Coasts 6 - The Holderness Coast Flashcards
How long is the coastline?
61km - stretches from Flamborough to Spurn Head
What are the cliffs made up of?
Till (boulder clay)
What is the coast exposed to?
Powerful destructive waves from the North Sea during storms
What 4 coastal processes operate in the area
- Mass movement
- Erosion
- Transportation
- Deposition
What erosion happens
The soft boulder clay is easily eroded by wave action. In Great Cowden, the rate of erosion has been over 10m / year in recent years
What mass movement happens
The boulder clay is prone to slumping when wet. Water makes the clay heavier and acts as a lubricant between particles, making it unstable
What transportation happens
Prevailing winds from the northeast transport material south. These winds create an ocean current, which transports material south by longshore drift. Rapid erosion means there’s plenty of sediment to be transported
What is deposition?
When the ocean current meets the outflow of the Humber river, the flow becomes turbulent and sediment is deposited
What 3 coastal landscapes are found in the north
- Steep - chalk cliffs
- Wave - cut platforms
- Sandy beaches
What is the south like
Less-steep boulder - clay cliffs and around Spurn Head there are depositional features
What are the headland and wave-cut platforms like?
To the North of the area, the boulder clay overlies chalk. The chalk is harder and less easily eroded, so formed a headland (Flamborough Head) and wave-cut platforms such as Sewerby.
What are beaches like?
South of Flamborough Head and is sheltered form the wind and waves and a wide sand and pebble beach has formed near Bridlington
What are sand dunes like
Around Spurn Head, material transported by the wind is deposited forming sand dunes
What are the spits like
Created by erosion and LSD with a recurved end across the mouth of the Humber Estuary - called Spurn Head. To the landward side of the spit, estuarine mudflats and saltmarshes have formed
What are slumping cliffs like
Frequent slumps give the boulder clay cliffs a distinctive shape. In some places, several slumps have occurred and not been eroded, making the cliff tired. Slumps are common around Atwick Sands
How much has the Holderness Coastline retreated
4km in the last 2000 years
How many villages have been lost because of tis retreat?
30
What 3 main issues has this ongoing erosion caused
- Loss of settlements and livelihoods
- Loss of infrastructure
- Loss of Sites of Special Scientific Intrest (SSSIs)
What has happened because of Loss of settlements and livelihoods
The village of Skips is at risk and 80,000m of good quality farmland is lost each year at the coast which has huge effects on farmers livelihoods
What has happened because of loss of infrastructure
The gas terminal at Easington is only 25m from the cliff edge
What has happened because of Loss of Sites of Special Scientific Intrest (SSSIs)
The lagoons near Easington provide habitats for birds
How much of the coastline is protected by hard engineering
11.4km
What protects Bridlington (2)
A 4.7km sea wall as well as timber groins
What protects the village at Hornsea (3)
Concrete sea wall, timber groynes and rip rap
What happened in Mapleton in 1991
2 rock groynes and a 500m long revetment. They cost £2 million
How was the caravan park in Skipsea protected
Gabions
What protection is Withernsea (3)
Groynes, sea wall and rip rap
What protects the Easington Gas Terminal
Revetment
What protects the eastern side of Spurn Head (2)
Groynes and rip rap
How do groynes protect the area
Trap sediment and increase the width of the beaches. This protects the local area but increases it in other places
What happens to the sediment produced by erosion
Washed into an estuary (where it helps form tidal mudflats)
What is happening because of the protection?
The formation of bays
What happens as these bays develop
wave pressure on the headlands increase and eventually the cost of maintaining the sea defence becomes too high
What do these problems mean
The existing schemes become unsustainable
What does the SMP recommend for the Holderness for the next 50 years?
Hold the line at some settlements and do nothing at others
What else has been recommended
Managed realingment
What will happen because of this managed realingment
Relocate caravan parks further inland and allowing the land they’re on erode
Why is this more sustainable
It allows the coast to erode normally without endangering businesses
Whats an issue with this
The amount of compensation businesses will get for relocating and relocation isnt always possible due to land shortage
What happened in 1995
Holderness Borough Council tried to stop Spurn Head from erosion and overwashing - do nothing became the new strategy
Why was this good
Saves money and allows the spit to function naturally
What is a negative of over washing
Damages marsh environments behind the spit.
What protects Easington Gas Terminal
Rock revetments and the SMP recommend that these defences are maintained as long as the gas terminal is operating
WHats an issue with this?
The defences only span 1km in front of the gas terminal meaning the village isnt protected
