How local authorities help protect Ireland's coasts from erosion
Ireland’s coastline is always changing. Waves, tides and storms reshape the shoreline, wearing away the coast over time. This process is called coastal erosion, and it has been shaping the coast for thousands of years.
Most of the time, coastal erosion happens gradually. It becomes a concern when it begins to affect roads, railways, public amenities, natural habitats or other assets that communities rely on. As climate change increases pressures on some parts of the coast, local authorities are carrying out projects to manage these risks and protect vulnerable areas.
When coastal erosion becomes a problem
Climate change is expected to increase coastal risks in many areas. Even small increases in sea level can allow waves to reach further inland and attack parts of the coastline more frequently.
According to Mark Freeman, an engineer with Dún Laoghaire-Rathdown County Council, sea levels along the coast have risen by around 25 to 30 millimetres since the start of this century.
“This might not sound like a lot,” he says, “but it moves the high-tide line further inland. This creates a lot more pressure on coastal defenses.”
The effects are not always obvious at first. A small amount of erosion at the base of a cliff can eventually lead to larger sections above it collapsing. Over time, this can threaten nearby infrastructure and public spaces.
A project undertaken by Dún Laoghaire-Rathdown County Council close to Woodbrook Golf Club in the south of the county shows how coastal erosion can create challenges for communities. The site was originally a wetland area but was used as an unauthorised dump in the 1950s and 1960s. Although dumping was stopped in 1965, large quantities of waste remained buried there.
Over time, erosion removed the material protecting the old dump. As waves reached the buried waste, debris began appearing on the shoreline nearby, and it became an issue of local concern. The council carried out significant coastal protection works in response.
How coastal protection works are carried out
Before any work begins, engineers need to understand what is happening at a site and what risks are involved. This typically involves surveys, investigations and detailed design work. The information gathered helps engineers understand how the coastline is changing and identify the most appropriate response. Different locations may require different solutions depending on local conditions.
Public consultation is a key part of the process, enabling the community to provide input on the proposals and ensure it meets their needs.
At the Woodbrook site, the preferred solution was a rock revetment. A revetment is a sloping structure that runs along the shoreline, designed to absorb the energy of incoming waves and reduce further erosion.
Once the design was finalised, construction work began. The existing cliff was excavated and reshaped. A geotextile layer was installed to stabilise the base. Large boulders, some weighing around four tonnes, were carefully placed on top. This created a structure capable of withstanding wave action and keeping the shoreline intact.
Projects such as these are designed not only to address current problems but also to take account of future conditions. Climate change and rising sea levels are now important considerations in the design process.
Protecting assets that matter to communities
Local authorities carry out coastal protection works where important community assets are at risk. Mary Cahill, Senior Engineer with Wicklow County Council, points to work on the revetment at Arklow as an example.
“Amenities such as a caravan park and a running track were at risk from coastal erosion,” she says. “These can now be protected due to this work.”
Wicklow County Council has also carried out work to maintain the revetment along the Murrough wetlands north of Wicklow Town, helping to safeguard important natural habitats, as well as popular recreational amenities in the area.
A shared effort
Managing coastal erosion requires input from a range of organisations. Local authorities work alongside agencies such as the Office of Public Works, the Maritime Area Regulatory Authority and other stakeholders when planning and delivering projects. Environmental assessments, planning processes, and technical studies may all form part of the work.
“It’s a very collaborative process,” Cahill says.
This approach helps ensure that environmental impacts, community needs and long-term risks are considered before works proceed.
To learn more about how local authorities manage coastal erosion, see Coastal Change Management: A Practical Resource on the Climate Action Regional Offices’ website.