coastal landscapes ✓ Flashcards
what is a cliff ?
Cliffs are shaped through erosion and weathering. Soft rock erodes quickly and forms gentle sloping cliffs, whereas hard rock is more resistant and forms steep cliffs
what is the wave strength (wave speed) ?
the speed that a wave is travelling
what is the wind duration ?
the length of the time the wind has been blowing
what is fetch ?
is the distance of open water over which the wind has been blowing
what is swash ?
the movement of water and load up the beach
what is backwash ?
the movement of water and load back down the beach
what are characteristics of destructive waves ?
- are formed by strong winds that have blown over large fetch areas
- they are powerful and lead to coastal erosion
- they are tall and deep
- closely spaced and frequent
what are characteristics of constructive waves ?
- associate with light winds
- waves have less energy and encourage deposition
- they are low in height
- they are widely spaced
- break gently
what are prevailing winds ?
are the dominant wind direction in an area
what is a beach ?
- A beach is a narrow, gently sloping strip of land that lies along the edge of an ocean, lake, or river
- beaches are formed when eroded materials transported by longshore drift and deposited by constructive waves along the coastline
what is a spit ?
- a spit is a permanent landform resulting from marine deposition
- it is a long narrow accumulation of sand or swing
- with one end attached to the land and the other projecting at a narrow angle
what is a bar ?
- is a ridge or barrier of sand or shingle which stretches across a sheltered bay
- it is only able to extend across a bay die tot he absence of a river
what is coastal erosion ?
is the removal of material from the coast by wave action causing the coastline e to retreat inland
what are rising sea levels in coastal erosion ?
- have risen by 12 cm in the past 100 years
- levels are expected to rise by another 11-16 cm by 2030
- warmer climate causes sea water to expand and also causes the ice sheets and glaciers to melt
what are storm surges in coastal erosion ?
- is a large scale increase in sea level
- as gale force winds drive water towards the coastline
what are groynes in coastal erosion ?
- are built to trap sand
- removing sediment from the system results in increased erosion further along the coast
what is dredging in coastal erosion ?
- it removes sand and gravel
- which causes increased erosion from the place that the sand and gravel has been taken from
how are building coastal defences in coastal erosion ?
- they are built to reduce coastal erosion
what are examples of coastal defences ?
- sea walls
- rock armour
- groynes
- beach replenishment
- marsh creation
what are the advantages and disadvantages of sea walls ?
advantages:
- prevents flooding
- protects tourist beaches
disadvantage:
- costs a lot more money
- has to be restored in a few years
what are the advantages and disadvantages of rock armour (rip rap) ?
advantage:
- can last a long time
- relatively cheap
disadvantage:
- makes access to beach difficult
- litter is trapped
what are the advantages and disadvantages of groynes ?
advantage:
- relatively cheap
- larger beaches attract more tourists
disadvantage:
- dangerous
- impede walking a long the beach
what are the advantages and disadvantages of beach replenishment ?
advantage:
- makes beaches wider
- makes beach safer
disadvantage:
- very expensive
- removing sediment from an area might effect that area
what are the advantages and disadvantages of marsh creations ?
advantage:
- takes pressure off areas in the coast
- creates intertidal habitats
disadvantage:
- costs a lot of money
- lost land
are sea walls soft or hard engineering ?
hard
is rock armour (rip rap) soft or hard engineering ?
hard
are groynes soft or hard engineering ?
hard
is beach replenishment soft or hard engineering ?
soft