CHAPTER 10: COASTAL PROCESSES, PATTERNS AND LANDFORMS 19 09 T 10 11 18
Fig. 42 Map of Rosslare Strand to show groynes built along a sand spit
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Fig. 43 Rock armour and groynes protect this beach. Groynes are very effective methods for widening a beach and protecting the coast. Similar groynes are planned for Courtown Beach, County Wexford. Look at the photo of Rosslare strand. Can you work out the direction in which longshore drift is carrying the sand?
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The east coast of Britain has some of the highest erosion rates in the world. Losses of up to 25 m a year have been recorded. Hundreds of villages have disappeared into the sea since Roman times.
North Bull Island, County Dublin
The North Bull Island is a good example of how humans have changed the natural processes of coastal transportation and deposition in Dublin Bay. The North Bull Island is a low-lying, dune-covered sand spit running parallel to the coast between Clontarf and Sutton in the northern half of Dublin Bay. The word ‘bull’ is adapted from the word ‘ball’ which in the eighteenth century meant ‘sandbank’.
How have human activities affected natural coastal processes at the Bull Island? The island is approximately 200 years old and was formed as a result of the building of the North Bull Wall by Captain Bligh. At one time, the natural process of longshore drift carried sand and silt southwards across Dublin Bay and often blocked the port. Ships frequently ran aground on the sand banks deposited in the area.