Exam Question – Referring to a stretch of coast, explain the factors that have led to this coast suffering from erosion (10 marks)
Many factors have led to erosion on the Holderness coast, in North East England. These may have been processes that have been taking a while, or something that occurs suddenly. There are three main reasons for the rapidly eroding coastline at Holderness; the geology, the fetch and longshore drift and beach material.
The Holderness Coast is mainly two rock types; chalk and boulder clay. Chalk is fairly resistant and at places like Flamborough Head, it produces features such as cliffs, caves, arches and stacks. Boulder Clay is fairly weak and soft; but it is very good and fertile for arable farming. Boulder clay, also known as glacial till, is a mixture of clay and sands, which have been left from glaciers.
Holderness is exposed to wind and waves from the north-east, which have a small fetch of about 500-800 km across the North Sea. This is not far, compared to some of the world’s large oceans, but the size of the waves attacking the coast is increased by four other factors. One is the currents or swell, which circulate around the UK from the Atlantic and into the North Sea. The Atlantic fetch is 5000 km or more, and its currents add energy to waves in the North Sea. Therefore, there are often powerful destructive waves along the coastline, eroding the cliffs. The second point is the low pressure weather systems passing over the North Sea are often intense, and locally produce very strong winds and waves. Thirdly; small, almost enclosed seas, like the Mediterranean or North Sea, often generate huge waves during storms. Waves move within the sea but cannot disperse their energy – rather like water slopping up against the side of a washbasin. Lastly the sea floor is deep along the coast. Therefore, the waves reach the cliffs without first being weakened by friction with shallow beaches. As a result of these four factors, waves along...