Save Cork City’s plan is to build a tidal barrier now... instead of waiting for the sea to claim the city, writes
AS I write, 85% of the city of Venice is under water.
There have been two deaths and the mayor, Luigi Brugnaro, has described the flood damage as “as indelible wound”. A tidal barrier to protect the city has been built, but is not yet working, due to the delays and corruption that are part of Italy’s political landscape.
Huge urgency is now being attached to making the barrier functional, because Italians understand that what happened on Tuesday night is only a precursor of the floods that climate change will bring.
Cork is Ireland’s Venice. I never fail to think of the Italian city when I cross the south channel of the Lee.
There’s an obvious geological connection. Just like Venice, Cork is built on water, or, more accurately, on marshland, between channels in the Lee Valley.
This gives the city its special character, but makes it vulnerable to flooding, like Venice is. This is especially true as we confront this new era of climate disruption.
In Monday’s TV programme Will Ireland Survive 2050? veteran RTÉ meterologist, Gerald Fleming, sent pulses racing with his computer-generated visualisations of Dublin’s O’Connell St and Cork’s Grand Parade under several feet of water.
You don’t even need visualisations to see waves lapping onto the streets of Cork; you can look at an online video of a man swimming up Oliver Plunkett St in 2014.
There is no time to waste in addressing the city’s acute vulnerability to the new floods of the climate change era.
The director of operations at Cork City Hall, Sean Lynch, picked a bad moment to announce that there will be no independent review of the OPW’s “walls scheme”, by which up to 15km of the city quays would be replaced or surmounted by flood barriers, despite the council’s motion calling for such a review.
The walls plan is 10-years-old and unacceptable in an era when the climate is changing rapidly. Even still, the OPW’s own advice says these walls may be over-topped by flood waters from 2049, in a worst case scenario, or from 2070, in a better scenario.
Being unready for 2050 is one thing; building massive infrastructure, at a projected cost of €140m to €160m, which you know won’t work in the era of climate change, is plain irresponsible. The scheme might not even be completed by the time it is “overtopped”.
“Overtopped” is a nice word, but it hardly conjures up the reality of river water pouring onto the quays from a 4ft-high wall.
The lobby group opposing the OPW’s walls scheme, Save Cork City, provides, in its literature, a scary picture of Edgecombe, New Zealand, largely under water in April 2017 when flood walls were breached.
How much more dangerous will the Lee be if its flow rate is almost doubled, as is envisaged by walls scheme?
Neither does the walls scheme address the fact that Cork is built on wet silt and gravel (or an “aquifier” as it is described by the experts). This aquifier is not only tidal, it is connected to at least eight channels of the River Lee, which were modified by cross-cutting canals from 1090 to 1800. Sinking “cut off walls” associated with the OPW’s flood barriers, and their 46 pumping stations, into a volatile groundwater foundation is “an experiment which is likely to fail”, in the words of consulting geologist, Anthony Beese, in a report commissioned by Save Cork City. Among the limitations of the OPW’s walls scheme is the likelihood that the entire aquifier, stretching across the Lee valley, will be flooded by rising groundwater, regardless of the walls built to protect the inner city island. Disturbing the groundwater may dry out and destabilise historic buildings. It may cause pollution from sewers to build up and discharge.
The OPW scheme envisages the 46 pumping stations counteracting groundwater swells with bored wells and/or chambers to take the excess water, but Beese says no comprehensive investigation of this mechanism has been attempted and that it remains “largely experimental”. The underlying, buried glacial valley is so uneven that it would be impossible to be sure that bedrock had been reached to cut the groundwater from the river, in any case.
In short, the walls scheme disturbs a volatile aquatic environment, which the OPW doesn’t fully understand.
I am not a geologist and neither are most of you.
Surely, most of us agree that a public works project, like the OPW’s walls scheme, which has such massive implications for the city and about which there is much professional disagreement, must be subjected to rigorous public enquiry?
And that such an enquiry should question why such walls should be built, at huge expense to the tax-payer, when the developers themselves say they may be redundant in 30 years’ time, because of climate change?
The OPW itself suggests a tidal barrier at Great Island may be necessary by that point, due to sea-level rise and storm surges.
Save Cork City’s plan is to build a tidal barrier between Mahon and Little Island right now, instead of waiting for the sea to come in and claim the city.
THERE would then be no reason to build walls between the river and the people. There would be little ongoing disruption of the city, at this, the moment when it has had more potential than it has had in a century. One of the most beautiful Georgian riverscapes in the world would be preserved and enhanced. The most recent estimate, from TU Delft, the Netherlands, puts the cost of the tidal barrier at under €200m. Save Cork City argue that it would protect fully 16,000 people, rather than the 2,000 protected by the OPW’s walls. Crucially, the barrier would protect the docklands, which are primed for redevelopment, unlike the walls.
But why should we rely entirely on information commissioned by a lobby group to interrogate the OPW’s plan?
The walls scheme doesn’t have to go through the planning process, because it is, ostensibly, a drainage scheme, covered under the Arterial Drainage Act (1945), despite the fact that it has been called, by UCD academics, “the greatest planned destruction of heritage in the history of the State”.
All Cork City Hall has done to investigate the suggestions put forward by Save Cork City is engage in a Twitter war, rubbishing the group’s ideas.
City Hall says the Minister of State for the Office of Public Works, Kevin ‘Boxer’ Moran, ruled out an independent assessment of the walls scheme just last year, The feeling is widespread that he will give it the go-ahead in the pre-election fever.
Such a move would be outrageous.
The threat of climate change is no reason to dump local democracy. It is only through local democracy that we can fight it.