BRIEFING NOTE – RIVER DODDER WORKS JANUARY 2012Posted January 27th, 2012
The 2004 Dublin Coastal Flood Risk Assessment Study (DCFRAS) identified the lower Dodder as one of several coastal locations at high risk of coastal flooding. A report to reduce flood risk from both tidal and fluvial on the tidal section of the Lower Dodder events was completed in January 2007 by Dublin City Council (DCC) with funding from the Office of Public Works (OPW). Following discussions with the Council, OPW agreed to undertake construction of the works directly with Dublin City Council project managing the project and the design. These works commenced in September 2007 at Ringsend Bridge moving upstream to Newbridge. The works have been undertaken on a phased basis by OPW. Works are currently ongoing between New Bridge and Lansdowne Railway Bridge. This will complete the final phase of the coastal risk reduction measures.
The following Programme, compiled by Dublin City Council, sets out the schematic timeframe of the current works and the possible timeframe for future works ( Note that the staffing of the city Council Flood defence team has reduced significantly since 2008 and may well reduce further post February 2012 which could compromise programme if not addressed).
Marian College & Lansdowne Road
Construction works are currently being carried out from Newbridge to Lansdowne Rail Bridge.
The key elements of these works are:
- Reconstruction of 60m of Quay wall damaged by flooding of October 2011.
- Construction of a reinforced concrete flood defence wall
- Masonry cladding to reinforced concrete wall
- Installation of flood gates
- Installation of railings to match previous phases of the Dodder Flood Defence Scheme
The works on the opposite bank on Lansdowne Road are currently at detailed design stage and are programmed to be constructed in 2012.
Dublin City Council has identified the following key elements as emergency works arising from the recent flooding in October 2011. Further discussion will be required between DCC and OPW in relation to the programming of the following list of works and possible inclusion under Minor Works Programme.
- River emergency maintenance and reconstruction of Licensed Vintners embankment Q1-Q2 2012.
- Construction of concrete wall upstream of Licensed Vintners, structural investigation March 2012.
- Reconstruction of flood wall at Sweepstakes development, DCC preparing Manager’s Order to have this classified as emergency works.
- Repairing river wall beside entrance to RDS at Anglesea Road
- Further emergency works have been identified and are scheduled to be completed in Q1 and Q2 2012.
Londonbridge / Newbridge – Bridge parapet raising
These works consist of raising the existing parapet walls to the design flood levels. They will require approval of Dublin City Council under Planning & Development Acts 2000-2006, Planning & Development Regulations 2001-2006 Part 8 procedures.
Phases upstream of tidal section covered by Dodder CFRAM Study
The Dodder Catchment-based Flood Risk Assessment Management (CFRAM) Study, currently being undertaken, has identified a number of flood defence measures required between the Lansdowne railway bridge and Donnybrook. These outline proposals contained in the CFRAMS require detailed design and further environmental assessment.
Arup consultancy services have commenced working for Dublin City Council to carry out all site investigation, environmental requirements, and draft planning permissions by September 2012 on works Phases from the railway bridge to Smurfit weirs which involve reconstruction or structural strengthening of existing flood defences and these may be considered as emergency works to align with adoption of Dodder CFRAMS by the three relevant councils.
The Environmental Impact Statement for these phases of flood defence works is programmed to be completed by Q.1 of 2013 and submitted to An Bord Pleanala. Construction timescales will be determined by An Bord Pleanala approvals at which stage more definite construction schedules can be advised.
Dublin Flood Initiative
The Dublin Flood Initiative, created by Dublin City after 2002 floods, manages risk from the main flood risks comprising:
- Coastal Flooding
- River Flooding
- Dam Failure
- Pluvial Flooding (Monster Rain which exceeds capacity of drainage system)
- Infrastructure failure
- Combinations of above.
The above Dodder works will address the Coastal and River flooding risk. Coastal flooding risk of the seafront at Sandymount was considered as part of S2S scheme and an assessment will be carried out in 2012 of the potential for local improvement works in advance of S2S project.
The Dams at Bohernabreena, on the upstream catchment of the River Dodder, were strengthened in 2004 to deal with calculated extreme events.
Pluvial modelling carried out as part of EU INTERREG Project Flood Resilient Cities is due for completion in Q2 2012. It will map the risk and identify guidance on flood resilience for new development and existing development including over 16,000 basements at high risk in the City. The River Dodder Catchment in the City is included in this study.
OPW anticipates its annual expenditure on the River Dodder to be between €1M and €2M over the next four years and has profiled accordingly.