By PAUL RIDDELL
SEA LEVELS around Shetland will rise in the next 75 years by more than elsewhere in Scotland, according to a major new study into coastal flooding published this week.
The authors of the Dundee University report predict an increase in the Northern Isles of 30cm by 2080 compared with 20cm for the Clyde estuary and 28cm in Moray and Aberdeenshire.
But they say sea levels in Scotland will not be as high as other in parts of the world due to the fact that the land surface is still continuing to rise following the melting of the last ice sheet around 10,000 years ago.
This geological “squashed cushion” effect is estimated to shave as much as 1mm off the annual rise in sea levels around Scottish shores.
However, the projected rise will force planners to consider building flood protection defences like the sea wall next to the roundabout on the South Road at Clickimin in some vulnerable areas. Storm surges will also be a major concern.
The Scottish government is currently preparing a Flood Risk Management Bill and the report calls for strategic, long-term planning to replace reactive, stop-gap solutions while recognising that local authorities have limited resources.
SIC flooding and coastal protection engineer Jonathan Duncan said the figures in the report were in line with those behind current council policy, which is that anything built below the five-metre contour line has to have a full, independent risk assessment, both for coastal and on-land flooding.
Mr Duncan said that in general terms the council tried to discourage new development below this line. The council’s policy is regularly reviewed, and reports such as that published this week would inform deliberations over new policy. It is hoped that some of those behind the report may be able to travel to Shetland to discuss their findings.
Two years ago Sepa published maps that predicted which areas of Scotland would be most affected if sea levels rose by varying degrees. These are also used by the SIC.
The report, entitled Coastal Flooding in Scotland: A Scoping Study, was carried out by experts from the School of Social and Environmental Science/Geography at Dundee. It also looked at floods in different parts of Scotland dating back to 1849.
The authors observe that storms driven in from the Atlantic during periods of strong westerly winds were the main cause of flooding. The wave action produced by these winds plus high tides and storm surges were to blame.
Over the past few decades, water levels 50-60cm above the highest predicted tide have been recorded at Aberdeen, Lerwick and Stornoway and 120cm at Millport on the Clyde.
Professor Alan Werritty, who led the team compiling the report, said: “Until recently, coastal flooding has attracted less attention in Scotland than floods affecting cities and the countryside.
“With sea level rise and the threat posed by storm surges, now is the time to assess the risk posed by coastal flooding and ways of managing that risk.”
RSPB Scotland freshwater policy officer Andrea Jonstonova said: “Climate change and sea level rise is going to increase the risk of coastal flooding in future, putting additional pressure on existing coastal defences and threatening coastal habitats and wildlife.
“We need to adapt to this change in a sustainable way and seek natural, long-term solutions like managed coastal realignment. Such an approach has the potential to ease the risk of flooding and create valuable new wetland habitat for breeding birds. There is currently a lack of innovative, sustainable projects to address the increased threat of coastal flooding and sea level rise. This should be the focus of the new Bill.”
Prof Werritty said consultation with local authorities and other bodies that manage coastal flooding yielded a number of different operational and policy issues. “In operational terms, the number of local authority coastal flood defences is relatively small, but several new or enhanced defences are in the pipeline. Alternative strategies for managing risk based on emergency action, land use planning, raising the awareness of flood risk by the public and managed retreat away from existing shorelines are emerging, but these tend to be localised and piecemeal.”
Prof Werritty said in terms of policy, a proposed national body to oversee the management of flood risk was welcomed and better guidance sought on implementing existing and new legislation.