A Level CIE Geography: Coastal Environments

coast

narrow zone where land and sea meet and directly interact [varied and rapidly changing of al landscapes]

coasts are the most…

rapidly changing of all landscapes

four factors affecting the coastline

marine, human, atmospheric, terrestrial

two atmospheric factors affecting the coastline

• climate - wind, temperature, rainfall etc.

• climate change e.g. global warming, ice ages

three terrestrial factors affecting the coastline

• tectonic movements

• geology - rock type and rock structure

• ecosystems - sand dunes, salt marshes, mangroves

five marine factors affecting the coastline

• wave action

• longshore drift

• currents

• tides

• salinity

nine human factors affecting the coastline

• coastal settlements

• recreation and tourism

• port construction

• farming

• land reclamation

• sand and gravel extraction

• pollution - land-based and marine

• conservation

• coastal management

what are the main agents of change in coastal environments

waves

what are waves caused by

frictional drag of the wind as it blows across open water

wave direction is a reflection of

wind direction

what three factors do the size of wave and wave energy depend on

• wind speed

• length of time that wind blows in constant direction

• length of the fetch

fetch:

distance of sea over which wind can blow

which coastlines have larger fetches and which have smaller

coastlines that face large ocean e.g. west ireland = larger. coastlines around enclosed sea e.g. south france = smaller

the greater each of the three wave size factors is…

the bigger the waves

where are the biggest waves and why

southern ocean at forty and sixty s where westerly winds blow continuously, avg five m in height w/ some twice the height

where are the smallest waves and why

around equator where wind speeds are low particularly where winds fetch is limited by islands e.g. indonesia and enclosed seas e.g. mediterranean and caribbean bc reduced fetch available for wave gen.

once created, waves move in what direction

same of the wind that created them

why is it only the wave form that moves

water particles simply rotate in circular/elliptical movement as the wave passes through, it is the energy of the wave that moves towards the shore, not the water.

when does wave energy translate into the movement of water towards the shore

when a wave breaks

wave crest:

as the water in a wave rises, it forms the wave crest. top of the wave

wave trough:

as the water in a wave falls, it forms wave trough - low point between two wave crests

wave height:

difference in height between wave crest and wave trough

wave length:

distance between two wave crests. not usually evenly spaced

wave period:

time taken for a wave to travel through one wave length

wave velocity:

speed of movement of the wave crest calculated by avg wl/avg wave period

wave frequency:

no. waves that break on beach in given period of time

wave steepness:

calculated by wave height/wl. ratio cant exceed [1:7/0.14] bc at that point wave breaks

wave energy:

in deep water energy of wave is