Case Study of Coastal Erosion and Coastal Defence:
The Holderness Coast, NE Yorkshire Coast
Where is the Holderness Coast? What is the problem?
Why is Cliff Erosion such a problem here?
1. The cliffs are made up of soft glacial material (Boulder Clay - made up of sands and gravels). This is easily eroded by the waves and the cliffs are easily undermined.
2. The Holderness Coast is very exposed, approaching waves have a long fetch over the North Sea.
3. The waves are mainly destructive - eroding the base of the cliffs (hydraulic action etc.)
4. Most of the Material eroded from the cliffs is washed out to sea, the rest is moved by longshore drift - the beaches are therefore narrow and do little to protect the coastline. (If the beaches were wider, the waves would break on the beaches reducing their erosive power).
5. The coastline is threatened further by sea-level rise.
Attempts at Coastal Management along the Holderness Coast include:
Due to extensive costs - only the most valuable areas of land are protected. Much of the area is farmland which is not protected.
Example of the impacts of Coastal Management: Mappleton
The village of Mappleton is greatly underthreat by coastal erosion along the coastline and by 1998, the main road running through the village was only 500m from the cliff top and in places it is now only 50m. The village is under threat due to the easily eroded boulder clay (glacial till) which makes up the cliff line. The area suffers from erosion rates of up to 2m per year.
To reduce the amount of erosion threatening Mappleton, 2 rock groynes were constructed in 1991 to encourage the build up of beach in front of Mappleton by trapping longshore drift. This meant that that waves would break on the beach rather than attacking the cliffs.
Problems for further down coast
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