Jurassic Coast Case Study

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Important locations on Jurassic Coast

• Chesil Beach - tombolo

• The Fleet Lagoon (behind Chesil Beach)

• Chalk headland - Old Harry stack

• Sandbanks spit

How does GEOLOGY affect geomorphic processes here?

• Made of bands of harder (chalk + limestone) and softer rock (clay) → headlands and bays

• Has both concordant + discordant coastlines

Temperature’s effects

• Warm, dry summers

• Freeze-thaw rare due to mild winters

Wind’s effects

• South west prevailing winds can bring storms from Atlantic

• High energy destructive waves can increase erosion - eroding base of cliffs

• Unstable cliffs → mass movement

Rainfall’s effects

• Relatively low annual rain (but heavy rain in winter)

• Soils can saturate in winter - slumping of cliffs

• Chemical weathering of chalk (carbonation)

Quarrying impacts

• Limestone (building material) quarried on Isle of Portland

• Quarries expose large areas of rock, making them vulnerable to chemical erosion

Tourism impacts

• Major tourist attraction

• Coastal footpaths eroded by walkers

• This exposes soil and rock to weathering and erosion by wind and rain

Swanage coastal management

• 1.8km coastal defence works - mainly stone sea walls and timber groynes

• 90,000m^3 sand deposited → dissipate wave energy

Positives of defences

Lots of hard + soft defences → holistic

Negatives of defences

• Beach nourishment needs recharging

• Groynes starved the north region of sediment → narrower beach, less dissipation of wave energy