WireWall – a new approach to measuring coastal wave hazard

In the UK £150bn of assets and 4 million people are at risk from coastal flooding, whilst the construction of sea wall defence schemes typically cost at least £10,000 per linear meter. With reductions in public funding, rising sea level, changing storm conditions and 3200 km of coastal defences (i.e. about £3bn), cost savings are required that do not cause a reduction in flood resistance. The design of new coastal flood defences and the setting of tolerable hazard thresholds requires site-specific information of wave overtopping during storms of varying severity. By converting an existing wave measurement technology into a prototype overtopping monitoring system "WireWall", field observations of the wave-by-wave horizontal overtopping speeds and volumes were made at our case study site Crosby, in the North West of England. The new data quantify the wave overtopping conditions observed, which varied with the wind, waves and tide, allowing better understanding of how wave hazard at Crosby changes with the local conditions.