South Campshires Flood Protection Project
The Dublin Coastal Flood Protection Report prepared for Dublin City Council in 2005 identified a number of locations where the current level of flood defences was well below that required for the future predicted sea levels. A number of these locations had existing levels of flood defence that were below even that required at current sea levels. Included in this latter category was a significant section of the South Quay wall extending from O’Connell Street to the Dodder. Much of the south campshire area was land reclaimed from the historic flood plain of the River Liffey. Thanks to support funding from OPW Dublin City Council have been working with DDDA to identify a flood protection strategy and a staged sequential improvement in technical defences.
DDDA had separately identified a requirement to enhance the south campshires between Millenium Bridge and Macken Street Bridge. It was agreed by DCC and the DDDA that this proposal should incorporate the flood defence levels required up to year 2030 (3.7m above Ordnance Datum).
The flood event of 2002 and subsequent events established that there is a relatively high risk of a further flood event exceeding the level of the quay wall at this location at any time (the current level of protection equates to a1/70 year event) even before climate change considerations are factored in. The results of any such inundation would lead to serious flooding over a wide area, due to the general topography of the area which slopes away from the river to a low spot.
The proposal is to erect a 900mm high concrete retaining quay wall faced with granite or brick 1.8m from the edge of the quay wall. The area between the quay edge and the new protective concrete retaining quay wall will be accessed by an access stairs at a number of locations.
The length of quays involved is some 1300 metres (say 1200 metres when existing buildings or raised walls are allowed for).
Clontarf Flood Defence
The Clontarf Flood Defence project comprises a series of flood bunds and walls along Clontarf Promenade between Alfie Byrne Road and the Bull Wall to protect nearby roads and properties from coastal flooding. The total length is circa 3km. Due to the synergies and common location of the North City Arterial Watermain and the Clontarf Flood Defences it was decided to combine these two projects.
Dollymount Promenade and Flood Protection Project
The DFPP is part of the S2S Project which was included as an objective of the current Development Plans for Dublin City Council, and Dun Laoghaire Rathdown County Council and has also been included in the Dublin Docklands Development Authority’s Masterplan and the Dublin Transportation Office’s Platform for Change. The completion of S2S is also a policy within the Governments’ Cycle Policy Framework 2009.
The overriding design parameter of the project is the provision of a promenade, cycleway and flood defence. Coastal Flood Protection measures have also been included as an integral part of the design of the Dollymount Promenade & Flood Protection Project.
This project is currently in the detailed design stage. The Environmental Impact Statement (EIS) was submitted in June 2009 to An Bord Pleanála for Planning Approval. Subject to funding, the project will commence in the summer of 2010.
The design life for the proposed promenade will be 120 years. However, for the design of coastal protection structures a national design standard of a return period of 200 years should be adopted for the design. The extreme high water level (based on Dublin Port) for a return period of 200 years is predicted at a level of +3.13mOD (Malin) for a base year of 2005. According to Dublin Coastal Flood Protection Plan (DCFPP) climate change / sea level rise recommendations, an annual sea level rise of 4.15mm/year should be included in all future designs for flood defence or other structures. This includes an allowance of 0.3mm/year for land subsidence.
Indicative proposals of such defences have been included on the preliminary design drawings.
Sandymount Promenade and Flood Protection Project
The SPFPP is part of the S2S Project which was included as an objective of the current Development Plans for Dublin City Council, and Dun Laoghaire Rathdown County Council and has also been included in the Dublin Docklands Development Authority’s Masterplan and the Dublin Transportation Office’s Platform for Change.
Flood protection is to be a primary function of the proposed new facility and a minimum standard of flood protection based on a 1 in 200 year return period was adopted in line with the current recommendation of the Office of Public Works.