Council Plans to Add “Rainscapes” in Five Places in the City to Sop up Heavy Rainfall

Dublin City Council plans to add “rainscapes” in five places in the city to sop up heavy rainfall, said John Stack, a senior executive engineer for the council’s Protection of Water Bodies Office on Monday.

It’s a pilot to test out nature-based solutions – things like wet ground, tree pits, and porous surfaces – to tackle flooding around sewer pipes flowing into the Santry River and the Dodder River, and around Montpelier Hill in Stoneybatter.

It’s also to make the areas around rivers look more pleasing, and allow children to play and people to walk around them, said Stack, at Monday’s meeting of the council’s South East Area Committee.

The “rainscape” would temporarily hold rainwater during times of heavy rainfall and urban runoff,  he said.

With climate change, the city is at greater risk of floods, and set to see a growing number of days of heavy rainfall each year, says the city council’s Climate Action Plan.

Five Trials

The council is planning a pilot on five sites in the city, said Stack. One stretch is on Montpelier Hill in Stoneybatter, as part of the greening strategy in the neighbourhood.

Two sites are along the River Santry.

In the South East Area, the council would retrofit its pilot design along the River Dodder at two locations: one along Milltown Road, and one along Eglinton Road.

At Milltown Road, between Churchtown Road Lower and the Nine Arches Bridge, there is a stormwater sewer, which discharges into the Dodder.

There, the council plans rain gardens to sop up water from the road’s gulleys. And, a swale, or a wet stretch of land, to store water during heavy rain.

“And then it would discharge to the river naturally, without a use of yet another pipe,” said Stack. They’ll also add footbridges, informal play spaces, and places for people to gather, he said.

“Most of the time this would be dry, it’s only during periods of excessive rainfall that it might store water for a temporary period,” he says.

Another sewer pipe runs underneath Eglinton Road and Brookvale Road and discharges to the Dodder at the bridge joining with Beech Hill Avenue.

Along Eglinton Road, car parking spaces and cycle tracks would be repaved with porous surfacing to soak up water.

What Next?

The council plans to go out to public consultation soon in 2023, and to start what’s called the “Part VIII process” for getting planning permission for its own projects.

The pilot should be built within a year, he said. Then, the council will monitor how it goes for a year, he said.

No entrances to residents’ homes should be interfered with during construction, said Stack. “We’ve endeavoured to make it a win for everybody.”

James Geoghegan, a Fine Gael councillor, said the project looks clever and innovative.

He asked if the cycle lane along Eglinton Road could be segregated while they are being repaved, given that the council’s active travel team is rolling out a segregated cycle network across Dublin in stages.

“The existing cycle route […] is sort of, the old school paint on the ground, with a white line just demarcating that there is a cycle lane,” said Geoghegan.

“It seems like a bit of lost opportunity, if construction works are to be carried out anyway, because that is, particularly Eglinton Road is a busy school route,” he said.

Stack says they are just upgrading the surface of the cycle path.

Carolyn Moore, a Green Party councillor, asked whether the council plans to address flooding at the source of the Dodder.

“Where we could be using, you know, huge swathes of land in the Dublin mountains to actually act like a bit of a sponge and soak up a lot of the water before it becomes a problem down in the city,” says Moore.

“The vision is yes,” says Stack. The development plan heavily pushes nature-based solutions, he says. “But we need to have some numbers on that before we progress to increasing the scale.”

Nature-based solutions differ based on the scale of the intervention, he says. There’s the small local changes right up to integrated catchment management, he said.

Those larger projects are different. “Where you’re looking at the entire river, how it functions, how you manage and reimagine the landscape and the watershed to store water and prevent it getting downstream,” said Stack.