coastal systems and landscapes Flashcards
shoreline management plans (SMPs)
integrated systems of coastal management introduced into the UK in 1995- there are 22 SMPs in England and Wales covering all the coastline and matching sediment cells areas
integrated coastal zone management (ICZM)
coordinated application of different policies affecting the coastal zone e.g nature protection, fisheries, industry, energy production, shipping, tourism- sustainable development via a cycle of planning, decision- making, managing and monitoring implementation, information collection
positive feedback loop
enhancement or amplification of changes; tends to move a system away from its equilibrium state and make it more unstable
negative feedback loop
dampening or buffer of changes; tends to hold a system to some equilibrium state making it more stable
dynamic equilibrium
state of balance between changing inputs and outputs over time
fetch
distance of open water over which a wind blows uninterrupted by major land obstacles- length of fetch helps determine magnitude and energy of waves
landscape
stretch of coast where related landforms combine to form a coastline with specific characteristics
constructive waves
waves with low height & frequency (6-8 per min) but long wavelength- swash more powerful than backwash so beach material increases (accretion)
destructive waves
waves with high height and frequency (10-14 per min) but steep form- backwash stronger than swash so beach material removed/ eroded
sea currents
seasonal directed movement of sea water generated by forces such as wind and the coriolis effect
neap tide
twice daily (in UK) rise and fall of the level of the sea in response to gravitational pull of the sun and moon, neap tide is lowest tidal range/ difference between high and low tide
low energy coast
coastline where wave energy is low and the rate of deposition characteristically exceeds the rate of erosion
high energy coast
coastline where strong, steady prevailing winds create high energy waves and so the rate of erosion is greater than the rae of deposition
sediment cells
distinct area of coastline separated from other areas by well-defined boundaries that hold in sediment pathways such as headlands and stretches of deep water
sediment budget
balance between sediment being added to the coast and being removed from the coast along a sediment cell stretch of coast
sub-aerial weathering
disintegration of rocks on cliff faces ‘in situ’- could be mechanical through temperature change, biological or chemical through reactions
erosion
wearing away of the surface by the mechanical movement and actions of agents or erosion e.g wind, rivers, marine waves, glaciers
mass movement
movement of material downhill under the influence of gravity- may be assisted by rainfall lubrication
hydraulic action
power of the impact of water directly onto rocks
wave quarrying/ cavitation
breaking waves trap air as they hit cliff faces and this is compressed into gaps in the rockface exerting pressure and then the pull back of water allows an explosive effect as the air pressure is released so this weakens cliff faces
wave refraction
when waves approach an irregular coast they are refracted so that energy is concentrated on headlands (more erosional) and spread out into bays (reducing velocity to deposit more)
corrasion/ abrasion
sand, shingle and boulders picked up by the sea are hurled against the coast within waves causing erosion
solution/ corrosion
dissolving of calcium based rocks such as limestone in areas where freshwater and seawater mix or when salt from seawater spray crystallises and expands
attrition
rocks within the sea hit each other and break angles off and so become rounded over time e.g pebbles
traction
large stones and boulders are rolled along the seabed and beach by moving seawater
longshore/ littoral drift
where waves approach the shore at an angle and swash and backwash then transport material along the coast in the direction of the prevailing winds/ waves
deposition
when sand and shingle accumulates faster than it is removed- in low energy environments and situations
runoff
stream emerging into a bay or cascading over a cliff taking large quantities of load to the coast during times of flood and high discharge
wave-cut platform
gently sloping and smooth platform of rock at the base of a cliff left behind after successive cliff collapses and cliff retreat- as it grows in size it absorbs more wave energy
cliff profile
height and angle of a cliff face, plus its features such as wave cut notches and changes in slope angle from base to top
arch
a hole in a headland caused by the meeting of sea caves as they erode backward into headland rocks
stack
isolated portions of rock left behind after an arch collapses
spit
an elongated, narrow ridge of land that has one end joined to mainland and the other projecting out into the sea or across an estuary- composed of sand and shingle
tombolo
spit that joins an island to the mainland e.g chesil beach in the uk
offshore bar
ridge of material that remains semi-submerged and accumulating material seaward side of the breaker zone
barrier beach and island
elongated bank of deposited sand and shingle lying parallel to the coastline and not submerged by incoming tides- when the bank is high enough to allow sand dunes to develop a barrier island is formed
sand dunes
where dried out wind blown sand accumulates on beaches and spits and is stabilised by vegetation such as marram grass
estuarine
partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it and with a free connection to the open sea- a transition zone between river environments and marine environments
mudflat/saltmarsh
low lying muddy area of the shore in a sheltered shoreline that is exposed at low tide and submerged at high tide and composed of silt and clay- can become a saltmarsh overtime with specific ecosystem
halophytic plants
salt tolerant plants, such as Spartina, that can colonise salt marshes
eustatic sea level change
global change in sea level resulting from an actual fall or rise in the volume of water in the sea level basins
isostatic sea level change
result of an increase or decrease in the eight of the land e.g when the height of the land increases, the sea level falls in relation to it and when the height of the land decreases the sea level rises in relation to it. isostatic change is a local sea level change not global
tectonic sea level change
sea level change due to movement of the land in relation to it as a result of tectonic movements e.g changes to land levels along fault line
emergent coastline
a coastline that has characteristics features of sea level fall and retreat
submergent coastline
a coastline that has characteristic features of sea level rise and inundation
raised beach
areas of former wave-cut platforms and their beaches which are at a higher level than the present sea level
fjord
a former glacial valley drowned by rising sea levels
marine platforms
a large expanse of gently sloping formerly submerged land exposed by uplift or the lowering of sea levels
rias
former river valley drowned by rising sea levels
Dalmatian coast
an area where the river valleys runs parallel to the coastline and have been flooded by sea level rise so islands and peninsulas are parallel to and just offshore from the mainland
