Geography - The Coastal Zone

Corrasion

• Fragments of rock are picked up and hurled at the cliff by the sea.
• The rocks scrape and gouge the cliff face.

Hydraulic Power

• The power of the waves as they smash into the cliff face.
• Trapped air is blasted into cracks causing the rock to break apart.

Attrition

• Rock fragments carried in the sea knock against each other in the water,
• The rocks become smaller and rounder.

Solution

• Some rocks can be dissolved by seawater.
• The main rocks that do this are, limestone and chalk.
• Limestone and chalk form many cliffs in the UK

Abrasion

• The sandpaper effect.
• Pebbles grind over a rocky platform.
• Creating a smooth platform.

Mechanical

• This is where rocks are broken down without any change in the chemical nature of the rock.
• The rocks are 'torn' apart by physical force, rather than by a chemical breakdown.
• E.g. Energy form the earth's crust or freezing.

Biological

• This is caused by living organisms.
• E.g. Digging animals, microscopic plants, algae and Fungi.

Chemical

• Takes place in almost all rock types.
• Reactions break the bond holding rocks together and they fall apart.
• Common where there is water
• E.g. Oxidation, Carbonation or Hydrolysis

• The process of moving sediment down the beach
• Prevailing winds mean the Swash carries sediment up the beach.
• The Backwash carries the sediment back down the beach.
• The waves are at an angle when they approach the beach.
• It doesn't happen at all beaches because most waves come straight on.

Hard

• Artifical structures are used to control natural processes.
• E.g. Sea Walls, Rock Armour or Groynes

Soft

• A sustainable approach, which uses natural techniques, is used to control natural processes.
• E.g. Beach nourishment, Dune regeneration, Mananged Retreat

Cliff Collapse

• A wave-cut notch occurs because of erosion then the cliff becomes unstable and collapses.

Impacts Of Coastal Erosion

• Loss of houses
• Loss of habitat for wildlife
• Job losses
• No house insurance
• Injuries
• Loss of tourism and money

Threats

• The beach is retreating up to 6m per year.
• The marsh is eroding which exposes the beach.
• More tourism is causing pollution and damage to the Marshes.
• Sea levels are rising and the low sea wall is under threat.

The Wildlife

• The Ringed Plover feeds and nests on the salt marsh.
• The Wold Spider clings to Cordgrass waiting for food.
• The Sea Lavender attracts Wildlife and is pretty.

Management Plans

• Rock Armour and beach Nourishment was introduced in 1996, and the spit has not been breached.
• The marsh is now a SSSI so access is limited and the area is being watched.

• Longshore Drift transports sediment down the coast.
• When the coast changes direction (e.g. a headland) the sediment starts to build out to sea.
• This continues until a sand barrier has bulit away from the coast.
• If the prevailing wind changes direction then the spit can get a curved end.
• A spit can turn into a bar.

Headland - resistant sections sticking out from the coast. They are more vulnerable to powerful waves creating a wave-cut notch.

Bays - weaker sections erode quicker. These are sheltered, and less powerful waves build a sandy beach.

Caves - a soft part of a rock cracks and gets eroded by Hydraulic power. This carried on until the cave gets bigger, but doesn't go all the wat through.

Arches - an arch is where a cave has been eroded all the way through on a headland.

Stacks - the top of an arch has fallen down after years of erosion as it can't be supported any more.

Stumps - a stack has been eroded so much that in shrinks in size becoming a Stump.