Sections of a €550 million motorway being constructed in Co Galway may have to be raised in parts due to flooding, according to a leading hydrologist.

Prof Paul Johnston of Trinity College Dublin’s civil and environmental engineering department says he and colleagues had warned planners of the risks of running the Gort-Tuam motorway route through a “minefield” of turloughs, or disappearing lakes, in the karst limestone area.

The 57km corridor under construction was engulfed in several areas between Coole and Kiltartan during the recent storms, with water levels peaking late last week and only slowly receding when viewed by The Irish Times yesterday.

Micheál Burke, whose farm and stud are on the motorway route, says that the planners would not listen to local residents who had experienced serial flooding in the area since the mid-1990s.

“They have run in through a turlough on my land,” he says.

The four-lane motorway, being built under a public-private partnership, is designed to replace the existing N17/N18 routes.

Significant

When finished in 2018, the motorway will bypass Tuam, Ardrahan, Claregalway, Kilcolgan, Clarinbridge and Gort.

Prof Johnston, who was acting as a consultant to the National Parks and Wildlife Service during the planning stages, said that routes were narrowed down to four options between Gort and Athenry.

“We advised on a route slightly to the east of the current one, which would have necessitated building a small embankment, but which would have tried to avoid the sort of water levels it is experiencing now,” he said.

Boreholes were drilled to try and find conduits as part of the case, he recalled.

Died in cavern

Prof Johnston took a canoe to the area last Friday with botanist Dr Micheline Sheehy Skeffington and Dr Nick Scott, and noted the impact of water continuing to move towards the sea at Kinvara from the Slieve Aughty mountains.

The existing N18 is still impassable at Labane, north of Coole Park, where traffic has been diverted for many weeks, while Kiltartan church and Thoor Ballylee also remain flooded.

Build tunnel

However, the tunnel designed to be just over five metres (16ft) high was under almost four metres of water last week, he said, and is now under just over two metres of water.

”It’s not a tunnel if it is going to be underwater for four months of the year, and yet they kept telling us at the time that the 2009 floods were a one-in- a-100 years event,” Mr Burke said.

Transport Infrastructure Ireland, who are building the new route, said that a “detailed environmental assessment was carried out during the route selection process”, which “informed everyone involved in the process of the potential for flooding throughout the region”.

Climate change

The M17/M18 was still a “construction site” and was not due to open until 2018, he added.

He noted that the M6 Dublin-Galway motorway was opened early to facilitate access during the floods of 2009.