CONSTRUCTION OF extensions in back gardens and paving front lawns for cars contributed to this week’s flooding of homes, Dublin City Council has said.
Defending its response to the unprecedented “monster rain”, the council said it took all measures within its power to protect the city from flooding and reacted promptly to last Monday’s downpour through the implementation of its emergency response plan.
However, the city’s drainage system was not designed to cope with the increasing urbanisation of Dublin, particularly the laying of concrete and tarmac over previously green spaces, the council’s executive manager Tom Leahy said.
“The biggest problems are not with the new developments, but with older housing estates built in the 1940s and 1950s. When they were built they had a nice green environment, with front and back gardens,” Mr Leahy said.
“It was never envisaged that people would concrete over their front gardens for cars or build extensions covering their back gardens. The drainage system was never designed for that.”
Front and back lawns provided natural drainage, but with the elimination of green space, the water had nowhere to go, he added. This resulted in many areas which were not close to rivers and were on high ground and normally free from flooding, being engulfed.
While there was ongoing work to replace the city’s largely Victorian drainage network, it was not feasible to expand the sewage system to cope with such intense rain. The solution was to retro-fit systems to try to replicate natural drainage, such as porous pavements and patios, and in public areas the development of “swales” – U-shaped grass margins which drain naturally and have the added benefit of capturing sewage-polluted water.
Labour TD Aodhán Ó Riordáin said he had some sympathy with the council, which was “struggling with the new reality of changing weather patterns”, but it was “very simplistic” to criticise home owners.
“Blaming extensions and driveways, when many flood alleviation schemes are incomplete, including in Donnycarney where an underground river has been identified and people can’t get insurance on their homes, is very simplistic.”
The city council, as the planning authority, had responsibility for granting permission for extensions and had responsibility for taking enforcement on any unauthorised work to houses, he said.
Mr Leahy stressed flood management measures already in place did prove effective. Flood-alleviation works completed three years ago on the Tolka prevented house flooding. The Dodder had also been “greatly improved” by flood alleviation works which were substantially complete.
