‘There’s a sense of desperation’ - protecting Dublin’s soft coastline from the erosion of tides and storms

Michael Moynihan has become unusually attuned to the rhythms of the tide and the warnings of storms.

Moynihan and his wife Bríd run the The Brook Pub, which sits near the shore in Portrane in north Co Dublin, just a few steps from the beach.

It wasn’t always that close.

A series of aerial photographs hanging in a corner of the bar show that just a few years ago, in 1998, the sea used to be separated from the pub and houses by a stretch of grass-covered dunes.

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‘The Beast from the East in 2018 was the one that really took the lumps – it was a high tide plus an east wind. We knew then that there was trouble ahead. Slowly but surely [the dunes were] being nipped away’

—  Michael Moynihan from Portrane, north Co Dublin

But in the last few years the combination of high tides and severe storms have swept away the sand in the dunes, bringing the sea closer to the pub and the houses along the shore.

“The Beast from the East in 2018 was the one that really took the lumps – it was a high tide plus an east wind,” he said.

“We knew then that there was trouble ahead. Slowly but surely [the dunes were] being nipped away.”

The Moynihans are lucky. The pub and their house, which is next door, sit behind a steel revetment that was built in the late 1950s, which has arrested the erosion to some extent.

But the sea has been encroaching steadily elsewhere on the shore.

A little further down the beach Paul Mulville, a Social Democrat councillor, has seen a sand bank in front of his house fall away after the recent Storm Kathleen, giving him a sea view he doesn’t particularly want.

The sea has already undercut one house nearby, causing it to fall on to the beach, while the erosion has seriously imperilled several others.

“There’s a sense of desperation in the area and hopelessness – there isn’t a sense of anything happening any time soon,” Mulville said.

“There’s no safety net for people if a house goes: that they might be rehoused or relocated or bought out or something like that. It doesn’t exist. That’s why people are so afraid of what might happen to them,” he said.

The problem of erosion in parts of Dublin seems to have grown more acute in the last few years. A recent assessment of shoreline change in Dublin by the Geological Survey Ireland between 2000 and 2021 showed that 19 per cent of the shoreline had experienced moderate erosion in that period, while 7 per cent had experienced high erosion. Portrane, Rush, Portmarnock and Donabate were identified as high erosion areas.

The problem seems to be accelerating. The same study found that in the latter half of that period, the years from 2013 to 2021, there was “a rise in rate and scale of erosion along soft coasts of Dublin”, both in terms of the speed of the erosion and the extent of the area affected.

The personal stories of the local residents seem to bear this out. Tom Barton, who lives a few doors down from The Brook, lost six metres of his garden during one storm.

“The visual impact is tremendous, as anyone who walks on the beach can see, but there’s also the mental torture that you’re going through every day knowing at some stage you’re going to lose your home,” he said.

Erosion can be tackled, but the solutions for Portrane are limited, according to Adrian Henchy, a Fianna Fáil councillor for the area, because it’s a special area of conservation. That means it’s not possible to throw in big heavy-engineering solutions such as more steel revetments or a rock wall, which would have a negative impact on the flora and fauna of the area.

The short-term plan has been to install along the beach a wall of giant, movable, hexagonal concrete pillars called seabees, each of which stands around four feet tall. The idea is to fit them together in a long, honeycomb style wall to break the waves before they reach the dunes. They work, according to the residents of Portrane, but only up to a point. Eventually they begin sinking into the sand, reducing their ability to slow the waves.

The longer term solution is to build a series of sea groynes, long arms of rock, rubble or concrete reaching out into the sea to break the waves and reduce their ability to pick up speed and ravage the beach and the dunes.

The view from the beach shows a 20-foot bank that appears to have been bitten away, exposing bare sections of soft, sandy soil, over which peek the tops of houses

The problem is that this solution takes time and needs to go through a number of regulatory hurdles, including approval from the newly formed Maritime Area Regulatory Authority (MARA).

All of which means, Henchy said, “that the process has been frustratingly slow”, with no certain timeline for the construction of the groynes.

The effects of the sea’s battering of the shore has been significant. A walk along the beach in Portrane gives a vivid illustration of the problem. Hundreds of metres of land along the shore have been undercut by storms and tides, bringing the beach and the shore closer to the houses.

The view from the beach shows a 20-foot bank that appears to have been bitten away, exposing bare sections of soft, sandy soil, over which peek the tops of houses.

At one point a huge section of garden decking has slipped down and sits lopsided on the beach. Further up the beach drains and cables are exposed. Elsewhere, a garden shed sits precariously over a rapidly eroding cliff edge.

Houses have already been lost, most notably one local house after damage caused by Storm Emma in 2018.Others are barely hanging on.

Portrane may be the most extreme example of coastal erosion, but it is by no means a problem limited to this part of Dublin’s coastline. Irish Rail has been working hard to buttress rail lines used by the Dart and mainline services, while Wexford has seen similarly high volumes of erosion in recent years.

Public understanding of the effects of erosion is imperfect, according to Dr Jimmy Murphy, a UCC academic specialising in coastal erosion, and can vary considerably depending on a range of factors. While some beaches such as Portrane are rapidly eroding, many others can be observed growing.

“Part of the problem in managing the Irish coastline is that we don’t have long-term data on beach processes and beach level variations, so it is difficult to determine the optimum solution for protecting a beach,” he said.

[ Sea-level rise and 'storminess' threaten Ireland's sandy beaches ]

The most common solution in Ireland is rock revetments – sloping structures – placed at the back of the beach, which arrest erosion. Such revetments are not always the ideal solution, however, since they don’t deal with the fundamental cause of erosion – what Murphy terms “sediment deficit”, or more simply a lack of sand.

That raises the issue of beach nourishment – essentially dredging sand from the sea bed and pumping it on to the beach to replace what has been lost.

‘At the moment we let nature decide where we protect – we let the damage occur first. That’s not good enough for people in houses at risk; we need a long-term plan’

—  Dr Jimmy Murphy, UCC academic specialising in coastal erosion

“You can restore seemingly impossible solutions if you put in enough sand and funding,” he said.

“There was one case in the US where a section of a barrier island, West Hampton Dunes, had been destroyed and was rebuilt through extensive beach nourishment.”

For Murphy, that’s the reactive approach, but Ireland would be better served by a proactive approach. He is working on a study of Cork’s coastline in order to develop a coastal vulnerability index to standardise how to select areas of coastline that will need protection.

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“We need to move to a more managed process in terms of dealing with coastal erosion rather than an ad hoc method,” he said. “At the moment we let nature decide where we protect – we let the damage occur first. That’s not good enough for people in houses at risk; we need a long-term plan.”

All of which may come too late for some of the residents, and their anxiety is only growing.

Tom Barton knows his home is one of the most vulnerable in the area and he is desperate for some interim measure to help protect the house while the groynes are going through the planning process. .

“The speed of build is a serious issue, so unfortunately emergency measures need to be introduced now,” he said.

“It would give me and a lot of us around here a bit of peace of mind.”

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