1.2.1 Coast processes

• constructive waves- strong swash, weak backwash, adds material
• destructive waves- weak swash, strong backwash, removes materials
• swash - (adds) forward movement of a wave
• backwash - (takes) backwards movement of a wave
• constructive waves are lower but have a longer wave length
• destructive waves are steeper but have a shorter wave length
• prevailing wind- the direction in which wind has travelled, as coastlines in the direction of prevailing wind have been eroded quickly due to wind powering destructive waves.
• Sea attacks lines of weakness in cliff face opening the crack to erosional processes, if the crack is eroded further a cave is formed, if the cave is eroded right through the headland an arch is formed, and the arch will eventually collapse and is then eroded to form a stack, the sea stack is weathered until a stump has been formed, often covered by water at a high tide
• longshore drift- waves approachthe coast at an angle. they push the material up the beach diagonally (swash) and pull it back (backwash). over time this leads to material being deposited at the foot of the cliff
• material is moved along the coast by long shore drift, waves break on the beach and the material is carried along the beach
• the end of a spit curves due to the wind changing directions
• salt marshes are formed from a spit not letting water through
• spits form when sediment builds up at the mouth of estuary or river delta
• shingle is small stones that roll around easily
• beaches can be made of sand, shingle or pebbles
• geology affects the rate of coastal processes as soft rock can easily erode. permeable layer of rock on top of impermeable layers can lead to slumping. bands of hard/ soft rock = headlands and bays
• climate can affect the rate of coastal processes by major storm events can leas to changes such as cliff collapse or reshaping of spits
• Human activity can affect the rate of coastal processes by building coastal defenses like groynes can slow erosion in one place but increase in another