The latest flash flooding events to hit three major Cork towns have thrown a spotlight again on contentious flood defence schemes and raised questions about the €150m scheme proposed for Cork City — the largest single investment in flood defences in the history of the State.
Why, after all the investment in flood defences in Bandon and Skibbereen, were streets under water? If they can't cope with flood defences, what will happen in Cork City? Why has it taken so long to deliver a flood relief scheme in Bantry? If these towns can’t cope with freak summer storms, how will they cope this winter?
Critics of the Office of Public Works’ (OPW) contentious €16m scheme nearing completion in Bandon, with its hugely disruptive interventions in the river Bandon, its €18m scheme in Skibbereen, which features ugly concrete-clad culverts, and its controversial proposed €150m scheme in Cork City, have claimed that the recent flood events in Skib and Bandon are proof that their flood relief schemes didn’t work, and that the one planned for the city won’t work.
It’s an easy narrative for critics but it’s based on a false premise.
Yes, the various agencies involved in flood relief works have questions to answer about the pace of delivery.
But the key point is that the flood relief schemes, like them or not, didn’t fail.
The recent floods are all linked to storm drainage issues.
For those business and homeowners facing yet another clean-up, that's a moot point. Flooding is flooding wherever it comes from.
But it's important to understand why two towns with flood relief schemes saw floodwaters on the streets again, and why a third town is still waiting for a solution.
In Skibbereen, where some €18m has been invested in flood relief works, streets flooded during Storm Ellen last week when a culvert and storm drain at ‘The Cutting’, just off Bridge St, was overwhelmed when rainfall reached 40mm an hour.
During the delivery of the overall flood defence scheme, a number of areas in the town were identified where surface water drains could have had the potential to cause flooding.
Because the larger flood relief scheme was already underway as part of an OPW contract, these areas were pursued separately as ‘minor works’ by Cork County Council.
The OPW provided funding for works at The Cutting — the construction of a large concrete chamber with a specially manufactured screen to cover an area where the overground drain entered into a piped drain.
The work was interrupted by Covid-19 but there was criticism when it emerged that installation of the screen — which could have mitigated last week’s flooding — was delayed just hours ahead of Storm Ellen’s arrival.
The screen was installed the day after— too late for those hit by flooding. But it should mitigate against future flooding.
Bandon was hit the same night, and again during Storm Francis on Monday night, when more than 53mm of rain fell over a 24-hour period — most falling later in the night.
Here, two separate projects to mitigate flood risk are underway.
The OPW is overseeing the flood relief scheme, which is nearing completion, while Irish Water is overseeing a separate main drainage scheme to upgrade the town’s sewer and stormwater drainage capacity.
The Irish Water scheme has its critics too, with constant complaints about diversions and disruption as roads are dug up.
It was the lack of capacity in the town's drainage system which contributed to the two recent flood events, with indications that the drainage and sewer network at two key areas was just overwhelmed by the sheer volume of rainfall.
The OPW said the main aspects of its scheme are functioning and performed well during the flood events.
On Monday night, the level of the river Bandon was relatively low and most drains were able to discharge by gravity to the river.
It is only when the river level is higher, that pumping stations installed as part of the OPW's scheme will kick in as required.
The combination of circumstances that would lead to the activation of pumping stations just did not arise on Monday.
The pumping stations didn't fail. The circumstances just didn't combine to activate them.
The authorities insist that when the drainage upgrades are done, the system will have significantly increased stormwater capacity.
In Bantry, an overwhelmed culvert contributed to major flooding which hit over 50 premises and damaged streets.
Cork County Council said it’s working closely with the OPW and Irish Water to develop and deliver a solution to “a complex, stone construction culverted drainage system” with many connections, including utilities, public and private, and which is further complicated by its proximity to the foundations of private buildings, and its location under roads and footpaths.
The tender process for the consultancy contract is at an advanced stage and is expected to issue in the coming weeks, the council said.
That’s little consolation to affected home and business owners, who face an anxious winter.
But emergency short-term measures are required in Bandon and Skib to ensure that culverts and drains aren't overwhelmed before the upgrade works are finished.
The businesses in Bantry need a solution and need one fast.
Then, pending ministerial approval, it will be Cork City's turn.