Council looks at softer, nature-based ways to protect Fingal’s beaches and sand dunes

The Tuesday morning tide had pulled back from Burrow Beach and a small murmuration of starlings fluttered around the bright cloudless sky.

Either side of the beach’s entrance ran a length of rope fencing, there to stop people trampling on its sand dunes. Long marram grass grew among the dunes, binding them together.

But to the southern end of the beach in Sutton, two fence poles had fallen down, and inside the cordoned off area, which protects the dunes, there were numerous footprints in the sand.

The dunes, anchored by marram grasses, provide natural protection from coastal flooding and erosion, which is a growing problem along strips of Fingal’s coastline.

As such, they need protection from trampling, said Green Party Councillor David Healy at a recent meeting of Fingal County Council’s Marine and Coastal Management Strategic Policy Committee meeting.

“We need to be able to get people across the dunes, maybe with boardwalks, or just a few paths,” he said.

At the meeting on 21 September, Healy pointed not just to damage from trampling on Burrow Beach in Sutton, but also on Claremont Beach in Howth.

He asked for a report on how the council can use “nature-based solutions”, soft interventions to protect the county’s dunes and beaches.

Although the council has planted marram grass and put up rope fencing, it doesn’t yet have a strategy for how it plans to protect dune systems against worsening erosion, said Máire O’Brien of the Fingal Public Participation Network.

Fingal County Council senior park superintendent Kevin Halpenny, said the best way to protect dunes is simply to limit public access, which can cause damage.

In areas of Fingal badly affected by erosion, like Portrane and Rush, “nature-based solutions” might not always be appropriate because of the scale of the issue, Halpenny said. But it would be good to implement some in response to coastal change, he said.

Possible measures

At the meeting, councillors noted some of the measures, like fences and marram-grass planting, used along Fingal’s coastline to manage dunes and beaches – but also those that aren’t working or could damage them.

Healy had sought to bring forward a discussion around improving the council’s understanding of seaweed’s potential along the coastline, he said.

Seaweed supplies marram grass with many of its nutrients, Healy said.

Beach cleaning regimes tended to remove it in large quantities, which disrupts the natural process of assisting marram grass, he said. “One thing you can do is take it up from the coast and throw it up from the shoreline, towards the dunes.”

“But it does need to stay on the beach,” he said.

O’Brien of the Fingal Public Participation Network, said seaweed, like marram grass, helps dunes form. “When it comes to the base of the dunes, it actually collects sands and forms a next line of dunes outside the original.”

But around Portmarnock, she said, people have been complaining to the council about seaweed. “And it has been collected by the council.”

Moving seaweed to the right place could help with dune growth and stop people walking over dunes that are not covered in grass, she said. “Where there’s a very bare dune, if you place it at the base, then the dune is not attractive for people to slide down it, because they will end up in smelly seaweed.”

Another approach similar to O’Brien’s, Healy suggested, was to use old Christmas trees. “So typically, a Christmas tree is something to give a bit of structure and to help trap the sand.”

The beach committee in Portmarnock had done that in recent years, he said. “And they don’t really seem to have seemed to get the council co-operating with their proposals in that regard.”

Laying out seaweed, or indeed discarded Christmas trees, would be a cheap way to protect the dune systems, he said.

What kind of intervention?

O’Brien said that an overall strategy for Fingal’s dunes needs to be developed, which factors in climate change. “It’s noticeable that the strength of our storms is getting stronger,” she said.

“Of course, because they’re getting stronger, they’re activating more sand from the seabed, so there’s actually more sand in the system,” she said. “But they’re also impacting the dunes and the coastline in general.”

Dunes are a soft solution to flood prevention, storm-force winds and coastal erosion, she said.

In Portrane, there are concrete barriers, or “seabees” put in, but they are creating a hard coastline, she said. “What we need to do is to have a soft coastline.”

That means not putting in hard structures, like concrete blocks, posts, or rock armour, says Kevin Lynch, a geomorphologist at the National University of Ireland Galway. “It’s counterproductive.”

Lynch says that rock armour, for example, doesn’t protect sand dunes. “Really they protect what’s behind the sand dunes. Things that are of value to the humans, like houses and roads, and railway lines, and farm land.”

The first thing lost when authorities use rock armour is the local habitat, its plants and species, he says. “Because that’s usually built directly on top of the habitat.”

Reinforced concrete blocks were placed on Portrane Beach to try to stop erosion there in October 2018, says Social Democrats Councillor Paul Mulville. “They were emergency interim works.”

But what Portrane needs is a longer-term solution, he says.

Erosion at The Burrow in Portrane has been an ongoing issue since the 1990s, according to a coastal-erosion risk assessment, prepared by RPS Planning Consultants for Fingal County Council in July 2019.

That assessment said that a dune-management system – which meant reprofiling them, using batting and planting along with sand fencing – should be put in around the parts of Portrane’s dunes affected by significant erosion.

However, that system has not yet been implemented, and now Portrane’s grey, fixed dunes, which are located further away from the beach and can support larger shrubs, are entirely gone now, Mulville told the committee meeting.

It’s not too late, though, says Mulville.

The RPS consultants’ proposal of sea groynes – structures built perpendicular to the shoreline, for trapping sediments – sand replenishment and marram grass would hopefully restore the habitat that was lost, through a hybrid of engineering and nature-based solutions, Mulville says.

Best practice

Sand dunes are a more flexible and efficient way to protect the coast during storms than concrete blocks, Lynch says, as they absorb the energy of waves crashing against the shore.

“That’s why there’s certainly been a move towards whether we can utilise this nature-based solution for storm activity, to give us coastal protection,” he said.

Dune systems have dual benefits, he says, because they don’t only support the local habitat. “We also get things like that the water quality is better, as water filters through beaches coming from the landward side.”

Best practice at the moment is to look after and not remove seaweed that is on the upper beach, and to put up fences around dunes, he says.

The public needs to be more aware of this, said Lynch. “Visitors to beaches sometimes don’t appreciate what is being tried here.”

At the policy committee, Halpenny, the council’s senior park superintendent, said that the operations department responds to damage by the public to the dunes by limiting access.

“So the best protection for dunes is not to limit them, and not to have development that limits them,” he said.

In the likes of Portrane and Rush, solutions such as laying seaweed, might not be the appropriate response, due to the scale of the issues, he said.

“But certainly, that would be, in line with what’s in the development plan, the first port of call would be to try and have nature based solutions implemented in response to coastal change problems,” he said.

At the meeting, councillors agreed to revisit Healy’s motion in December.