Sea Defences & Coastal Protection
The responsibility for looking after the problems of flooding arid erosion along our coastline is complicated.
The legal position behind the various powers, duties and obligations has evolved over hundreds of years, involving the Environment Agency, local authorities and local landowners.
Most of the coastal work carried out by the Agency and Local Authorities can be divided into sea defence and coast protection.
Sea defence works generally reduce the risk of low-lying land flooding from the sea.
Coast protection works generally reduce the rate of erosion of cliffs by the sea.
While the Environment Agency does not have a duty to provide sea defences, it does have permissive powers to take action. District councils and unitary authorities can undertake coastal protection work. The Environment Agency works closely with these authorities to ensure that where action is taken it is coordinated along the coastline.
Powers to do work exist but strict economic and environmental criteria have to be met. They are linked to what are called 'benefit to cost studies' and 'environmental assessments.
This process ensures the Agency and local authorities invest wisely on behalf of the nation.
It these criteria are met and the necessary external approvals obtained, the scheme will enter the Flood Defence Committee programme and be undertaken when funds permit, according to the priority assigned to the scheme.
THE PEVENSEY BAY COASTLINE
Pentium Coastal Defence Ltd on behalf of the Environment Agency generally maintains the Pevensey Bay coastline. This area of low-lying coast between Beachlands and Cooden is known as the Pevensey Beach Coastline.
The land to the west is looked after by Eastbourne Borough Council and consists of the higher land of the urban area of the town apart from a short 300m section maintained by the Agency - known as the Crumbles.
To the east Rother District Council looks after the low cliffs fronting the town of Bexhill. In practice the Agency, Eastbourne and Rother work together very closely to protect the coastline. The entrance to Sovereign Harbour is a breach in the coastline that prevents shingle movement along the coast.
As the coastline is exposed to the power of the sea it tries to change under the force of the waves. This change is known as coastal processes or 'geomorphological change'. It may not be possible to provide sea defences that will survive in the longer term. Our coastline is continually responding to such pressures from the sea and our attempts to intervene and influence these changes have met with mixed success.
Soft defences of sand and shingle can be very effective in absorbing and breaking up the power of the waves. This is particularly so where flood protection rather than erosion prevention is the main aim. Groyne fields can help to retain the shingle but open beaches are more effective in some circumstances.
THE PEVENSEY BAY SEA DEFENCES
The Pevensey Bay shingle sea defences are nearly 9 km long. The crest of the sea defences lies at about 6 m A.O.D. and in most cases the shingle bank extends seawards around 45 m. The beach then becomes sand and is of a shallow gradient. Over the period 1973-96 there has been no discernible change in crest height and the shingle ridge is overall as wide as it has been for a number of years. There are over 150 timber groynes along the frontage, many of which are now in a relatively poor state of repair
The sea defences provide protection from the permanent flooding of a 50 square km area including Pevensey Bay, Normans Bay, Langley, Westham and parts of Pevensey itself. Within this area there are more than 2000 properties, important recreational and commercial sites, transport links (main road and railway), wetlands of international importance and two important nature reserves (Hooe Flats and Pevensey Levels). Should there be a serious breach of the sea defences then all these sites could be flooded.
REDUCED RISK OF FLOODING
It is important to remember that the Pevensey Bay sea defences were built to reduce the risk of flooding to the low-lying land across the Pevensey Levels. Many of the current developments such as caravan sites on low lying land and indeed properties built into the crest of the sea defences are to a degree incidental to this. The defences were not built with protecting these developments in mind.
The Environment Agency maintains the Pevensey Bay frontage to reduce the risk of the Pevensey Levels again becoming a lowland tidal marshland. In this way the Agency reduces the risk of flooding and damage to property, roads, railway and the unique ecology of the Levels. Given the nature of the construction there has always been a risk of defence overtopping and temporary breach. As a result there has been a long history of temporary flooding problems with the last reported major flood being in October 1999 when overtopping of the defences caused damage to some of the crest top properties. There are records of similar events in 1926, 1935 and 1965.
On Christmas Eve 1999 many local residents were evacuated because of the prospect of high tides and high winds. A change of wind direction provided some relief and the worst fears were to prove unfounded. Nevertheless, the future of this area is likely to be affected by problems of high sea level and storms.