Holderness Coastline - Coastal Erosion
- Created by: Lauren_1987
- Created on: 04-05-17 09:16
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- Holderness Coastline -Coastal Environments (erosion)
- Information
- 4 km in land from where it was in Roman times
- North of England, runs between Flamborough Head & Spurn Point
- Average annual rate of erosion is 2 metres per year
- Loses 2 million tonnes of material per year
- Made up of chalk & till (glacial deposits) which is soft bolder clay
- Features - Caves, Archers & Stacks
- Processes
- Weathering & Mass Movement - Free fall, Mud flows & Slumps
- Erosion - Abrasion, Hydrolic Action & Attrrition
- Transport - Longshore drif & Tidal
- Causes
- Human
- Coastal defences - Hard engineering acts like a groyne, increases erosion further up coast
- Offshore dredging - 4 million tonnes removed in 2000, concerns some illegally removed closer to the shore, increased steepness of sea bed
- Physical
- Geology - lithology is soft & permeable, little supply of material from long-shore drift, no internal structure
- Waves - Wind speed, length of fetch, length of time the wind blows
- Geo-morphology (shape) - breaking point of waves is at the foot of the cliffs, beach presence (sand abs Coastal orbs less wave energy)
- Human
- Consequences
- Physical
- Cliff Retreat - When eroded, if underlying clay is removed the change is permanent, coastline developes a stable shape that lies right angle to the prevailing wind
- Rotational slumping - especially after prolonged rainfall causes curved rupture surface, some internal cohesion, highly saturated toe
- Wildlife - Biodiversity has declined in the salt marshes due to reduced supply in sediment
- Socio-economic
- Cost - Coastal defences are expensive, some sea defences abandoned due to cost
- Settlement Loss - 4km of coastline lost in last 2000 years with at least 30 settlements lost already, main road through Mappleton is only 50m from cliff, propeties loose value
- Economic Loss - Farm land lost or loses value, gas terminals are threatened
- Physical
- Information
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