Coasts Presentation

Coastal management

Key points:
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.

Erosional landforms

Key points:
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.

Coastal processes

Key points:
Waves are made by wind blowing over the surface of the sea. The power of waves is one of the most significant forces of coastal change.
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.

Depositional landforms

Key points:
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.