Dublin faces flood risk if Shannon water pipe is not built, says Uisce Éireann

The water utility company said it will seek planning permission for the scheme this time next year.

If approved, it will be one of the biggest infrastructure projects in the history of the State. More than €74m has already been spent on the plan.

Best-case scenarios would see the 172km pipeline completed in 2032, with costs estimated at between €4bn and €6bn.

However, Uisce Éireann asset strategy manager Angela Ryan said these costs could rise if the project is delayed, and stressed it is in the State's best interest to proceed with plans as quickly as possible.

"With inflation, the further you push out the start date of the project, the more expensive it becomes," she said. "Those higher ranges — where you're going up to €6bn and over — they're for if the project is delayed for 10 years before it starts."

With considerable delays and cost over-runs at the new National Children's Hospital and a lengthy lead-in time to the delivery of a metro project for Dublin, there is a lack of public confidence in the State's ability to deliver large public infrastructure projects.

Ryan said the pipeline should be different. The plan would see a water treatment facility built in Birdhill, Co Tipperary, similar in scale and function to the country's largest treatment facility at Ballymore Eustace, Co Kildare.

Water would then be piped through the midlands for use in Dublin and other towns near the route.

"It isn't the children's hospital," Ms Ryan said. "It's not redesigning the wheel. It's just a really long version of what we've done before. We'll probably split the pipeline contracts into four or five contracts, and keep them moving at the same time. So we think about 56 months or so is what we have in the schedule."

Planning delays are seen as a significant risk to the scheme. An unrelated wastewater project proposed for Dublin has been tied up by planning issues for six years, and Ms Ryan believes planning matters would be better dealt with by experts in this field, rather than litigated in the High Court.

"It's the wrong place to adjudicate any infrastructure project," she said. "We should allow the planners, as the competent planning authority, An Bord Pleanála, and the EPA [Environmental Protection Agency] as the environmental authority to adjudicate on the Shannon project. If that is the case, we should get the consents. We've done the work. We can prove we're not going to have a negative impact and we should be allowed to get on with it."

Another round of consultations will be held in November, and a compensation scheme for landowners is being worked on

Uisce Éireann has held consultations with landowners along the proposed route to try to generate support. Another round of consultations will be held in November, and a compensation scheme for landowners is being worked on.

This would result in them retaining their land above the pipeline, with Uisce Éireann able to gain access for works and maintenance via a right of access. Future development would be restricted at ground level above the pipe.

Uisce Éireann said €74.2m has been spent bringing forward the pipeline plans since 2014, with extensive studies, analysis and reports completed in order to get approval in principle from the Government last June. This included creating an initial design and four rounds of public consultation to prepare for a planning application.

Government funding has not yet been committed, but the Cabinet is working off a €6bn estimate. A report by UK-based consultants HR Wallingford has warned the cost could rise to €10.4bn in a worst-case scenario.

Ms Ryan said the current estimates include contingency costs, some of which may not be needed if the project runs smoothly and without delays.

She believes the project should be considered worthy of investment from the €14bn Apple windfall.

"Housing targets, foreign direct investment — all of that is dependent on water and wastewater capacity, so I'd regard it as an excellent investment for any windfall monies," she said.

Much of the controversy surrounding the plan stems from questions about the need for it. Two groups opposed to it, the River Shannon Protection Alliance (RSPA) and Stop The Pipe, say high leakage from Dublin's water infrastructure undermines the project.

Uisce Éireann said addressing leakage alone is not enough to guarantee water supplies in and around Dublin.

​About 85pc of water for the Dublin region comes from the Liffey, and Ms Ryan said it is unsustainable to continue supplying 1.75 million people from one source — this second source is needed to mitigate against supply risks and "huge vulnerabilities".

"If we had a major pollution incident and one of the treatment plants had to switch off for 24 hours or 36 hours, it would really mean rolling shuts across the region," she said.

"In Munich or Paris, if they had an issue at one of their sites, they'd switch to another treatment plant — and nobody in the system would notice. Because we don't have that capacity, everything essentially becomes a major incident with huge knock-on implications."

The pressure of demand without a second source could expose Dublin to future flood risks.

"We will probably have to ask the ESB to temporarily store more water at Poulaphouca in winter for the next number of years to allow us to produce more at Ballymore Eustace," Ms Ryan said. "That is very problematic for the ESB because their storage profiles are based on dam safety and flooding. However, we're going to have to have a look at a risk-sharing model with the ESB.

"That risk is increased flood potential along the River Liffey, because if you're storing more water in winter, that's when you can get the storms up here at Poulaphouca — and it potentially increases flood risk."

It would not be prudent, in the interests of the country, to commit this major resource on the basis of an inadequate proposal

The ESB controls the flow at dams, but hydroelectricity accounts for just 2.3pc of Ireland's electricity generation, so dam safety is the priority at reservoirs.

Yet cases can arise during very wet periods when water has to be discharged from dams when river levels are high downstream. This heightens flood risks.

Ms Ryan said increasing this risk is not sustainable over the long term.

The River Shannon Protection Alliance (RSPA) argues that not enough thought has been given to alternative plans. It wants to see an independently designed alternative, using the existing water sources available in Dublin, to be put forward and examined.

RSPA spokeswoman Kay Mullane said: "Uisce Éireann has no Plan B in relation to the Shannon pipeline project. We have given extensive consideration to alternative sources of water in the Dublin area and are confident there are many solutions that are not unjustifiably expensive or environmentally unsustainable.

"It would not be prudent, in the interests of the country as a whole, to commit this major resource on the basis of an inadequate proposal."

Ms Ryan said alternatives are not feas­ible, pointing to the vital role that dams play in enabling significant amounts of water to be extracted from rivers without causing environmental concerns. Ireland has only four suitable dammed rivers: the Shannon, the Liffey, the Lee and the Erne.

The Lee has been earmarked for a new project, piping water to west Cork, so the Shannon is best placed to solve supply issues in Dublin and the midlands.

"When you're taking water supply from a river, the difference in volume you can take if there is and if there isn't a dam is enormous," Ms Ryan said.

"The Plan B, ultimately, if it ever did come to it, would probably be trying to build some form of desalination scheme, but there would be probably a 20-year lead into that. It would be so expensive, and not a single other area of the country would benefit from it.

"Whereas the proposal to treat water down in Tipperary puts the second biggest water treatment plant at the other side of the country, which means anywhere along that route can get access to treated drinking water."