Billion Pound Sea Wall for Norfolk?

An ambitious idea for an enormous 27 mile long offshore protective sea wall enclosure extending from Great Yarmouth has been proposed by Mike Evans, Chairman of the Royal Yachting Association and current President of the Norfolk and Suffolk Boating Association, who also represents private boat owners on the Broads Authority.

The proposition is claimed to protect The Broads and low laying inland villages and communities, provide fresh water for irrigation and prevent salination of the inland waterways, create jobs and provide windfarm emplacement and further protect our shoreline, beaches and sand cliffs from further erosion. It is not unprecedented as major projects such as Holland's Flevoland was reclaimed from the sea together with the Dutch freshwater Islemeer, a 400-plus square mile shallow lake in the central Netherlands, both of which were once the saline inland Zuiderzee.

But The Netherlands has a very different attitude towards such forward planning, whilst in the UK the defeatist principle embodied by 'Managed Retreat' and permitting the continuity of offshore dredging is in vogue. Indeed it is this, as well as Britain's serious economic situation that may defeat the proposed project. The needed support and financial backing for such a strategy is highly unlikely in the UK's current economic climate and the continued government policy of aiding and backing continued erosion under the dictates of the 'Managed Retreat' and 'Shoreline Management Plan' policies are set in concrete at this time. Sadly, we do not live in Holland or coastal Europe with their progressive positive and protective policies, but suffer a negative and defeatist attitude from all the myopic bodies that have power over our disappearing coastline.

Furthermore, sea rise alone is a relatively minor component in the threat to our coastline, Broads and inland villages. We have a far greater and more meaningful threat, that of erosion due to huge seabed mining offshore. We currently have sea-level rise of 3.2mm per annum, this added to by 2mm of sinkage annually, giving an equivalent of a sea rise of 5.2mm per year. One would thus have expected an effective sea rise of (3.2 + 2) x 35 = 182mm, i.e. 18.2 cm over 35 the years since 1972 when east coast dredging began in earnest. This level could be slightly increased due to the degraded climate that is producing more erosive waves due to more frequent stronger and longer lasting northerly winds. On an average 1 in 20 beach slope the 35 year 18.2cm sea rise would have produced a sea incursion of the mean high tide mark of 18.2 cm x 20 = 3.64 metres, perhaps allowing that little more for the worsening climatic conditions of global warming. In fact the mean rate of approach has been between six and twenty times this, now with far deeper water offshore and waves right to the sea wall and dune front at many points along much of the East Anglian coastline.

So it is not so much that the sea has risen but that the beaches have dropped, so permitting the sea over them giving a far nearer mean tide mark. This has been brought about directly by the impact of government backed offshore aggregate dredging, as is given on this website under 'Marine Aggregate Dredging' to be found at www.marinet.org.uk/mad/madbrief.html and our treatise on Coastal Defences 'Why Canute Failed' to be seen by going to www.marinet.org.uk/coastaldefences/canute.html.

Between three and five metres of sand and shingle have been stripped from a massive area of the sea bed off the greater Great Yarmouth area. This correlates with the exposure and fracture of the Scroby Wind Turbine power feed cables, once trenched and covered three metres deep in the seabed, which were left exposed and dangling two metres above it following nearby seabed mining. Such underminement, as already evidenced by the base scour of the Winterton to Happisburgh concrete sea wall and the loss of our beaches, dunes and sand cliffs along the vast majority of the East Anglian coastline would undoubtedly come about to an even greater extent seriously undermining any wall built in even closer proximity to the dredging sites.

Thus, whilst we might well approve of the brave concept, we must fear that in practical terms there will be found not only little support but much opposition. The rewards to be gained by the dredging companies, the Crown Estate and the Treasury by the continuing release of aggregate supply from our beaches, dunes and sand cliffs act as a distinct impediment to any plan that prevents their demise.

The original 12th January '10 press article on the subject entitled "Could £1bn sea wall plan be the salvation of Norfolk?" can be read on the EDP24 website and you can take part in a web poll by going to the Anglia Afloat website by logging on to www.angliaafloat.co.uk.