There are many ways to manage our coastlines against coastal erosion, sea level rise and flooding. Traditionally, hard engineering management involves using artificial structures, whereas soft engineering management is a more modern day technique which is often a more sustainable way to manage the effects of coastal erosion and flooding.
There are two contrasting approaches to coastal management.
Hold the line – this is when coastal defences are built or maintained to protect a coastline against the impacts of sea level rise and coastal erosion/flooding. Often a mixture of hard and soft engineering strategies is used. This is often expensive but popular with local residents.
Retreating the line (managed realignment) – this is when people move out of the dangerous, most vulnerable areas and there is no defence against the elements. The coastline is often eroded inland creating salt marshes. This is less expensive but not always popular with local residents.
At Happisburgh in Norfolk, eastern England, the decision was to hold the line.
Happisburgh is an example of a low-lying coastline which has been eroded away very quickly
Reasons for management
The coastline is eroding at an average of 2 metres a year. There are several reasons why the coast at Happisburgh is eroding so rapidly:
Rock type – the cliffs are made from less resistant boulder clay (made from sands and clays) which slumps when wet.
Naturally narrow beaches – these beaches give less protection to the coast as they don't reduce the power of the waves.
Man-made structures – groynes have been installed to stop longshore drift and build up the beaches in certain places. This narrows unprotected beaches elsewhere even further, as new sand does not come down to replace sand eroded by waves.
Powerful waves – waves at Happisburgh travel long distances over the North Sea (so have a long fetch) which means they will increase in energy.
Management strategies used at Happisburgh
Happisburgh is protected by a wooden groynes, wooden revetments (now badly damaged) and rock armour.
Coastal management at Happisburgh has tried to make the beach wider by using groynes, and also uses a sea wall to protect the coast.
Cost benefit analysis
There are many social and economic reasons why some coastlines such as Norfolk have been heavily protected, while others have not. Cost benefit analysis involves working out all the benefits of something and comparing with the costs (problems) that the new idea may create. In areas with many people at risk the benefits of protecting an area often outweigh the costs of doing nothing.
Social reasons – many people who live along eroding coastlines believe their safety and security must be maintained. Some people disagree with where the sea defences have been located, especially if it means the land in their community is not protected.
Economic reasons – some sea defences negatively impact tourism and reduce the amount of money coming in to the area. Sea defences are very expensive, so if the number of people living there is low (low land value) then governments and councils may choose not to protect.
Environmental reasons – managing coastlines are important to help preserve and protect wildlife and natural habitats from destruction.