Coastal Processes

 The depth of water around a coast varies and as a wave approaches a coast its progress is modified due to friction from the seabed, halting the motion of waves.As waves approach a coast they are refracted so that their energy is concentrated around headlands but reduced around bays. Waves then tend to approach coastline parallel to it, and their energy decreases as water depth decreases.

REFRACTION

TIDES

SPRING TIDE - when the sun and moon are in-line is when the largest tidal range is

NEAP TIDE - when the sun, earth and moon are at right angles is when the smallest tidal range is

EROSIONAL PROCESSES

Hydraulic Action - the sheer force of the wave against the cliff compresses air into cracks causing pressure to break them openSolution - sea water has a chemical reaction with some rock types causing it to dissolveAttrition - rocks hit together as they are transported causing them to break into smaller sharper piecesAbrasion - rocks carried in waves hitting against the cliff which are smashed into smaller pieces 

SUB AERIAL PROCESSES

Mass movement

Weatheringfrost shattering, biological, chemical

FACTORS EFFECTING EROSIONHuman activity - building of sea defences, walkers etc.Global warming - sea level rise leads to more energy therefore more erosionWave steepness and breaking point - the steeper the wave the more energy it has Fetch -  the greater the distance the greater the fetch and the greater the amount of wind energy is available to generate waves the larger the fetch the bigger the wavesHeadlands - waves are refracted round the headland concentrating most its energy on it Sea depth - the deeper the sea the less friction there is resulting in high energy wavesBeaches - a wide flat beach has more area for the wave to cover when it breaks reducing its energy

Refraction and Tides