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TUE, 02 FEB, 2021 - 09:08

Kathriona Devereux: It’s time to think again about flood defences for Cork city


Kathriona Devereux talks to a new group of independent professionals who have entered the debate on the Lower Lee Flood Relief Scheme


An image of what the Lower Lee Flood Relief Scheme would look like at Lapps Quay.


THE issue of the flood relief scheme for Cork has gone off the radar recently.

The walls versus tidal barrier disagreement about how best to protect Cork has escalated to the High Court, with community stakeholder group Save Cork City objecting to the Office of Public Work’s plans. The case is not likely to be heard till the summer.

This time lag could allow for the independent review of the Lower Lee Flood Relief Scheme (LLFRS) that has been voted for twice by Cork city councillors.

A new grouping of independent professionals that include a chartered engineer, quantity surveyor, architect, geologist, lawyer and environmental activist has entered the debate. Last week the Lee Engineering and Environment Forum (LEEF) launched their website ( with forensic professional analysis of the proposed flood relief plans for Cork city.

The OPW says the LLFRS will cost €140m and protect 900 homes and 1,200 businesses. When stakeholder groups and academics proposed a tidal barrier in the harbour instead of flood walls in the city, the OPW costed tidal barrier options. The most recent OPW report in 2018 said a tidal barrier at Little Island would cost €1billion.

“The Lee Forum website hosts three video lectures highlighting numerous issues. If you care about the future of Cork city, you should watch them.


LEEF experts have painstakingly examined the OPW’s published cost estimates for the walls scheme and for the tidal barriers. They claim there are lots of holes.


I’ve watched enough episodes of Room To Improve and read enough about the National Children’s Hospital to know having budgets and design specifications rock solid before commencing any building project is good common sense. When undertaking the biggest flood relief scheme in the State, it is imperative that the budget reflects the design.

LEEF experts measured and costed all items in the detailed drawings proposed by the OPW and compared the published budgets with the nicely rendered artist impressions at the Kingsley, Fitzgerald’s Park and Morrison’s Island. They claim the OPW underestimated the costs of the Walls scheme by at least €143m, to protect the north and south docklands would push the price up beyond €400m. They say the pleasant-looking boardwalks and multi-coloured granite paving and bollards are simply not priced, the promised expenditure of €20m to repair historic quay walls is not in the budget.

One example is the 42 pumping chambers proposed with the Walls scheme. The OPW has allowed €75,000 each, or €3.15m total, for pumping stations. LEEF consider this a gross underestimation. In 2016, a pumping chamber in Clonakilty cost €504,000. Furthermore, the OPW’s budgeted “maintenance costs” of 1% of construction costs bears no relationship to the work involved in crews installing 1km of demountable flood defences, maintenance of 42 pumping stations and associated generators, replacement parts and power, trucks, storage of demountables and maintenance of non-return valves.

Given the complex urban environment where these stations will be installed and looking at the price tags of comparable projects, LEEF professionals think a more realistic estimate would be €335,000 per pumping station — a total cost of €21.2m. 670% more than the OPW are budgeting!

Conversely, when LEEF professionals ploughed through the OPW design and budgets for tidal barriers, they found expensive superfluous elements that drove up the projected costs. The latest OPW whole life costing (cost to build and operate) of a tidal barrier at Little Island was €1.02 billion.

“From 2014 to 2018, tidal barrier cost estimates in different reports shot up. This is taxpayers’ money —I’d like to be sure of the maths.


Extras such as two navigable flood gates (Rotterdam, the busiest port in Europe, has one), unnecessary motorway tidal gates, and excessive sluice gates all drove up the costings. LEEF’s analysis was that a pared back, but perfectly functional and safe, design of a tidal barrier at Little Island would actually cost between €200 and €300m.

This would also protect the 14,000 properties proposed on the city and Tivoli docklands. (The Walls scheme just protects the city — to include the additional flood protection of the redeveloped docklands would increase costs beyond €400m.) LEEF also argues that the Walls project is fraught with multiple risks which have been downplayed or ignored.

Another presentation raises the issue that the dogs in the streets know — when Cork floods, the water comes up shores, manhole covers, sinks and toilets, not just over the top of quay walls.

LEEF professionals argue groundwater flooding and the complex geology under Cork city has not been adequately considered in the overall design of the flood relief scheme.

The OPW’s plans do not address the water that sits under our streets in old covered water channels, in perched water sitting on top of estuarine mud or in gravel or limestone aquifers.

Imagine if we ripped up our city to build these walls to protect us from river and tidal flooding, but still experienced groundwater flooding!

There’s also the non-trivial matter that the Walls scheme doesn’t fully factor sea level rise. Cork is going to need a tidal barrier anyway by the end of the century, if not sooner, to deal with the consequences of our warmed planet.

So if the Walls scheme will actually cost €283m and the Tidal Barrier could actually cost €200m, then surely the whole Lower Lee Flood Relief Scheme should be subject to an independent evaluation and recalculation to make sure we don’t commence works on another costly debacle.


Article published by Echo:

Kathriona Devereux: It’s time to think again about flood defences for Cork city. Available at:

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