Dún Laoghaire Rathdown County Council received 500 calls during the aftermath of Storm Chandra , local councillors heard at the council’s monthly meeting.
Water services official Liam O’Dwyer told councillors the events of Storm Chandra were “unusual in a number of ways”. The rain fell from 1am to 6am, a rainfall warning was not issued for Dublin by Met Éireann and rainfall levels were up about 400 per cent of the norm over parts of Dublin for that week, he said.
He said from 1am to 7am, the rain gauge at Marlay Park measured 42 millimetres in six hours. By comparison, he said, 14mm was measured at Shankill.
There was an “extreme intensity to it,” said O’Dwyer.
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He said during Storm Chandra heavily saturated soils caused “overland flows more or a less immediately.”
He also said the watercourses were full, piped systems became surcharged and because of spring tides, some rivers could not discharge.
At Loreto Park in Rathfarnham, an area that was badly flooded, O’Dwyer recalled there being very little debris at the screen, which he described as “scary” because it meant the culvert was “full to capacity” and the water that was still coming “had nowhere to go.”
He added: “The intense rainfall fell at the upper regions of the watercourses. Had this event fallen from Sandyford to Stillorgan or Stillorgan to Blackrock, we would have been looking at a very different day because the systems in those locations would have been overwhelmed.”
In the post-event review or analysis, he suggested some methods that may have a positive impact in future such as examining the possibility of flood storage at Marlay Park and additional storage at Loreto Park, providing additional surface water pipe work on Slate Cabin Lane/Cullens Way and constructing some new surface water pipework on Enniskerry Road from Ballybetagh network to Brides Glen Stream.
He also recommended completing phase two of drainage works at Churchtown Avenue and exploring ways of improving communications to affected residents as the event unfolds.
Ten days later, he said they experienced “another challenge” when an orange rain warning was in place for Dublin.
He described it as an “unprecedented event” and said it “presented new challenges.”
The council’s chief executive, Frank Curran, said there was “exceptionally intense rainfall on saturated ground” during Storm Chandra.
He also praised the council teams who “went away, above and beyond the call of duty” as they were out from 5.30am on January 27th.
Councillors were also told that a full report is being prepared.
