Water chiefs are facing calls to tap into a massive hidden network of underground rivers off the west coast in a bid to solve worsening droughts on the Aran Islands.
Geologists are urging Irish Water to run new electric and sound wave surveys to track the systems – some as long as 48 kilometres and 20 metres wide – which flow out north of Clare under the seabed.
Researchers believe these natural pipelines are buried deep below the surface limestone and could hold a potentially viable and treatable supply for islanders in Galway Bay.
Tiernan Henry, of the Earth And Ocean Sciences in NUI Galway, called on Irish Water to use technology to map potential well hotspots and allow exploration experts to drill for a permanent fix on the two worst affected islands.
“From a geology and ground water perspective there’s no reason that these pipes and conduits for underground rivers that underpin the geology of Clare do not continue right out as far as the islands,” he said.
“We need to go out and prove it. We need to get into the ground prove it. We need the evidence that shows these things exist.
“I’d be surprised if they didn’t.”
Since this summer’s drought on the Aran Islands 27 tankers carrying 120,000 litres of water at a time have been sent to Inis Meain and Inis Oirr at a cost of €120,000.
Drilling experts estimate a successful well drilling operation – about €10,000 for a test bore – would ultimately cost less even if a series of trial holes were needed.
Irish Water said it was open to examining all possibilities to solve the supply crisis which frequently threatens the valuable tourist season on the islands.
The utility company refused to commit to drilling and said research carried out by hydrogeologists in 2010 reported that it was unlikely that ground water sources exist beneath the islands.
It offered to contact NUIG to explore the options of drilling for water in the seabed.
Inis Oirr Co-Op manager Paddy Crowe has claimed about 40% of what is being delivered into the island system on tankers is being lost and not coming out the taps.
About 20% of Ireland’s public water supplies are sourced from the ground with an increasing number of commercial operations like hotels sinking wells to cut costs.
In Laois 100% of public supplies come from groundwater, the Geological Survey of Ireland (GSI) said.
Mr Henry, an expert in hydrogeology, researched the existence of freshwater flowing out from the limestone landscape of north Clare and south Galway in underground channels.
“It is the same process that created the distinctive karst landscape of the Burren,” he said.
Mr Henry said it would be a surprise if the underground systems cannot be tapped into beneath the islands.
Local fishermen have long reported seeps or hotspots of freshwater pumping up from the seabed in Galway Bay.
Mr Henry said it may go some way to explaining why one deep well on Inis Meain has more reliable supplies of fresh water.
“The underground water is moving in very, very distinct zones,” he said.
“In the bay there are submarine ground water discharges or rises. We have identified a number of these. Most fishermen know where they are. They work that coast. They’ve known of them for years.”
Mr Henry added: “There’s no geological reason this should stop when you hit the coast. The coast is not where it was 10,000 or 50,000 years or one million years ago. We think of the islands as being out in the ocean. The smallest island is not that far out.”