The River Shannon must be used to prevent a water shortage in Dublin, Uisce Eireann has warned.

The water utility is warning that treatment plants in Dublin are currently operating at “absolutely maximum output” – with no reserves in place to deal with potential shortages.

Speaking on The Pat Kenny Show, spokesperson Angela Ryan said the "preferred approach" to Dublin’s water issues is the controversial Shannon-to-Dublin water pipeline, which aims to divert about 2% of the river’s flow to the capital.

The €6 billion plan involves running a 170km pipe from the Parteen Basin in Tipperary to a reservoir at Peamount in Dublin.

People living along the proposed pipeline have objected to the plan – and The River Shannon Protection Alliance (RSPA) has warned that it would come with massive environmental and financial costs.

The group is calling on Uisce Éireann to address Dublin’s water shortages by fixing the leaks that litter its network of pipes in the capital.

View of city with river Shannon, Limerick, Ireland.

Ms Ryan said that the Greater Dublin area has about 9,500kms of water pipeline – three times more than Paris.

She said maintaining the pipeline is putting Uisce Éireann under major pressure and the utility is “really running out of options” other than the proposed pipeline.

She said the recommendation to use the Shannon was initially made in 1996.

“The predictions that were made during those early-stage reports are right,” she said. “The demand for water has increased over time.

“What we've done in that intervening period is we have reduced leakage significantly within the area, which has made space for more growth.

She said Uisce Eireann can currently put 600 million litres of water into its supply every day – less than the current demand for water in Dublin which is 611 million litres per day.

“There is absolutely no headroom and no redundancy within the system," she said.

River Shannon pipeline

Ms Ryan claimed the main problem is Uisce Eireann’s reliance on “a single source of water”.

“We take 80, 85% of the water we need for an entire region with nearly 1.8 million people from the River Liffey,” she said.

She said it might appear the Liffey has a lot to offer, but there’s only a certain amount usable by Uisce Eireann.

“The Liffey at the Quays is tidal,” she said. “So probably all of the water you're seeing is the seawater coming into the estuary there.

Heuston: “If you're to look at the low flow of the river or stand up at Heuston Station there at the bridge where the tide is going out and you’ll see how low the river actually is.”

The Ha'penny Bridge spans Dublin's River Liffey in June 2017. Picture by: Ben Ryan Photography / Alamy Stock Photo

Ms Ryan also said Uisce Eireann cannot extract water from the Irish Sea. 

“Uisce Eireann conducted a study and looked at over 100 options,” she said. 

“You can’t drink seawater so it has to go through a very extensive process to treat that water – the amount of blending we would require couldn’t really facilitate the supply for the city.” 

She said it would be easier to extract water from the Shannon than desalinate seawater from the Irish Sea.

The river Shannon passing through Athlone. Image: The Irish Image Collection

RSPA member Donal Whelan previously told Newstalk the Shannon pipeline would run through 500 farms, taking 50 metres of land while it’s being built and 25 metres after that. 

Fight the Pipe member Line Mineham is one of those 500 landowners, and he previously told Newstalk he would be a "fool" to give away 50 metres of his land for the pipeline.

Residents of Lough Derg are also concerned the pipeline would reduce popular amenities in the area, such as fishing.

“A lot of landowners think these compulsory purchase orders are inevitable, but I think this is engineering for engineering’s sake”.