[PR] Dodder flooding report

[Colm Moore]

http://www.irishrail.ie/cat_news.jsp?i=4590&p=116&n=237Dodder flooding report completed
04 May 2012

A study commissioned by Iarnród Éireann into the flooding of the Dodder in the vicinity of the Dodder Railway Bridge on 24th October 2011 has been completed.

There was torrential rain in the Greater Dublin area on the evening in question, with flooding occurring in many areas around the city.

In relation to the flooding at the Dodder Bridge, Iarnród Éireann commissioned the study to establish the factors leading to the flooding at the bridge, particularly as considerable scour damage to the bridge occurred during the flood event which led to the subsequent closure of the rail line for eleven days, and as there was local concern that scaffolding on the bridge for maintenance purposes may have exacerbated flooding in the area.

Fluvio R&D Limited, led by Professor Eamonn McKeogh, Professor of Hydrology at University College Cork, were commissioned to complete the study, which involved a hydrology study, a computer-based model and a laboratory-based physical model. Modelling included simulating the flooding which would have occurred and performance of the bridge with and without the scaffolding being present, amongst other modelling.

The study has found:
- The flooding in the area was caused by the high flood flow of the River Dodder
- The scaffolding and build-up of debris at the River Dodder Bridge did not exacerbate flooding in the area
- A build-up of debris would have occurred without the scaffolding being present due to the low soffit level of the bridge
- The scaffolding and debris led to greater scour damage in the vicinity of the bridge abutment, and the flow of water which this allowed actually served to reduce flood levels in the area

Click here to download a full copy of the Fluvio R&D report. (http://www.irishrail.ie/media/Dodder_Bridge_flood_report1.pdf)

[Colm Moore]

http://www.irishtimes.com/newspaper/ireland/2012/0505/1224315652740.htmlBridge works not at fault in flooding
KITTY HOLLAND

SCAFFOLDING ERECTED by Iarnród Éireann around a bridge over the river Dodder played no role in worsening heavy flooding in Dublin last October, a study commissioned by the rail company has found.

In fact it may have helped alleviate it, according to the report.

Record rainfall on October 24th last year caused flash-flooding costing tens of millions of euro in the capital.

Among the worst-affected areas were the Donnybrook, Ballsbridge and Irishtown areas. Such was the height of the river Dodder that the fire brigade had to be called to open a sluice gate, as a key could not be found for it.

There was damage at the bridge at Lansdowne Road, including erosion damage that led to the closure of the rail line for 11 days.

There was local speculation that scaffolding on the bridge at the time, which had been erected by Iarnród Éireann for maintenance work, might have exacerbated flooding.

The report published yesterday was carried out by Fluvio RD Ltd and led by professor of hydrology at University College Cork, Eamon McKeogh.

It finds the flooding in the area was caused by the high flood flow of the river Dodder, and by water pipes being overloaded

It says the scaffolding and build-up of debris at the bridge did not exacerbate flooding in the area.

A build-up of debris would have occurred without the scaffolding being present due to the low level of the bridge, the report adds.