Scottish storm wave study to protect coastal areas

Britain's coastal defences could be helped to withstand powerful storms triggered by climate change, a study of wave dynamics by a Scottish university shows.

Storms hitting the Ayrshire coast. PICTURE: JEFF MITCHELL/GETTY IMAGES

In the first study of its kind, researchers at the University of Edinburgh developed a model showing how the millions of tonnes of water inside large waves collide with cliffs, seawalls and buildings.

Improving sea walls could help limit loss of life and damage to property as coastal waters become stormier over coming years, say the findings, published in the Royal Society journal Proceedings A.

Their findings could help engineers design coastal defences better able to stop sea water spilling over on to land – known as overtopping.

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.

Scientists at the universities of Edinburgh and Hokkaido in Japan recreated stormy sea conditions in a 24m wave flume in Japan, gauging the impact of waves on vertical walls.

A scaled-down version of a seawall was bombarded with waves, tracked using a high-resolution video camera.

They found water is dispersed in a distinct pattern that varies depending on the size of waves. The pattern differs from those produced by other types of spray, such as those produced by industrial sprayers used in car and agriculture industries.

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 defence strategies which have until now not taken into account the pattern of spray produced by waves, the team says.

Professor David Ingram, of the University of Edinburgh’s school of engineering, said: “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.”

The UK has been hit by a number of storms in recent years including Storms Eva, Frank and Desmond