What Lies Beneath – Why Dundrum Town Centre Flooded

Steve digs out his photos of the construction of South Dublin’s fashionable (and flooded) mall, and remembers what it was they built on top of . .

The dramatic scenes of water bursting into the upmarket Dundrum Town Centre mall were some of the defining images of the Dublin floods of October 2011, and the front page picture from todays Irish Times shows how badly the centre has been affected. Since its opening six years ago it has been my favourite of the Dublin suburban shopping centres, but its devastation by floods does not surprise me as a local with intimate knowledge of the grography that it replaced.

It could be, in fact, a perfect example of of the boom years building frenzy taken to its logical consequences, as the building of hundreds of apartments close by in the following years helped seal its fate.

The village of Dundrum has always perched on a slope at the bottom end of a narrow valley, with a good-sized stream (or small river) running through it. Various complexes lined the high ground on one side of the valley – the old PYE Television factory, later industrial estate, the 1970s original Dundrum Shopping Centre, and the old H Williams store at the southern end (which became Super Crazy Prices, and then Tesco). But the bottom of the valley and the river was always left pretty much wild, and I used to roam along its length in my childhood years, fancying myself as a fearless explorer as I waded upstream and forced my way through undergrowth.

In more recent years, as I made my way to work on a sluggish 48A in 2000 and 2001, the glimpse of the stream surrounded by green land as we crossed over the valley on the Ballinteer Road bridge just before the crossroads always gave a little glimpse of forgotten rural idyll. Until the day the bulldozers moved in, and they started building.

Dundrum bypass and Dundrum Town Centre under construction

Here is a shot I took sometime during 2001 or 2002 which shows both Dundrum Town Centre and the Dundrum Bypass under construction.  The picture is taken from a temporary pedestrian bridge over the valley errected during the period when Ballinteer Road was closed to traffic as a new, wider road bridge was built complete with car-park ramp downwards into the centre.

On the left is where Dundrum Town Centre now stands, and you can see the spot where the underground car-parks and delivery section join the bypass.

The valley floor has been leveled, and the stream boxed in, ready to be buried underneath the new development in a culvert.

When this photo was taken, it had been dry for a good period, and the stream was low, however it often ran much higher in wet periods. Nevertheless, the culvert once roofed would seem more than proof against even a four or fivefold increase in flow during very rainy periods.

However, in the years following the completion of the centre, hundreds if not thousands of apartments in dozens of new developments were built upstream, with much of the run-off from all these acres of new concrete flowing into the stream or the local drainage system. The huge flow of water from the Ticknock Hill development alone can be seen during wet periods cascading down a series of steps beside the M50 junction, and into the watercourse of this stream. Plus, all of the green land that lay undisturbed in this little valley is now built over, no longer able to absorb rainfall and run-off.

In the exceptional rainfall of the last 24 hours, when a months rain fell in a day, once the culvert was at full capacity, where else could the water go?

I’m not saying the planners failed here, this is an exceptional event, but perhaps, when we have building booms in future, we should be looking at things like runoff in the context of what else will be built in the area later, and planning for “once in 80 year” events.

Yes it will cost. But as much as the damage that now needs to be made good?

Steve