Eoghan Murphy
Question:235. Deputy Eoghan Murphy asked the Minister for Public Expenditure and Reform if he has investigated the need for tidal defences in the River Liffey including the possibility of a retractable barrier. [9449/21]
View answerWednesday, 24 February 2021
Questions (235)
Written answers
In relation to assessment of options for tidal defences in the River Liffey, including the possibility of a retractable barrier, I am advised that the Eastern CFRAM for the Liffey River Basin (referred to as Unit of Management ‘9’) assessed a range of flood risk management options for the Liffey Catchment and Dublin City.
As part of the assessment of options for managing the overall flood risk in the Liffey sub-catchment, the option of a tidal barrier in Dublin Bay was considered, but was rejected from the screening process on grounds of economic viability. Details of the respective options’ assessment process can be found in the Preliminary Options Report for UoM09 at floodinfo.ie/publications/
No further tidal options were assessed for River Liffey in the Dublin City AFA in the Eastern CFRAM Study due the presence of proposed/ongoing schemes at the time of the Study (as below), and the limited risk predicted by the modelling under the existing scenario in the areas not covered by the proposed/ongoing schemes i.e. along the Quays.
Prior to this, a pre-feasibility level of assessment of a tidal barrage for Dublin was carried out as part of the Dublin City Council’s 'Project 2030 - Integrated Water Resource Management Planning for the Dublin City/Dublin Coastal Region' (Pre-Feasibility Study, June 2009). Dublin City Council was the Client for this project. While this project examined a range of combinations of river and marine hydraulic events and demonstrated that the construction of a system of barrages could be a viable flood prevention strategy for Dublin, it also recommended that many detailed studies to address other issues would be necessary if the project progresses.
In the meantime, works on the South Campshires Flood Protection Project are substantially complete, with the OPW’s direct labour crew now finished on site. While Dublin City Council are currently addressing some final elements of the project, flood protection is currently provided. €6.3 million has been spent on this project to date.
The Spencer Dock Flood Relief Scheme is also complete, having been initiated in 2006 following major flooding in 2000, and constructed from 2007 to 2009. The scheme, which comprises the restoration of a sea lock, provides protection against a 100-Year flood (1% Annual Exceedance Probability) for 1,200 properties against flooding from the River Liffey.
The management of potential increases in future flood risk due to climate change will also be assessed under actions set out in the Climate change Sectoral Adaptation Plan for Flood Risk Management (OPW, 2019). These will include examining past schemes for adaptation requirements, and the ongoing examination of potential future flood risk in areas currently not prone to flooding, and of options for managing and mitigating this risk.