Refurbishment and repair of the world-famous Cobb Harbour and breakwater in Lyme Regis – A case study describing the multiple social, economic and community benefits a coastal engineering project can bring, and the challenges this presents

The Cobb Harbour and breakwater is the oldest example of this type of structure in the UK with the original elements dating back to the 12th century. The structure is Grade 1 listed and displays a number of unique heritage features.

Today the Cobb provides coastal erosion protection to 60 homes and businesses within Lyme Regis, as well as being the home for an active commercial fishing fleet, a leisure vessel fleet, an aquarium and a RNLI Lifeboat station.

A recent structural survey of the Cobb found that it was suffering from serious scour and undermining in many areas as well as structural movement. It has been estimated that without intervention failure of the Cobb is likely to occur in approximately 20-30 years, leaving 60 properties exposed to coastal erosion.

West Dorset District Council commissioned a project to develop the design for repairs to the Cobb whilst also wishing to deliver commercial and recreational amenity upgrades. Given the structures listed status it was imperative that any interventions were sensitive to the historic nature of the structure, balancing the needs for improvement against heritage impact and cost.

This paper examines the improvement options that have been developed and considers the challenges faced by the team to achieve the critical balance between the desire for structural and amenity improvement and heritage acceptability. The improvements can be broadly split into the following areas; scour and wave overtopping protection, public amenity improvements and commercial amenity improvements.