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Dublin And Cork Are Sinking

29th November 2022
Time for a Sinking Fund? One cartographer’s version of Dublin’s chronic flood risk by 2050
Time for a Sinking Fund? One cartographer’s version of Dublin’s chronic flood risk by 2050

Yet again we’ve had a journalist in Ireland’s “Paper of Record” ventilating at the weekend about the widely-held belief that not only are world sea levels rising – which we all accept – but that these absolute sea level rises are happening twice as quickly in Dublin and Cork as they are elsewhere, which is hydrographic nonsense.

We also had a noted TV architect musing in print on how sensible it would be to “re-claim” land along Dublin’s secondary Tolka Estuary - presumably on its south side - in order to provide housing of a popular kind instead of the generally-loathed apartment blocks. This would thereby provide highly-desirable yet affordable family living beside the seaside.

In all, both pieces provided a fascinating insight into how words can be used in a secondary way to set the tone of any opinion piece. For instance, there’s the persistent bandying about of “re-claiming land from the sea”. That’s off target. Once upon a time, the world was all sea. So if we create new land, it’s infill, indeed it’s arguably theft against nature. But it’s certainly not “re-claiming”, even if that’s a difficult position to maintain when we’re up against the Biblical imperative of St John the Divine with his anticipatory Book of Revelations assertion that “there would be no more sea”. 

MAINTAINING EXISTING WATERFRONT SUBURBS

Be that as it may, the idea of some infill along the south side of the Tolka Estuary is attractive, as it would be a completely new parcel of land which interferes with no-one else’s established seafront access. As it is, many of the schemes for infill in Dublin Bay have blithely claimed over many years that they would provide people with “new seaside homes”. But the proposed locations of these new homes would mean that some long-established waterfront suburbs are no longer beside the sea at all, which rather negates the good intentions of the basic projects.

A proposed infill for new housing along Dublin’s Tolka Estuary (right) might be acceptable if it were on the south side, thereby avoiding the sea access infringement of established waterfront suburbs in Clontarf. But it has to be remembered that the daily tidal draining of the extensive Clontarf Basin provides a useful scour-dredging effect for the entrance to Dublin Port via the River LiffeyA proposed infill for new housing along Dublin’s Tolka Estuary (right) might be acceptable if it were on the south side, thereby avoiding the sea access infringement of established waterfront suburbs in Clontarf. But it has to be remembered that the daily tidal draining of the extensive Clontarf Basin provides a useful scour-dredging effect for the entrance to Dublin Port via the River Liffey Photo: courtesy Dublin Port

But, that said, it has to be borne in mind that the twice daily exit of the tide from the currently extensive “Clontarf Basin” in the Tolka Estuary plays a significant role in the scouring of the entrance of the sea channel into the Liffey – in other words, it’s a freely available dredging process to facilitate the continuing and vital activity of our largest port.

The other point about the relative sea levels in Dublin and Cork has been allowed to pass unchallenged so many times that we wonder if anyone bothers to read these newspaper think pieces with any real attention at all. For sure, the global sea level at the Equator does come in a bit higher than on the rest of the planet, an effect of the world’s daily rotation. So I suppose we should be grateful that it doesn’t spin off the waters of the Pacific Ocean in their entirety into Outer Space. But it does mean that global sea level rising is a much more acute problem in low-lying Polynesian island nations.

SEA LEVEL IS AN ABSOLUTE IN IRELAND

However, within an island the size of Ireland, there is no significant difference between the absolute heights of the sea north and south, east and west. So when it’s recorded that the sea has risen globally by 70ml during the past 20 years, but that in Dublin and Cork tide recorders are showing a 20 year rise of 130ml, then it can only mean that Dublin and Cork have been quietly sinking by 60ml since 2002.

As has been demonstrated in recent years, Cork Harbour flooding is influenced by many factors, but this projection for 2050 is simply based on rising sea level. As has been demonstrated in recent years, Cork Harbour flooding is influenced by many factors, but this projection for 2050 is simply based on rising sea level. 

The relative rise and fall of land masses is a geological and hydrographic fact. As the most recent ice age retreated to take away the ice-sheet weight from Ireland, some areas of land popped up almost visibly to gives us raised beaches and suchlike. And it’s reckoned that the geography of Greenland will need significant re-drawing as the weight of its enormous, many-miles-deep ice fields disappears - that is, if there’s anyone still around to take the necessary readings.

But meanwhile, in Ireland, we have to accept the implications of the fact that our Official Capital City and our Real Capital City are quietly going under. Knowing that it was the weight of ice which pushed down many parts of Ireland in times past, perhaps these modern localized tendencies could be blamed on the weight of self-importance in Dublin, and the weight of assumed superiority in Cork.

While admitting the vast civic and human problems which it would bring, rising sea levels in the Dublin area may provide some interesting opportunities – for instance, it might be useful to own the location of a potential fortress/customs station for the re-born Duchy of Howth beside the new watery frontier at Sutton Cross. While admitting the vast civic and human problems which it would bring, rising sea levels in the Dublin area may provide some interesting opportunities – for instance, it might be useful to own the location of a potential fortress/customs station for the re-born Duchy of Howth beside the new watery frontier at Sutton Cross. 

Whatever, it might help the debate and the planning in some way if it could be accepted that almost half of the relative sea level rise in Dublin and Cork is due to area subsidence, while the other half is due to absolute global sea level rises. Thus it really is time that we brought in Dutch experts to advise in Dublin and Cork on how best to deal with the fact that the apparent tide level in these cities is rising twice as quickly as anywhere else.

