The consortium, Pentium Coastal Defence Ltd (PCDL), also includes marine construction specialists Dean & Dyball and J T Mackley & Co as well as Mouchel Consulting.

The Pevensey Bay Sea Defences contract is a pathfinder project, so its success or failure is likely to be significant in future UK flood defence procurement policy. The contract started on 1 June 2000 and runs for 25 years. Total contract value is £30m and the capital value of the main phase of works is £3.6m.

The Pevensey Bay Sea Defences consists, essentially, of a shingle bank 8km long between Eastbourne and Bexhill in East Sussex. Immediately inland there is an area of some 50km 2which includes over 10,000 properties, several caravan parks, road and rail links in addition to an ecologically very sensitive and important area which would be flooded if the defences were breached.

As part of a strategic study for the area, the UK Environment Agency identified a preferred option for the long-term management of the defences.

The principal component of the preferred option was to increase the shingle bank to provide a 1 in 300 year standard of protection against breach flooding.

The service to be provided is the prevention of flooding and erosion, so, in essence, PCDL is being paid for something not to happen. Moreover, flooding may not occur even if PCDL did very little or nothing.

Specific aspects of risk allocation and transfer in relation to weather event performance criteria were unique concepts to grasp. Storm events as well as the effects of sea level rise and climate change had to be incorporated into the scheme.

Weather events are a difficult issue to deal with contractually and led to complicated negotiations.

In the event of flooding occurring, very significant deductions in payments to PCDL will be made.

Activities to achieve a sustainable service delivery include ongoing annual maintenance. This includes shingle replenishment to replace material lost from the frontage.

Westminster Dredging's trailing suction hopper dredger Sospan Dau has been specifically adapted for ongoing use at Pevensey Bay, with a shallow draft and modified rainbow discharge enabling shingle won at specified offshore areas to be sprayed onto the beach.

Replenishment is complemented by re-profiling to maintain the required cross section during storm events and recycling of materials to reduce losses due to natural ongoing longshore drift, thus making best use of existing assets. PCDL will provide emergency response in storm events which will reduce the potential consequences.

Capital improvement works to be undertaken two years into the project are underway this month, with the Sospan Dau working to increase the standard of protection in accordance with the specified requirements.

The work will consist primarily of increasing the volume of shingle by 200,000m 3, therefore increasing the width of the shingle bank significantly.

A second capital improvement campaign will commence approximately seven years into the project.

MJ Information No: 17144