Dodder 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