Abrasion
- A wave hitting a cliff.
- Waves have materials such as pebbles or shingle.
- Similar to abrasion in rivers.
Corrosion/Solution
- Happens on limestone and chalk.
- Calcium Carbonate in the rocks dissolves in the water.
Hydraulic Action
- Waves hit against a cliff face.
- Air trapped under cracks in cliff is under pressure.
- When the wave goes back the pressure is released.
- This causes great impact in storms.
Longshore Drift
The transportation of sediment along the beach by prevailing wind.
Deposition
Process in which sediment is laid down in new locations.
Bay
An indentation of a shoreline larger than a cove but smaller than a gulf.
Headland
A narrow area of rock sticking out into the sea. Rocks in the headland are harder than rocks behind the beach.
Arch
Erosion causing caves to appear on both sides of a headland which eventually join together. After time top of the arch will collapse only leaving a stack.
Cave
Erosion exploiting weaknesses in the headland. After time caves will appear on both sides of the headland and it will create an arch.
Stack
What comes when the top of an arch caves in and leaves the strongest part of the rock behind. After time it will eventually erode down to a stump.
Stump
What comes after a stack has been worn down after time.
Wave Cut Platform
A rocky platform left behind as cliff retreats (by Hydraulic Action, Solution, Attrition) exposed at low tide.
Offshore Bars
In the foreshore of the beach where the heaviest material is deposited. Either made of coarse sand or shingle. The offshore gradient is shallow.
Beach
Accumulation of material deposited between low spring tides and the highest point reached by storm waves at high spring tides. It has three zones- backshore, foreshore, offshore.
Spit (Sand Spit)
A beach of sand or shingle linked to land found at indented coastlines or river mouths. Become curved when wave refraction happens.
Tombolo
Ridges that link the mainland to an island.
Backwash
Water returning to the ocean from waves washing onto a beach.
Constructive Waves
A low height, low frequency wave that has a strong swash and a weak backwash. Its action is to deposit.
Destructive Waves
A high height, high frequency wave that has a weak swash and a strong backwash. Its action is to erode.
Fetch
The distance that the wind has traveled across open water.
Swash
The movement of water up the beach after a wave breaks.
Wave Refraction
When two main changes occur in the wave.
A) The speed of the wave.
B) The shape of the wave.
If it is fully completed, the waves will beak parallel to the shore.
Attrition
When eroded material (e.g. brocken rocks) hit against a cliff face.
Joint
A crack in a cliff face that shows the first stage of erosion. After time it will become a cave.
Bay/Headlands
Bays have weaker rocks, and headlands have stronger rocks. Wave refraction in bays disperses energy around the bay and focuses wave energy on the flanks of the headlands.
Berm/Shingle
Coarse material pushed up by the beach by tides and aided by storm waves throwing material above the level of the waves.
Storm Beaches
A beach consisting of material from berms or shingle ridges.
Cusps
What causes the seaweed at the edge of a berm to be irregular and scalloped.
Sounds
A lagoon developed the offshore bar and the shore. When the water is calm and fed by rivers you can find marshes and mudflats.
Recurves
When a spit is curved and it has smaller, hooks called recurves.
Sea Walls (Vertical and curved)
- Massive structure, made of concrete. Used to reflect rather than prevent waves.
- Good for protecting valuable property, holding the sea back.
- Bad for being costly, the foundations can be corroded.
Revetment
- Massive, made of rocks or concrete, absorb waves. Are porous, or act as baffles.
- Good for dissipating wave energy, cheap, reduces wave refraction.
- Bad because it doesn't cope well with strong storm waves.
Wooden Groyne
- Barrier of resistant timber piles driven into beach. Hold beach material threatened by long shore drift.
- Good because it is cheap, conserves beach by delaying export of material.
- Bad because it doesn't last long.
Gabion
- Small rocks held in wire cages.
- Good because it is less cheap and flexible.
- Bad because it doesn't last long and it is lightweight.
Rip Rap (Rock armor)
- Large rocks at foot of sea walls or cliffs, to absorb waves.
- Good because it dissipates wave energy, relatively cheap.
- Bad because rocks rocks move in storm conditions.
Off shore breakwater
- Concrete 'island' overtopped at high tide. Reduces power of waves offshore.
- Good because it can be built from waste material, mimics reef to slow longshore drift.
- Bad because it may possibly impact sea.
Beach Nourishment
- Sand pumped in from sea bed, or pebbles imported to replace lost beach material.
- Good because it is a natural process, builds up beach to provide flexible buffer, feeds material alongshore.
- Bad because it is very expensive.
Natural Beach (Do nothing)
- Accept that there is no economically viable or technically feasible solution.
- Good because it is not costly, it provides new material for beach system, it allows chance to research.
- Bad because it is unpopular with politics.
Managed Retreat
- New building and defenses are prevented. Incentives given through grants.
- Good because it is cost effective and preserves the coastline.
- Bad because people don't like to do it.
Coral Reef
- Diverse ecosystem.
- Limestone skeleton/Calcium carbonate structure.
- Created beneath the sea.
Fringing Reef
- Fringe around the flanks of volcanic islands.
- Protected by Barrier reefs.
- e.g. Moorea Island, French Polynesia.
Barrier Reef
- Grow at greater distances from the shoreline.
- Separated from land by a lagoon.
- Broader, older, and greater than other reefs.
- e.g. Great Barrier Reef, Australia.
Atoll Reef
- Rise from submerged volcanoes.
- Form rings of reefs surrounding an island until the island sinks and is replaced by a lagoon.
- e.g. Lighthouse Atoll, Belize.
Coastal Dunes
- Formed by the wind blowing sand into low lying vegetation. This blocks the sand from being transported. 'Clogs sand.'
- Foredunes are important because they provide a 'buffer zone' for dune vegetation.