Delivering Legacy from the Pevensey Bay Coastal Defence Scheme

The mixed, shingle barrier beach at Pevensey Bay, East Sussex, represents a crucial asset in flood defence and coastal risk management along the East Sussex coastline, protecting the low-lying Pevensey Levels, with designated wetlands as well as thousands of vulnerable properties (many built at the crest) and coastal infrastructure. The 9km frontage is highly dynamic and suffers a net loss of sediment due to littoral drift, partly blocked by the Sovereign Harbour breakwater at the southern side (Sutherland and Thomas, 2011). This is managed through continuous bypassing and recycling of beach material, as well as regular beach nourishment and repair of key groynes, following a major capital recharge scheme in 2002. This is operated under a unique, private finance initiative, to provide a 1:400 year standard protection against breaching and maintaining a crest elevation. The spatial and temporal variations in beach volume, erosion and rollback remain poorly understood, and interventions to redistribute beach material are continuous. Furthermore, the beach experiences lowering of the sandy foreshore, though the exact drivers for this remain unknown. The aim of the project is to develop and apply novel methods for measuring shoreface processes with an emphasis on wave energy fluxes and sediment transport across the very shallow nearshore, with arrays of bottom-mounted instruments, synoptic X-Band radar, and a sustained survey campaign carried using autonomous aerial and surface vehicles. A regional sediment budget will be constructed to inform future management of the barrier.