Human Intervention

Because so many coastal areas around the world are heavily populated, allowing erosion and/or deposition to take place is sometimes not a desirable option. Erosion may destroy houses, farmland or even settlements. The coastlines of Yorkshire (south of Flamborough Head), Norfolk and Suffolk have retreated and more than 100 villages have disappeared in the past 2000 years.

Cliffs at Flanborough Head, Yorkshire

Human Intervention

Because coastal erosion is just part of a cycle of events, preventing destruction of a cliff in one area may increase erosion elsewhere. Until the 1970s, the policy nationally was to build sea defences wherever possible, certainly to protect settlements and, if money was available, also areas of farmland. This was a policy that could not be maintained, simply because of the cost, and recent work suggests that what is known as managed retreat is allowed to take place. Here, sea defences are not maintained and, when they are breached, the sea floods land behind but builds up its own sea defences such as mudflats, marshes and beach. This policy can really only work where population levels are low and the gain of a new habitat for wildlife has to be set against the loss of possibly valuable farmland.

The cliffs at Dunwich in Suffolk. Most of this village has been lost due to coastal erosion.

Human Intervention

Deposition in the form of longshore drift delivers material to replenish beaches which are a valuable attraction at many holiday resorts. Groynes have been built on popular beaches to make sure that the sand stays. These are cheap and effective but stop almost all longshore drift and may leave areas further along the coast unprotected by a beach, speeding up the erosion there. Longshore drift may also block navigation channels and many ports, especially along the east coast of Scotland and England, need to have the entrances regularly dredged to keep them clear.

Groynes stop or slow down longshore drift. These groynes were built at Hunstanton in Norfolk to prevent the beach being lost.