Jurassic coast + Swanage bay
Geomorphic processes
Landforms
Human activity
Crack-cave-arch-stack-stump cycle
Example of an arch is Durdle Door
Spit/barrier beach/tombolo
Hydraulic action
Wave pounding
Abrasion
Falls
Slump
Slide
Weathering
Chemical - chalk has high calcium carbonate, reacts with acid rain and dissolves
Example of a barrier beach + tombolo is Chesil Beach
Bays/headlands
Example of a stack is Old Harry
Hydraulic action + abrasion opens joints (natural vertical lines of weakness in a cliff) into cracks, and further into caves, and further into arches
Arch falls under its own weight, forming a stack
Stack gets eroded over time forming a stump
Waves approach the shore at an angle due to prevailing winds. This causes longshore drift, a process that transports material up the beach at an angle in the swash, and then back down the slope of the beach in the backwash. Overall, sediment is moved downwind
When the coastline turns/bends, the longshore drift carries on into the sea and keeps depositing material there until a spit is formed
If a spit connects land with an island, it is called a tombolo
If a spit crosses a bay, it is called a barrier beach
In discordant coastlines, certain points of weaker rock are eroded faster than stronger rock parts
Eroded areas form bays, and non-eroded areas form headlands
An example of a bay is Swanage Bay (soft clay)
An example of a headland is Durlston Head (harder limestone)
Salt crystallisation
Hard engineering - fighting against the problem, human made solution
Soft engineering - adapting to it, using natural processes, working in harmony with nature
Managed retreat
Sea wall
Groynes
Rock armour
Big boulders piled up on the beach
Absorbs energy of wave impact
Allows beaches to build up
Durable but expensive to set up
Wall along the coastline
Wooden barriers built at right angles to the beach
Prevents erosion, absorbs energy of wave impact and reflects it back into the sea, can prevent flooding
Expensive to set up, expensive to maintain as the wall itself begins to erode
Prevents longshore drift from dragging away beaches
Can be seen as unsightly
Costly to build and maintain (wood decomposes)
Can stop beaches from forming/removes beaches downstream as no sediment is moved along
Beach replenishment
Pump/dump sand from elsewhere onto a beach to replenish/expand it or create a new beach
Do nothing, allow everything to happen naturally
Easy and cheap/free as nothing is being done
People can lose land
Tourist attraction
Natural erosion defence
Inexpensive but requires constant maintenance - beaches can be quickly washed away
Dredging can leave holes which sediment from other beaches can flow into, depleting them