The Dutch approached the problem of most of their country being increasingly below sea levels by many means, not least in ensuring that they have the tallest population in all Europe. If we’re going to keep our heads above water in Cork and Dublin, a selective breeding programme should be introduced immediately to raise the national height. That said, having been with some of the grandsons at the weekend, I think it may have already been quietly under way for the past sixteen years. There’s evolution for you.

Published in Dublin Bay, Cork Harbour
WM Nixon

About The Author

WM Nixon

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William M Nixon has been writing about sailing in Ireland for many years in print and online, and his work has appeared internationally in magazines and books. His own experience ranges from club sailing to international offshore events, and he has cruised extensively under sail, often in his own boats which have ranged in size from an 11ft dinghy to a 35ft cruiser-racer. He has also been involved in the administration of several sailing organisations.

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Dublin Bay

Dublin Bay on the east coast of Ireland stretches over seven kilometres, from Howth Head on its northern tip to Dalkey Island in the south. It's a place most Dubliners simply take for granted, and one of the capital's least visited places. But there's more going on out there than you'd imagine.

The biggest boating centre is at Dun Laoghaire Harbour on the Bay's south shore that is home to over 1,500 pleasure craft, four waterfront yacht clubs and Ireland's largest marina.

The bay is rather shallow with many sandbanks and rocky outcrops, and was notorious in the past for shipwrecks, especially when the wind was from the east. Until modern times, many ships and their passengers were lost along the treacherous coastline from Howth to Dun Laoghaire, less than a kilometre from shore.

The Bay is a C-shaped inlet of the Irish Sea and is about 10 kilometres wide along its north-south base, and 7 km in length to its apex at the centre of the city of Dublin; stretching from Howth Head in the north to Dalkey Point in the south. North Bull Island is situated in the northwest part of the bay, where one of two major inshore sandbanks lie, and features a 5 km long sandy beach, Dollymount Strand, fronting an internationally recognised wildfowl reserve. Many of the rivers of Dublin reach the Irish Sea at Dublin Bay: the River Liffey, with the River Dodder flow received less than 1 km inland, River Tolka, and various smaller rivers and streams.

Dublin Bay FAQs

There are approximately ten beaches and bathing spots around Dublin Bay: Dollymount Strand; Forty Foot Bathing Place; Half Moon bathing spot; Merrion Strand; Bull Wall; Sandycove Beach; Sandymount Strand; Seapoint; Shelley Banks; Sutton, Burrow Beach

There are slipways on the north side of Dublin Bay at Clontarf, Sutton and on the southside at Dun Laoghaire Harbour, and in Dalkey at Coliemore and Bulloch Harbours.

Dublin Bay is administered by a number of Government Departments, three local authorities and several statutory agencies. Dublin Port Company is in charge of navigation on the Bay.

Dublin Bay is approximately 70 sq kilometres or 7,000 hectares. The Bay is about 10 kilometres wide along its north-south base, and seven km in length east-west to its peak at the centre of the city of Dublin; stretching from Howth Head in the north to Dalkey Point in the south.

Dun Laoghaire Harbour on the southside of the Bay has an East and West Pier, each one kilometre long; this is one of the largest human-made harbours in the world. There also piers or walls at the entrance to the River Liffey at Dublin city known as the Great North and South Walls. Other harbours on the Bay include Bulloch Harbour and Coliemore Harbours both at Dalkey.

There are two marinas on Dublin Bay. Ireland's largest marina with over 800 berths is on the southern shore at Dun Laoghaire Harbour. The other is at Poolbeg Yacht and Boat Club on the River Liffey close to Dublin City.

Car and passenger Ferries operate from Dublin Port to the UK, Isle of Man and France. A passenger ferry operates from Dun Laoghaire Harbour to Howth as well as providing tourist voyages around the bay.

Dublin Bay has two Islands. Bull Island at Clontarf and Dalkey Island on the southern shore of the Bay.

The River Liffey flows through Dublin city and into the Bay. Its tributaries include the River Dodder, the River Poddle and the River Camac.

Dollymount, Burrow and Seapoint beaches

Approximately 1,500 boats from small dinghies to motorboats to ocean-going yachts. The vast majority, over 1,000, are moored at Dun Laoghaire Harbour which is Ireland's boating capital.

In 1981, UNESCO recognised the importance of Dublin Bay by designating North Bull Island as a Biosphere because of its rare and internationally important habitats and species of wildlife. To support sustainable development, UNESCO’s concept of a Biosphere has evolved to include not just areas of ecological value but also the areas around them and the communities that live and work within these areas. There have since been additional international and national designations, covering much of Dublin Bay, to ensure the protection of its water quality and biodiversity. To fulfil these broader management aims for the ecosystem, the Biosphere was expanded in 2015. The Biosphere now covers Dublin Bay, reflecting its significant environmental, economic, cultural and tourism importance, and extends to over 300km² to include the bay, the shore and nearby residential areas.

On the Southside at Dun Laoghaire, there is the National Yacht Club, Royal St. George Yacht Club, Royal Irish Yacht Club and Dun Laoghaire Motor Yacht Club as well as Dublin Bay Sailing Club. In the city centre, there is Poolbeg Yacht and Boat Club. On the Northside of Dublin, there is Clontarf Yacht and Boat Club and Sutton Dinghy Club. While not on Dublin Bay, Howth Yacht Club is the major north Dublin Sailing centre.

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