Why coastal areas are more vulnerable 

Ireland has over 7,500km of coastline, making the country more vulnerable to coastal flooding, with many areas such as Dublin, Cork and Galway in coastal flood risk zones. High tides, storm surges and rising sea levels are increasing the risk, particularly if a high spring tide coincides with a deep storm system. This event can create surges which overwhelm sea defences, resulting in flooding in low-lying coastal regions. 

Climate change is significantly raising the risk of flooding even further. The Irish Times reported that sea levels are 11cm higher than they were 30 years ago and are continuing to rise. This largely due to the thermal expansion of the oceans and the melting of glaciers and ice sheets, compounded by ongoing changes in land levels.

Another major concern is erosion. Waves naturally affect the coastline, gradually wearing them away. Intense storms accelerate the rate of erosion, especially in areas with softer geological formations. That means that the natural barriers that protect the land are slowly fading away.  

Erosion can also happen because of human activity, particularly through construction. Modifying the landscape and removing natural vegetation can reduce the region’s ability to absorb excess water, leaving it more vulnerable to flooding.

Which infrastructure is most at risk? 

While much of Ireland's national road network is inland, some coastal routes are exposed to flooding risk. The N69 between Tarbert and Foynes is identified as one of the most exposed sections, lying along the Shannon estuary and vulnerable to sea level rise and storm surge. Smaller, less-used roads in towns and villages are more at risk as they are often less protected by flood defences and may have had less investment in resilience measures. 

Other important infrastructure such as Dublin Port, the Jack Lynch tunnel in Cork and the Limerick tunnel under the River Shannon have also been flagged as areas of concern. 

It’s not just roads and tunnels that are under threat. Public infrastructure such as pathways and lamp posts is also at risk, potentially leading to safety hazards and significant costs to local authorities. Meath Council is seeing this problem first hand along the Laytown–Bettystown shoreline, where coastal erosion is visibly undermining a public pathway and creating safety risks for pedestrians. This places the burden of repair and replacement on already stretched local authority budgets. If left unaddressed, similar issues could escalate into more significant structural failures, requiring more expensive intervention works.  

Early warning signs to watch for 

Climate change is an ongoing process, but there are some early signs that can be monitored. Frequently flooded roads, overwhelmed drainage systems or coastal defences that require constant repair all indicate increasing pressure from the sea. 

It’s important to watch for physical changes to the coastal landscape too. Eroding cliff faces and disappearing beaches for example, could be indicators that the natural ecosystems are under increasing stress. 

What preventative measures can be taken?  

The key to reducing the risk of coastal flooding is to ensure effective barriers are in place and the ground is strengthened. In addition to improving the natural barriers of the coastline through sand dune regeneration or salt marsh restoration, geotechnical methods can also help improve ground conditions. 

Traditional ground remediation methods such as underpinning or piling can be effective solutions; however, they can be slow, disruptive and costly. Implementing these works may be impractical on busy roads or operational infrastructure. 

Mainmark’s Teretek® resin injection is one method that offers a faster, less disruptive solution. This technology involves injecting the resin into voids beneath the ground through small holes, without the need for heavy machinery. Some of the key benefits include: 

• Filling voids to improve the ground's load-bearing capacity.

• Densifying soils to icnrease ground strength.

• Re-levelling surfaces - the process can gently lift and re-level road surfaces, slabs, pavements, providing even support for vehicles equipment etc.

This non-invasive method keeps downtime and costs to a minimum. 

Understanding the risks of coastal flooding is essential when it comes to protecting Ireland’s infrastructure. With climate change increasing the strain on coastlines, asset owners need to focus on strengthening ground conditions beneath road networks, public pathways and vital coastal infrastructure such as ports to improve efficiency and safety.  

Ireland's coastline is under increasing pressure, and the infrastructure built along it is only as resilient as the ground beneath it. With this increasing strain, now is the time for asset owners and local authorities to act, before damage becomes visible. Early assessment of ground conditions can make a significant difference to the cost, disruption and long-term integrity of coastal infrastructure.  

If you would like to discuss your ground conditions or coastal infrastructure concerns in more detail, get in touch with the Mainmark team today.