UK Evolving Physical Landscape WAVES Cliffs UK Evolving Physical Landscape As a wave reaches the beach: Cliffs are produced through the process of hydraulic action and and Coasts The water running up the beach is called the swash. As the wave loses abrasion, where destructive waves erode the cliff between the high and energy, the water begins to run back down the beach to the sea, and is Memory Organiser low tide marks to create a wave cut notch. As this notch is eroded, the called the backwash. Human impact on the UK physical landscape‐DARTMOOR, cliff above becomes unstable, collapses and is removed by waves. Two types of waves! Devon Wave Cut Platform Human Evidence on the landscape Destructive Waves: Strong winds, powerful Activity waves and cause coastal erosion. They are Below the wave cut notch, an • Clearance of woodland to allow grazing tall and steep. The backwash is stronger area of exposed rock is left, which is visible during low Agricult • Dry stone walls called ‘reaves’ were made to divide up than the swash, so material is carried out tide. The surface is not ure – the land for farming purposes. Remains still present to sea. Tees‐Exe Line smooth, as erosional Farming today. Constructive Waves: Light winds, not processes such as abrasion, Settlem • Circular stone hut remains from the Bronze Age, 3,000 powerful and cause deposition, rather and weathering, continue to ents years ago found scattered across the moorland than erosion. Stronger swash, so material erode the rock face. • Dry river beds in the landscape are a result of tin is carried up the beach and deposited. Erosion of a headland Mining streaming which was very common. This consisted of altering river/stream paths which then eroded into the Discordant Coastline: landscape Bands of differing rock run perpendicular to the Uplands and Lowlands Coasts coastline. In the north and west of the UK the rock types Along this coastline, a (geology) are more resistant igneous and metamorphic mixture of clay (less Erosion is aterm used to describe a wave removing rock such as granite. This creates upland areas such as resistant), chalk and Erosion material from the coastline mountains and moorland which have a limestone (resistant) run perpendicular to the mountainous/hilly topography. Upland areas are Attrition usually colder than lowland areas because of exposure coastline. to wind as well as for every 100m gained in altitude Small rocks that the waves are carrying, Concordant Coastline: Bands of rock run parallel to the coastline. Along What other processes change our there is a decrease in temperature of 1 degree Celsius. collide in to one another. The rocks break this coastline, limestone (resistant rock) runs along the entire length of coastlines? up, becoming smaller and rounder. This the coast. In the south and east of the UK the rock types (geology) continues to occur until the rock becomes Sub‐aerial are less resistant sedimentary rock such as chalk or sand. So what does this have to do with headlands and bays? mudstone. This creates lowland areas which have a Headland –discordant coast flatter topography. Abrasion Water enters cracks, and in cold climates, freezes, Along a discordant coastline, the rocks Mechanical expanding by around 10%. This increased pressure Tectonic and Glacial activity shaping the Rocks that the wave is carrying are thrown of higher resistance erode at a slower (freeze thaw) weakens the cliff face. This process repeats, until landscape against the coastline. This wears away at rate to the rock of lower resistance. As a the rock is weak enough to fragment.. the coastline overtime. Although the UK is not on a major plate boundary it has result, the high resistant rocks protrude still been affected by continental drift. Continental drift Hydraulic Action out from the coastline, producing means that we have been drifting away from the headlands. Rain water contains a chemical called carbonic tropics over millions of year. This has lead to buckling acid, which when comes into contact with certain Large waves break against the cliff. The cliff Chemical and folding of the land. This is how the mountains in Ballard Point, Swanage. Discordant coast rocks such as limestone, can react and weaken the will often have faults/cracks in. The water Scotland were formed. rock as it dissolves. is forced into these faults/cracks in the cliff, Bays –Discordant coast which causes immense pressure. When this The roots of plants and trees, burrowing animals Glaciers had a big impact on the UK landscape during Biological pressure is released, it produces a force Along a discordant coastline, the rocks the last ice age approx. 