Canons of Coastal Engineering in the United Kingdom: Seawalls/Groynes, a Century of Change?

摘要

A Royal Commission on Coast Erosion and Afforestation, 1911, investigated the state of coastal erosion and the resulting protection measures carried out in the U.K. This paper looks at progress undertaken with respect to seawall and groyne protection in the more than 100 years since publication of the report. Seawall design has been greatly modified, although curved and stepped designs were built in the Victorian era, as well as the more common vertical ones. Groynes have also been modified from invariably using wood and rock to other materials, e.g., metal, concrete precast elements, geotextiles, as well as shape, e.g., Y, gamma, or T shaped groynes rather than orthogonal to the beach. Numerical/physical modelling has now made both structures much more robust and rigorous, although arguments are still ongoing regarding how they are used. A strong environmental concern and the need to maintain the beach for recreation characterize most present day projects and are factors that were considered but spasmodically a century ago. These factors favoured new solutions from submerged structures to beach nourishment, which limit the leading role of the seawall/groyne structures used 100 years ago.