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Campaign for Coastal Defence
Selsey Life (November 2009)
Shingle, lovely shingle!
At the time of writing, October’s first spring tides have passed off without any problems: the seas weren’t too rough, and at Medmerry the Environment Agency prepared the shingle bank in advance.
But unfortunately, the constant attrition of the sea wears down the wooden groynes and even the reinforced concrete sea walls that form part of our coast defences. It also displaces the other key part of our coast defences: our shingle.
Ask a visitor which of our sea walls is “better”: East Beach or West Beach? Almost all say that West Beach is better, because it’s higher. That is an understandable reaction but it’s wrong for various reasons, two of them connected to shingle.
Firstly, the sea walls at East and West Beach are built to almost exactly the same height above sea level (roughly 5.3m above “Ordnance Datum”). West Beach sea wall simply appears to be higher, because the beach in front of it is lower.
For decades, the shingle on west Selsey’s beaches (from about Hillfield Road westwards), has gradually moved westwards by wave action. Although the groynes slow down this process, it still takes place (the shingle ends up down at Bracklesham and beyond). In recent times no fresh shingle has arrived on west Selsey’s beaches from offshore, as it once did, helping replenish the beach. As a result, the beach level has dropped so if you’re standing on the beach, the wall looks higher.
This leads to the second reason why the western sea wall isn’t in as good shape as the eastern one. Imagine if you built a nice solid wall, then you excavated a great big hole alongside it, almost down its foundations. This is essentially what the sea has been doing alongside west Selsey’s sea wall.
The eastern sea wall generally has plenty of shingle in front of it, protecting its foundations and allowing waves to expend their energy on the shingle, rather than on the wall. By contrast the western wall has very little shingle in front of it, so it is less stable. The result can be failure: in March 2007 a 40m section of the wall collapsed, its foundations sliding seawards. It cost £600,000 to rebuild. Unfortunately we’re most unlikely to get government funding to do that again, and the underlying problem of beach levels has not been resolved.
Putting replacement shingle on the beach is a solution, but where could you get it, affordably and sustainably? A simple answer is to find where it is disappearing to - in our case, Church Norton and Bracklesham - and haul some of it back (you wouldn’t take too much: you don’t want to cause problems elsewhere on the coastline).
These accumulating shingle “stores” are a natural resource. SOS believes the community should have the right to harvest them responsibly. The shingle there could be a vital part of the solution to maintaining Selsey’s sea walls into the future. It’s estimated the cost of our maintaining our defences will be £30m over the next 20 years. If a natural resource is available right on our doorstep which could help us in this, we should be allowed to use it. Conservation designations and objections currently make this difficult, but we believe that it is high time to review this situation.