- Created by: Rachel
- Created on: 03-06-12 12:53
- The size and energy of a wave is influenced by the wind's strength, how long it's been blowing and the fetch, which is how far the wave's travelled.
- Swash is when a wave breaks and water washes up the beach.
- Backwash is when the water then runs back down the beach.
- Abrasion is where waves bring bits of rock and sand with them and grind the cliffs down like sandpaper.
- Attrition is where waves cause rocks and pebbles onshore to smash together getting smaller and smoother.
- Solution is acids contained in sea water slowly dissolving rocks such as chalk and limestone.
- Longshore drift is when waves strike at an angle, moving material along the beach.
- Coasts are shaped by erosion, transportation and deposition.
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- One of the most common features of the coastline is a cliff. They are shaped through a combination of coastal erosion and weathering.
- Weathering weakens the top of the cliff while the sea attacks its base, forming a wave-cut notch.
- Headlands and bays are formed when the sea attacks a section of coast that has alternate bands of hard and soft rock.
- Caves are made when waves force their way into cracks in the cliff face. If the cave is in a headland, it can break through to the other side forming an arch.
- The arch will grow until it can no longer support its top. It collapses, leaving the headland on one side and a stack on the other.
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- Deposition creates spits, tombolos and beaches.
- Beaches are made of eroded material that has been transported and deposited by the sea.
- A spit is a stretch of beach material that sticks out to sea, joined to the mainland at one end.
- A tombolo is a stretch of beach material that connects an island to the mainland.
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- Techniques for managing coastal erosion fall under two categories - hard engineering and soft engineering.
- Hard engineering tends to be expensive. Solutions can be unsustainable and have a high impact on the landscape and environment.
- Soft engineering options are often cheaper. They are usually more long-term and sustainable, with less impact on the environment.
- Beach management is replacing eroded beach or cliff material. It requires constant maintenance to keep replacing the material as it is washed away.
- Managed retreat is where low value bits of coast are allowed to erode and flood naturally.
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Coastal Bangladesh flooding
Disadvantages to living in Bangladesh
- The low-lying islands are very vulnerable. They get flooded easily. It is difficult to protect them.
- There are poor communications - many locals do not own their own telephone or television. It is difficult to get flood warnings out.
How can the risk of flooding be reduced?
Bangladesh is an LEDC - it therefore does not have money to implement large schemes.
- It is always going to be threatened with flooding, so the focus is on reducing the impact.
- The Flood Action Plan is funded by the World Bank. It funds projects to monitor flood levels, and construct flood banks/artificial levees.
- More sustainable ways of reducing the flooding include building coastal flood shelters on stilts and early warning systems.
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