Dublin City Council is to examine the possibility of building three giant barriers in Dublin Bay to protect the city from flooding due to global warming.
City engineers have begun an initial study into the feasibility of the tidal barrages as a long-term option to protect the city against rising sea levels predicted due to climate change.
The council will look at the prospect of three separate barrages to protect the city in an initiative known as Project 2030. These will include one close to the North Bull Wall and South Wall at the entrance to Dublin Port.
A further barrier between Sutton and Bull Island in north Dublin, and a third north of Howth Head, will also be examined.
Dublin deputy city engineer Tom Leahy told The Irish Times that such barriers would not be needed in the short term, but they could be necessary from 2030 on.
"We are looking at the moment at the long-term rise in sea levels that are going to occur and how we can address it," he said. "Climate change is happening but we have the time to identify the problem and to deal with it."
He said the council had also identified €100 million of flood protection works to be carried out over the coming decade to provide protection in the medium term.
Tens of millions of euro will also be spent on improving drainage works in the city, in the face of predicted rainfall changes which will put the city at greater risk of flash flooding.
The work follows the identification of Dublin as one of the areas in the country most at risk of flooding from climate change.
In a 2003 report for the Environmental Protection Agency by climatologists at NUI Maynooth, significant parts of the city close to the coast and also near the river Liffey were identified as being at serious risk from a sea level rise of less than half a metre.
Mr Leahy said the barrage study would look at highly advanced barriers which would be raised into place by hydraulic mechanisms when floods threatened.
A more permanent, immovable barrier at the entrance to Dublin Port, which could be built on and could create an entire new quarter for the city, will also be examined.
Dublin is the latest coastal city to investigate tidal barrages as a protective measure.
London has had a flood barrier across the Thames since 1984. Singapore is currently constructing a tidal barrage, while the city of Venice is developing an ambitious hydraulic tidal barrage.