Eco-engineered seawall built for the protection of marine life

Swansea University researchers have led the Mumbles Sea Hive project, with the aim to include features in the seawall that will enhance biodiversity.

Sections of the wall are being made from concrete panels with ridges and patterns that mimic the rough contours of a rocky coast, to provide gaps and crevices where sea creatures can live.

Dr Ruth Callaway, a bioscientist at Swansea University and head of Blue Cube Marine Limited, led the research to test out which type of panel and location would work best in attracting marine species.  

The researchers placed 135 concrete test panels – hexagonal in shape - on the sea wall in Mumbles, before the building work got under way.

Each panel was cast with one of 13 different surface textures. The idea was to compare the different designs to see which would do best in attracting marine species.

The panels were erected at three different sites on the sea wall 50m apart, with some more exposed to the waves than others. At each site, panels were fixed in three rows at different heights, to assess any differences according to how long they were submerged under water.

After a year, the researchers analysed the different panels and locations, and found that the panels with a surface of pronounced ridges and a rough structure were best for attracting marine life; the most common species that colonised the panels were two types of barnacles, which are also common along the rocky coasts of the area; and that no species colonised the panels that were most exposed to waves.

The researchers said they chose the panel design that was amongst the best performers in attracting marine life. In addition, the final design incorporated hexagonal grooves to provide additional shelter for marine species, in line with the research findings.

In a statement, Dr Callaway said: “It’s great to see this research translated into a major real-life engineering project that will enhance our local environment for generations to come.

“The Mumbles seawall is one of the first major engineering projects in the UK to incorporate this kind of research. The way in which the project was planned and delivered, with all partners involved – from designers to concrete manufacturers - was vital to its success. We hope this will inspire similar projects.”

The research team said that the panels are now being cast in concrete on site, and that the prom itself will feature lots of new soft landscaping with the aim to provide ecological enhancement.

The Mumbles Sea Hive project involved close collaboration with Swansea Council, which is managing the works and largely funded by the Welsh Government, alongside the construction company Knights Brown, who were the business partner in this EU funded research project.

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