Erosion at Thorpeness has accelerated dramatically with the creation of a quarry shaped section of beach, with around 7 metres of cliff retreat, replacing an area fronted by Gabions (Stone Baskets) backed by cliffs covered with vegetation.
For comparison, this is the same section of beach in 2023.
A number of homes on North End Avenue at Thorpeness are now at risk, with one home-owner being told, if the cliff retreats to within 5 metres of their home, it could be demolished.
This section of beach has been very vulnerable to the strength of the waves for a number of years, with the stone-filled Gabions, frequently broken apart by the waves. Gabions are sea defences that are supposed to attenuate (lessen) the power of the waves.
But frequently the shape of the damaged stone gabions seems to be mimic the shape of the Plunging Waves that so frequently weaken and smash apart the gabions.
A background to the severe erosion, which has occurred for a number of years at Thorpeness, is outlined in a discussion that looks at the interaction between waves and nearshore features such as the Sizewell Dunwich Sandbank System. To consider how such features can influence the erosion and the profile of the beach at Thorpeness. It has been said that around 2 metres has been eroded from the Sandbank system in recent years.
Erosion into fragile sandy cliffs is a well-documented phenomenon, with waves said to “collide” with the cliff surface, causing the rapid removal of sediment and the gouging of notches into the toe of the cliff. Transmitting damage both into and upwards within the cliff structure, causing retreat, sometimes metres inland from the original erosion.
An example of severe erosion at Truc Vet beach in France describes how once the cliff retreat occurs, the new retreat line remains. Even if beach levels accrete (accumulate) sediment in the summer, the profile and bones of the beach, remain weakened, remaining vulnerable to further change once storm waves return. Therefore, it could be said that it is not just the properties that are now at risk, but the whole structure of the beach and section of coast, which has been fundamentally altered and re-worked by the sea.
Solutions to the severe erosion at Thorpeness are not easy as both sections of beach, either side of the rock revetment, are subject to acute erosion.
With a likely contributory factor being the tendency for waves, when they encounter an object, to ‘refract’ and cut around it into the cliff/gabions at either side.
Beach levels are also quite low on the foreshore below the Gabions, with no accretion (accumulation) of sediment, with a steep slope. Such features that can make it easier for waves to travel up the beach and directly hit the sea defences, as on this section of beach, there is very little distance between the sea and the defences.
It is increasingly difficult to access the section of beach subject to severe cliff retreat, as even at low tide, it is frequently covered by sea water. Which obviously means this section of beach can constantly be shaped by the actions of the waves.
The television programme, The Secret Life of Waves, suggested that waves could be understood as moving bodies of energy, rather than sea water. At Thorpeness, the concerns of property owners at immediate risk and those in the wider area will be focused on the implications of the powerful energy of the waves. In the constant contention for possession between the sea and the land.
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