Coastal Systems and Landscapes from notes Flashcards
What type of system is the coast?
An open system
What are the inputs into the coast?
Wind Waves Sediment Sea levels tide currents
What are the outputs of the coast?
Energy
Taking away of sediment
What are the stores of a coast?
Beach rocks stumps stakes bay coves spits, bars features of erosion features of deposition
The dynamic Equilibrium in coastal systems is affected by?
- The supply of sand
- The energy of the waves
- Changes in sea level
- Location of the shoreline
What are the 4 parts of a beach?
Offshore
Nearshore
Foreshore
Backshore
Label a wave
crest
trough
wavelength
wave height
What are the 4 sources of energy?
Waves
winds
Tides
sea currents
Why does a wave break?
As waves a[[roach shallow water, friction with the seabed increases and the base of the wave begins to slow down. This has the effect of increasing the height and steepness of the wave until the upper port plunges forward and the wave breaks.
What ratio does a wave need to break?
(1:7)
What affects the amount of energy a wave has?
Fetch
duration of wind
direction of wind
What are the 2 types of wave?
Constructive
Destructive
What characteristics do destructive waves have?
Stronger backwash weaker swash higher wave height higher frequency shorter wavelength 14/min high energy steeper beaches plunging
What characteristics do constructive waves have?
Weaker backwash weaker swash smaller wave height lower frequency 6-8/min long wavelength low energy spilling gentle beaches
What is a spring tides?
Takes place when the earth sun and moon are inline
happens on day 14 and 28
What is a neap tide?
Happens on day 7 and 21
a lower tide when the moon is at a 90 decree angle to the sun.
Tides vary due to:
The morphology of the sea bed- affects the speed of travel
proximity of land masses- shore, headlands ect.
coriolis force
What are the stages of wave refraction?
When waves approach the coastline they begin to refract
waves in shallow water slow down due to friction with
the sea bed
Waves become parallel to coastline
The part of the wave in deeper water moves forward faster causing the waves to bend.
Therefore energy is on the headland causing eurotion. the rest of the wave has less energy therefore de[ostion takes place
What are the different ocean currents?
- Longshore currents
- Rip currents
- Upwelling
Longshore currents-
Longshore drift, causing a flow of water parallel to the coast
Rip currents-
Move away from the coastline, may start parallel and then where there is a headland head out to sea.
Fastest 8ft/second
Upwelling
wind blow away surface (warming) water allowing cold water, which full of nutrients, makes its way up to the surface.
What are the processes of erosion?
Attrition solution Abrasion Hydraulic action Quarrying
Attrition-
Material being carried by the sea hit against each other becoming smaller, rounder and smoother