coasts

• local factors effecting flood risk; land height, degree of subsidence and vegetation removal.
• human factors affecting coastal recession: coastal defences and offshore dredging.
• physical factors affecting rapid coastal recession: marine processes, geology and subaerial processes
• beach nourishment; + beach looks natural -has to be frequently replaced
• cliff regrading:+ natural looking slope - cliff drainage may also be required
• cliff drainage: + reduces risk of mass movement - doesn't prevent it
• dune stabilisation: + provides a natural ecosystem - can be undone by powerful storms
• groynes:+maintains size of beach - expensive £100 per metre
• sea walls:+ very effective - very expensive £5000 per metre
• riprap: +long lasting and flexible - may look unsightly
• revetments- + absorbs wave energy and traps sediment - needs constant maintenece
• offshore breakwaters: + allows long shore drift to continue - may create increased deposition
• ICZM- planning how coastal resources are used and developed. uses littoral cells as a unit for management
• SMP-they identify the risks associated with coastal processes
• Bangladesh(sea level rise and flooding)- low lying river delta. good flood warning systems. improved aid response. improved storm defences. 1970 storm killed 500,000. intense rainfall from tropical cyclones.
• Kiribati (sea level rise and flooding)- frequent natural disasters e.g. storm surges. beach eroded away quickly. fresh water was contaminated by saltwater. low lying land.
• the Maldives (sea level rise and flooding)-highest part 2.3m above sea. vulnerable to storm surges. less income= less tourists. spread out across 1200 islands. population of 340,000. 77% of Maldives will be submerged.
• delterwerken( sea level rise and flooding)- 2000 year coastal flood. storm surges. dams built to protect the land and stop the region from flooding. farmland damaged in 1953.
• the nile delta (coastal recession) low lying delta. erosion rates at some points increased 10x. recession increased since the construction of the Aswan dam 1964.
• North Sea 2013- 20,000 homes flooded. reached 6.3m in places. 18,000 people evacuated. killed 307 people in England and 2100 in the Netherlands. sea level rose 5.6m, 65000 hectares of farmland flooded.
• Happisburgh (coastal policy conflicts) house value are very love therefore residents are unable to move. beach side houses were demolished. no active intervention. had a £3 million grant
• eustatic change- change in sea level due to changes in water mass. glabal
• isostatic change- change in sea level due to the movement of land. local
• emergent coastlines- raised beach: former beach now above high tideline. fossil cliffs: cliffs formed from fossilized shells.
• submergent coastlines- ria: flooded river valley. fjord: flooded glaciated valley. Dalmatian- coastline is formed by the convergence of two continental plates.
• talus screeslopes- rock falls to the base of the slope
• rotational slumping- section of cliff remains intact as it moves down the cliff.
• long shore drift- waves approach beach at a 30 degree angle. the predominant wind direction determines the direction
• sediment cell- erosion in one place is balanced by deposition in another. sources- erosion, sediment transported by river. transfers- waves, LSD, tides, currents , wind. sinks- depositional featured of back, fore, near and off shore
• attrition- waves move rocks and corners are knocked away
• abrasion- pick up pebbles and throw them against the rock
• solution- water reacts with rock minerals and dissolve them
• hydraulic action- air compressed in crack sudden release of pressure can shatter the rocks
• sand dunes- embryo, fore, yellow, grey
• littoral zone- off, near, fore, back. zone of dynamic equilibrium causing rapid change
• tombolo- narrow low ridge
• cuspate foreland- triangular headland. develops from LSD in 2 opposite directions