastlines (DEFRA, Environment Agency, Local Authorities with coastlines, English Nature, Water authorities, and engineering consultancies such as Halcrow and HR Wallingford). Results of this work would also be beneficial for the worldwide community of coastal engineers (both academic researchers and industrial practitioners) interested in the fundamentals of wave action.

Dissemination activities will include publication of the research findings in leading international journals, and participation by ENFORCE researchers in international conferences and UK meetings. Engagement with learned societies will occur through the Society of Underwater Technology via their SUTGEF group, currently chaired by the P-I Prof Taylor. This is an obvious route for regular informal presentations to civil engineering academics, graduate students, professional oceanographers, professional coastal engineers etc. We also envisage a one day mini-symposium at the end of this project to provide a launch-pad for our main results, to which DEFRA, the Environment Agency, Local Authorities with coastlines, English Nature, Water authorities, engineering consultancies, civil engineering academics etc. would be invited. This may be run under the auspices of the Marine Institute (http://www.plymouth.ac.uk/marine), which comprises 3,000 marine-related academic staff, researchers and students.

The experiments at Plymouth and computer-generated movies of the simulations will make excellent material for university open days etc. to engage the interest of visiting school groups - exciting the interest of the next generation of engineers.