10,000 years ago. Glaciers act as and nesting birds can all help to weaken the rock. that makes the crack larger. of lower resistance erode at a faster rate giant scourers which carve out the landscape as they than the rocks of higher resistance. This Mass Movement slowly move downhill under the force of gravity. This Solution results in the rock eroding back more creates distinctive ‘U‐shaped’ valleys. Unlike rivers quickly to produce bays. Constructive This term refers to the downwards movement of rocks and soil under which crate ‘V‐shaped’ valleys. Sea water has lots of different chemicals in, ways often bring sediment to form a the influence of gravity. and these can sometimes react with the beach. rock, causing the rock to dissolve. This occurs most frequently with limestone. Swanage Bay, South Coast of England –Discordant coast Longshore Drift How do humans affect the coastline? What challenges do coastal landscapes present? Can we protect our coastline? Waves approach the beach at an Over 20 million people in the UK live near to Many people choose to live near the Planners must try to find sustainable ways of managing the angle. Material is moved up the beach Settlement the coast. In the past sewage was discharged coastline in the UK due to the economic coastline, and do this using a process called Integrated Coastal at an angle (swash), returning into the sea (jobs), environmental (and social Zone Management (ICZM). perpendicular to the coast. Along the (communities) benefits it brings. Coastal south coast of the UK, the prevailing Coastal tourism is BIG business! 13% of jobs at erosion removes material from the Dawlish are in tourism. Coasts are often wind is from the South West, moving Tourism coastline, with many areas in the UK at managed for tourists, such as building groynes material from west to east. risk of this. The Holderness Coast in north‐ No Intervention to trap sediment for beaches. No investment in flood defences. east Yorkshire is a great example of this. It ‘Do Nothing’ is primarily made of boulder clay which is Beaches an extremely weak geology. Also due to Roads, railways, shipping ports and oil ‘terminal groyne syndrome’ as a result of refineries are just some of the infrastructure Maintain the existing coastline with Formed when eroded material is transported by Infrastructure management in place at Mappleton, Hold The Line found at the coast. The Esso oil refinery at defences. longshore drift and deposited by constructive settlements down‐drift have experienced Southampton sees 2000 ships dock each year. waves. increased erosion due to sediment starvation. Rising Sea Level Allow the shoreline to change Dredging the sea to construct ports can have Construction Managed Retreat naturally, but manage this process adverse effects to wildlife. Sea level in the English Channel is expected to rise by 15cm by 2030 due to global warming. A warmer climate causes and the impacts. Erosion water to expand, and ice sheets and glaciers to melt. Sea level rise and increased coastal erosion Agriculture will impact farmland . Build new defences on the seaward Advance The Line side. Could we see Spit London looking What are the advantages and disadvantages of coastal like this in the Bournemouth Beach. defences? A spit is a narrow ridge of sand or shingle, that stretches out from the future? coastline, into a gap in the coastline. A spit forms due to longshore drift. Sediment moves along the coastline until a change in coastline occurs. This Tourism, settlement and Defence Advantages Disadvantages results in material being deposited. This builds up overtime until the spit infrastructure. System extends out further into the gap. Saltmarshes begin to form being the spit due to it being enclosed. A spit may begin to curve due to wind and waves Protects base of from other directions. cliff. Made of Expensive and Southampton Port. Winter UK 2013 Storms Sea Wall resistant unattractive. concrete that Restricts access. Settlement, infrastructure In December 2013, the UK was hit by a series of low pressure deflects energy. Dawlish Warren and construction. systems, bringing heavy rainfall and extremely strong winds. Sand Spit, Devon. The south east of England was worst hit, with 7m storm High cost of Maintains a wide surges. Two people lost their lives, 1400 homes were maintenance. Can Groynes beach and flooded. Insurers estimated the damage to cost £100 million. impact other areas attracts tourists of the coastline. Bar Holderness Coastline. A bar is a ridge of sand or material that Agriculture, settlement. Material is easily Beach Looks natural, extends across a bay or river mouth, creating eroded. Needs Replenishment attracts tourists an enclosed water body. A bar forms in the constant /nourishment and is cheap. same way as a spit. Behind the bar, fresh or replenishment. slightly salty water becomes contained to form a lagoon. In the image to the right, a bar Prevents mass extends across the river mouth, with a lagoon Difficult to install Cliff movement, and is behind. and is very Stabilisation safer for people expensive.