4. Types of wave weak swash and strong backwash (beach is scoured and degraded as the strong backwash pulls sand and shingle back down the beach) strong swash and weak backwash (material is moved up the beach by the strong swash) lots of energy less energy steep gentle angle large in height small in height Destructive Wave Constructive Wave
5. Coastal Erosion Abrasion (corrasion) - when the sea throws rock up to hit the cliff, and break. Hydraulic Pressure - this is where erosion occurs due to the pressures exerted by breaking waves as air trapped in cracks in the cliff is compressed by the water. This compression and sudden release gradually forces the cracks apart. Solution (corrosion) - this is where salt water can act to dissolve some chemicals in the rocks, for example in limestone, calcium carbonate is dissolved, weakening the rock. Attrition - when the sea carries the rock to hit other rocks, making the rock break into small pieces.
10. Types of transportation There are four possible types of transport within the water: Solution - material carried dissolved in the water . Suspension - fine material carried suspended within the water itself Saltation - material which is too heavy to be continuously held in suspension is bounced along the sea bed. Traction - the heaviest material is simply rolled along the sea bed.
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12. Coastal Deposition Features: Beaches Beaches are the main features of coastal deposition. A beach is defined as the gently sloping area of land between the high and low water marks .
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14. Coastal Deposition Features: Bars What are bars and how are they created? A bar is formed where a spit continues to grow across a bay, creating a lagoon behind it . The lagoon, becomes an area of still water and a salt marsh forms in this low energy zone . Over time the lagoon will become infilled by deposition as either rivers flows in to it depositing material, or as waves break over the top of the Bar depositing coastal material
15. Coastal Deposition Features: Tombolo What are tombolo's and how are they created? Tombolo's are ridges of sand and shingle which join the mainland to an island . Tombolo's are created through the process of longshore drift . Where there is a change in the shape of the land, a spit forms in the shallow / sheltered water . A tombolo is formed where the spit continues to grow until it reaches an island, forming a link with the mainland .
16. Coastal Management Rapid coastal erosion often poses a threat to the settlement, industry and recreation that has grown up along the coast and we often look to protect the coast from erosion through appropriate management of the coastal system .
1 . Headlands and Bays form along coastlines where rocks outcrop at 90 o to the coast 2 . Here there are alternate bands of resistant and less resistant rock 3. Where there is soft rock (e.g. clay), erosion is rapid - and bays are formed (indent in coastline) 4. Where there is more resistant rock (e.g. chalk), erosion is much slower - headlands are formed as the harder rock is left sticking out into the sea 5. Exposed headlands then become vulnerable to destructive waves but help to shelter neighbouring bays.
1 . Wave erosion is greatest where waves break at the base of a cliff . 2 . A wave-cut notch is formed at the base of a cliff due to undercutting by wave erosion ( e . g . abrasion / hydraulic action ) 3 . As undercutting continues, the cliff will eventually collapse and retreat . 4 . The gentle sloping rocky platform left behind when the cliff retreats is called a wave-cut platform . This feature is only exposed at low - tide .
The sea attacks the foot of the cliff ( through processes of erosion such as abrasion and hydraulic action ) , eroding areas of weakness ( e . g . joints - cracks in the rock ) 2 . These cracks get larger developing into small caves 3. Further erosion widens and deepens the cave until it is eroded through the headland forming an arch (this process may occur quicker where two caves erode back to back along the same line of weakness) 4. Undercutting of the arch occurs and the roof of the arch is weakened by weathering, eventually collapsing leaving a stack (column of rock isolated from the headland) 5. The stack continues to be eroded and eventually collapses forming a stump (covered at high tide).
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