Coastal Systems Flashcards
Fetch
the sea distance over which the wind travels to produce waves
Swash
the landward flow of water
Backwash
the seaward flow of water down a beach
Accretion
the growth of a natural feature by enlargement
Psammosere
the succession of plants that develop on a sand dune (sea rocket, lyme grass and marram grass)
Eustatic change
sea level change that affects the globe (glacial melt)
Isostatic change
sea level change affecting localised areas
Groynes
timber or rock structures built at right angles to the coastline
Hold the line (SMP)
maintaining or upgrading level of protection
No active intervention (SMP)
‘do nothing’
Advance the line (SMP)
building new defences seaward of the existing defence line
Management realignment (SMP)
allowing retreat of the shoreline with management to control or limit movement
Gabions
hard engineering method - wire cages filled with small rocks, often used to support week cliffs
Revetments
hard engineering method - wooden barriers in a slat like form placed at the base of a cliff or top of a beach
Beach cusps
small semi circle depressions in sand and single on swash aligned beaches
Ripples
micro beach ridges parallel to the shoreline
Ridges and runnels
alternate raised and dip sections that run parallel to the shoreline, exposed at low tide
Destructive wave characteristics
short wavelengths, greater height and more frequent (10-14 per minute)
Constructive wave characteristics
longer wavelengths, lower heights and less frequent (6-8 per minute)
When does salt weathering happen?
when rocks become saturated with water
Chemical weathering processes?
Involves the decay or decomposition of rock, water acts as a dilute acid. Tends to increase with rising temperatures and humidity as carbonic and limestone react as a greater rate.
Name the 3 sub-zones of a beach with a description of each
offshore - beyond the breaking waves area
Nearshore - inter tidal and within the breaker zone
Backshore - above the influence of normal wave patterns
Tombolo
when two spits join the mainland at one end of the island together
Spits
long, narrow stretches of sand or shingle that protrude into the sea or across an estuary
Concordant coastlines
layers of hard and soft rock run parallel to the coast (depositional landforms)
Discordant coastlines
layers of hard and soft rock run perpendicular to the coastline, at 90 degrees (erosional landforms)
abrasion is:
As waves break on the shore, the water, stones and the energy of the waves cause erosion.
hydraulic action
as water is forced into small cracks by waves, pressure builds, and when the water leaves, the pressure is released. this process repeated over time weakens rock
attrition
when pebbles hit each other and become smooth over time as sharp edges are ‘knocked off’ through collisions with other pebbles
