Coasts Revision

What are the four processes of coastal erosion?

Hydraulic action, abrasion, attrition, and solution.

What is hydraulic action?

The force of waves hitting against a cliff, compressing air into cracks, leading to the eventual breaking apart from the rock.

What is abrasion?

When waves pick up sediment like sand and pebbles, which then scrape and wear away the cliffs.

What is attrition?

The process where rocks and pebbles collide with each other, breaking into smaller, smoother pieces.

What is a solution?

The process by which certain types of rocks, like limestone, are dissolved by acids in seawater.

What are the four types of coastal transportation?

Traction, saltation, suspension, and solution.

What is longshore drift?

The movement of sediment along the coast by wave action. Sediment moves in a zigzag pattern due to swash and backwash.

What is deposition?

When waves lose energy and drop the sediment they are carrying, often forming features like beaches and spits.

What factors affect the rate of coastal erosion?

Rock type, strength of waves, coastal defences, and climate (e.g., storm frequency).

What is mass movement?

The downhill movement of material under the influence of gravity, which can occur as landslides, slumping, or rockfalls.

How does rock type influence coastal landforms?

Hard rocks (e.g., granite) form steep cliffs and headlands, while soft rocks (e.g., clay) erode faster, forming bays and gentle slopes.

What is a concordant coastline?

A coastline where the layers of rock run parallel to the coast, often leading to fewer bays and headlands.

What is a discordant coastline?

A coastline where the layers of rock are perpendicular to the coast, leading to the formation of headlands and bays.

How does geological structure affect coastal landscapes?

The angle of rock strata (e.g., horizontal, dipping) can determine how cliffs erode and whether features like caves and arches form.

What is differential erosion?

The process where softer rocks erode faster than harder rocks, creating headlands and bays.

What are beaches?

Accumulations of sand or pebbles deposited by waves along the coast.

What is a spit?

A narrow piece of land that projects out into the sea, formed by longshore drift depositing sediment.

What is a bar?

A ridge of sand or shingle that forms across the entrance to a bay, often creating a lagoon behind it.

What is a tombolo?

A ridge of sand or shingle joining the mainland to an island, formed by wave refraction and deposition.

How are sand dunes formed?

Sand is transported by the wind and accumulates around obstacles, creating dunes that grow as more sand is deposited.

What are mudflats and salt marshes?

Flat, silty areas formed in sheltered coastal areas where deposition occurs, often developing into salt marshes as vegetation grows.

What are the aims of coastal management?

To protect the coastline from erosion and flooding, and to manage the impact of human activity on coastal environments.

What are hard engineering strategies?

Man-made structures built to control the sea and reduce erosion, such as sea walls, groynes, rock armour, and gabions.

What are the advantages and disadvantages of sea walls?

Advantages: Protects the base of cliffs and prevents erosion.

Disadvantages: Expensive to build and maintain, can reflect waves, increasing erosion elsewhere.

What are groynes, and how do they work?

Wooden or stone barriers built at right angles to the coast to trap sand, reducing longshore drift and building up beaches.

What is rock armour (rip rap)?

Large boulders placed at the base of cliffs to absorb wave energy and reduce erosion.

What are gabions?

Wire cages filled with rocks, placed at vulnerable areas to absorb wave energy and reduce erosion.

What is soft engineering?

A sustainable approach that works with natural processes to protect the coast, such as beach nourishment and dune regeneration.

What is beach nourishment?

The process of adding sand or shingle to a beach to make it wider, absorbing wave energy and protecting the coast.

What is dune regeneration?

The planting of vegetation on sand dunes to stabilize them and reduce erosion.

What is managed retreat?

Allowing low-value coastal areas to flood and erode naturally, creating new habitats like salt marshes while reducing pressure on other areas.

How do coastal management schemes affect the environment?

While they protect human activities, some methods (like hard engineering) can disrupt ecosystems, alter sediment flows, and impact wildlife habitats.

What is Integrated Coastal Zone Management (ICZM)?

A holistic approach that considers all stakeholders in coastal areas and aims for sustainable management by balancing environmental, social, and economic factors.