A critical part of the emerging South Galway Flood relief scheme includes significant reconstruction works on the M18 motorway to ensure that there is enough capacity for the flood relief scheme to be viable.
The concern over the proposed flow capacity during extreme flood events was highlighted to TII(then the NRA) in reports dating as far a back as 2010. These reports called for NRA/TII to ensure “properly sized and placed culverts” that would ensure transition of flood waters under the M18 at Kiltartan/Raheen. (See ‘M18 Motorway design not future-proofed for flooding‘) TII were asked to include culverts in addition to what was being proposed under the M18 to ensure capacity for significant flood overflow coming from the confluence of the 3 rivers, sourced in Slieve Aughty mountains in South Galway.
In a 2011 OPW report, it was mandated that much larger culverts should be installed underneath the motorway.
it is considered absolutely essential that the design of the new motorway … provides a 100 m3/s culvert where the M18 crosses the Corker overflow to avoid any flow restrictions.
REVIEW OF THE SOUTH GALWAY FLOOD STUDY REPORT, OPW 2011
https://assets.gov.ie/47184/d359f629d1784e6ba7126bc9e6d80798.pdf
Unfortunately, while NRA/TII had access to these reports, and they may have considered them, they did not implement the right solutions. What they did do, was kick the can down the road and push responsibility for dealing with this at a future date.
That date has come quicker than TII imagined and they are now faced with having to construct a brand new big culvert under the motorway (8.5m wide and 2.5m high). As you can imagine this is very disruptive and costly but a key concern is that the TIIs approach could threaten the whole project.
Firstly, TII are dragging their heels with this and are not in the critical path of the project completion. TII has been provided with all findings from the project, including details of the March 2020 flood event but have been very slow to conclude a detailed design. This is delaying the environmental impact analysis and as such, at this stage, the whole project. TII indecision is now delaying the South Galway Flood relief scheme
Secondly, we are very concerned that TII will demand costs of reconstruction of a new culvert under the existing M18 from the South Galway Flood Relief Scheme, which is already challenged from a cost-benefit aspect. TII kicked the can down the road so the budget for fixing the M18 (as it should have been done in the first place ) should fall within TII/PPP budgets and not take away from the South Galway Flood Relief Scheme.
This culvert could have easily been included in the original design at a fraction of the cost and now (depending on chosen approach), the M18 may have to closed for weeks as a section will need to be demolished, a culvert inserted and then the M18 will need to be reconstructed.
Well sized and placed culverts under the M18 motorway were always part of the solution and recommended as far back as 2010 and are an integral part of a future-proofed M18. Mistakes have been made in the past by not future proofing this flood relief channel but the South Galway Flood Relief project should not bear the burden of this shortsighted situation.
We have asked TII for update and they have responded that they have delivered a report with options to Galway County Council.
We would ask TII to accelerate the decision making process here and remove any burden of costs of the culvert from the South Galway Flood Relied scheme
We are asking Galway County Council, our county councillors and elected representatives to demand that TII speedily conclude their designs to the project can proceed ahead and also that they remove any burden of budget from the South Galway Flood Relief project.
David Murray,
Chair, South Galway Flood Relief Committee
South Galway Floods 