Coastal resilienceImproving seawalls to strengthen coastal defenses
Britain’s coastal defenses could be designed to better withstand storms triggered by climate change. Improving seawalls could help limit loss of life and damage to property as coastal waters become stormier over coming years. New research will help engineers design coastal defenses that are better able to stop sea water spilling over on to land — known as overtopping.
Britain’s coastal defenses could be designed to better withstand storms triggered by climate change, a study suggests.
Improving seawalls could help limit loss of life and damage to property as coastal waters become stormier over coming years, the study’s authors say.
The researchers have developed a way of predicting what happens to the millions of tons of water inside big waves when they collide with cliffs, seawalls, and buildings. Their findings could help engineers design coastal defenses that are better able to stop sea water spilling over on to land — known as overtopping.
Stormy seas
When a breaking wave collides with an upright structure, a powerful jet of water is thrown straight up into the air. Researchers found these huge sheets of water then split into several “fingers” before breaking apart into a spray of droplets, which can hit people and property with real force. Saltwater can also cause damage to buildings, vehicles, and transport infrastructure.
U Edinburgh says that scientists at the University of Edinburgh and Hokkaido University recreated stormy sea conditions in a 24m wave flume in Japan to gauge the impact of waves on vertical walls.
A scaled-down version of a seawall was bombarded with waves, which researchers tracked using a high-resolution video camera. They found that water is dispersed in a distinct pattern that varies depending on the size of waves.
Coastal defenses
Based on their findings, researchers developed a statistical model to calculate the pattern of spray produced by wave impacts. This could help inform future sea defense strategies which have until now not taken into account the pattern of spray produced by waves, the team says.
The study is published in the Royal Society journal Proceedings A. The research was funded by the Japan Society for the Promotion of Science.
Professor David Ingram of the School of Engineering says: “The UK and Japan are island nations on the edge of large oceans where storms can create very big waves. With climate change increasing the intensity and frequency of storms, a better understanding of the interaction of waves and our natural and engineered coast is critical.”
— Read more in Y. Watanabe and D. M. Ingram, “Size distributions of sprays produced by violent wave impacts on vertical sea walls,” Royal Society journal Proceedings A 472, no. 2194(12 October 2016) (DOI: 10.1098/rspa.2016.0423)
