Crumbles East Sussex - summary

The Crumbles shingle structure is derived from rapid accumulations of gravel derived from the seabed around the twelfth century. Growth continued until about the seventeenth century when the position of the coastline was some 2km seaward of its present position (Jennings & Smyth 1990). Since then the coast has receded to a position similar to that in 1844 despite and has been kept in place since then by an extensive groyne field. The site has also been the subject of considerable loss and damage to the surface shingle (see figure opposite).

Caption: Figure showing the progressive loss of surface shingle from the 'Crumbles', East Sussex to a variety of human activities.

As well as major interference the the shingle structure itself, building the 'Sovereign Harbour' in 1993 resulted in severe erosion to the east (downdrift from the harbour breakwaters) in Pevensey Bay. To counteract these effects shingle recharge has been instigated in front of Eastbourne to the west and along the Crumbles foreshore. A new series of groynes has also been constructed.

Comment: Although in 1987 an engineering report concluded that the "beaches of the Crumbles were stable ....and could be engineered so that no further erosion took place." This view was based on a review covering only ten years of beach profile data. It is argued that, as the case of Porlock Weir also shows, much longer timescales are needed (measured in 100s - 1,000s of years) when assessing the 'stability' of beaches (Orford et al. 2001).

References

Jennings, S.C. & Smyth, C. 1990. Holocene evolution of the gravel coastline of Eastt Sussex. Proceedings of the Geologists' Association, 101., 213-214.

Orford, J.D., Jennings, S.C. & Forbes, D.L. 2001. Origin, development, reworking and breakdown of gravel-dominated coastal barriers in Atlantic Canada: future scenarios for the British coast. In: Ecology & Geomorphology of Coastal Shingle, eds.Packham, J.R., Randall, R.E., Barnes, R.S.K. & Neal, A.Westbury Academic and Scientific Publishing, 23-55.