Coastal erosion can lead to cliff collapse. This causes problems for people and the environment.
Case study – Christchurch Bay, near Bournemouth
The cliffs in Christchurch Bay which is on the south coast of England. The cliffs here are rapidly eroding at a rate of 1-2m per year.
The cliffs are collapsing and retreating rapidly because:
- Marine processes: the bases of the cliffs are being eroded by hydraulic action and abrasion.
- Sub-aerial processes: weathering is weakening the rock and then mass movement (slumping and rock fall) is leading to cliff collapse and further erosion.
- Geology: in Christchurch Bay permeable sand lies on top of impermeable clay. During wet weather heavy rain saturates the permeable sand, making it much heavier and making the top of the cliff unstable.
- Fetch: south-west winds, which have blown 3000 miles across the Atlantic Ocean create strong destructive waves which have lots of energy to erode.
- Human activity: it’s a tourist honeypot and there has been extensive building along the cliff top. The extra weight weakens the top of the cliff making it more unstable.
What impacts does cliff collapse have?
Social Economic Environmental
- People lose their homes if they fall into the sea.
- Homes close to the cliffs go down in value.
- It is difficult and expensive to insure houses close to the cliffs.
- It is dangerous for people to walk along the cliff tops and on the beach if the cliffs are likely to collapse.
- Roads and railways near the coast are under threat from collapse.
- Tourists may not visit the area because of the danger. This affects local businesses such as cafes, hotels, shops and taxis.
- Barton Golf Course has had to expand inland as some of its land has been lost to coastal erosion.
- Cliff collapse makes the area look unattractive.
- The cliffs near Naith Holiday Village at New Milton are being eroded but they’ve not been protected as they’re classed as a SSSI (site of special scientific interest).
- Cliff collapse exposes different types of rocks and fossils.
- Bird-nesting sites and green land at the top of the cliffs are being lost.
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