Coasts - Local Coastal Environment Case Study Flashcards
Where is the Holderness coastline located?
The Holderness Coast is located on theeast coast of England near Yorkshire and Kingston upon Hull. It stretches from Flamborough Head in the north to Spurn Point in the south.
How long is the Holderness coastline?
61km long
What are the cliffs made from on the Holderness?
Most of the cliffs are made from till (boulder clay)
Where is erosion occurring on the Holderness?
The soft boulder clay is easily eroded by wave action. In some places, e.g. Great Cowden, the rate of erosion has been over 10m/year in recent years.
Where is mass movement occuring on the Holderness?
The boulder clay is also prone to slumping when its wet. Water makes the clay heavier and acts as a lubricant between the particles, which makes it unstable.
Where is transportation occuring on the Holderness?
Prevailing winds from the northeast transport material southwards. These winds also create an ocean current, which transports material south by longshore drift. Rapid erosion means there is always plenty of sediment to be transported.
Where is deposition occurring on the Holderness?
Where the ocean current meets the outflow of the Humber River, the flow becomes turbulent and sediment is deposited.
Where are headlands and wave-cut platforms located on the Holderness?
To the north of the area, the boulder clay overlies chalk. The chalk is more resistant and less easily eroded, so it has formed a headland (Flamborough Head) and wave-cut platforms, such as those near Sewerby. Flamborough Head has features such as stacks, caves and arches.
Where are slumping cliffs located on the Holderness?
Frequent slumps give the boulder clay cliffs a distinctive shap. In some locations several slumps have occurred and not yet been eroded, making the cliff tiered. For example, slumps are common around Atwick Sands.
Where are beaches located on the Holderness?
The area to the south of Flamborough Head is sheltered from wind and waves, and a wide sand and pebble beach has formed near Bridlington.
Where are sand dunes located on the Holderness?
Around Spurn Head, material transported by the wind is deposited, forming sand dunes.
Where is the spit located on the Holderness?
Erosion and longshore drift have created a spit with a recurved end across the nouth of the Humber Estuary, this is called Spurn Head. To the landward side of the spit, estuarine mudflats and saltmarshes have formed.
How much has the Holderness coastline retreated in the past 2000 years?
Around 4km
How many villages have been lost in the last 2000 years along the Holderness coastline?
Around 30 villages have been lost.
What social, economic and environmental problems could be caused by the ongoing erosion?
1) Loss of settlements and livelihoods - the village of Skipsea is at risk and 80,000 sq km of good quality farmland is lost each year.
2) Loss of infrastructure - the gas terminal at Easington is only 25m from the cliff edge.
3) Loss of Sites of Special Scientific Interest (SSSIs) - the lagoons near Easington provide habitats for birds.
How much of the 61km of the Holderness is currently protected by hard engineering?
11.4km
What hard engineering strategies are in place along the Holderness coastline?
- Bridlington - is protected by a 4.7km sea wall as well as timber groynes.
- Hornsea - concrete sea wall, timber groynes and riprap.
- Mappleton - two rock groynes and a 500m long reventment (cost £2 million).
- Skipsea - gabions. Withernsea - groynes and sea wall.
- Easington Gas Terminal - revetment.
- Spurn Head (eastern side) - groynes and riprap
How are the existing schemes on the Holderness coastline not sustainable?
1) The groynes trap sediment, increasing the width of the beaches. This protects the local area but increases erosion of the cliffs down-drift, as the material eroded from the beaches there isn’t replenished. The Mappleton scheme has caused increased erosion of the cliffs south of Mappleton, Cowden Farm is now at risk of falling into the sea.
2) The protection of local areas is leading to the formation of bays between those areas. As bays develop the wave pressure on headlands will increase and eventually the cost of maintaining the sea defences may become too high.
What is the SMP for Holdernes for the next 50 years?
The SMP for Holderness for the next 50 years recommends ‘holding the line’ at some settlements (Bridlington, Withernsea, Hornsea, Mappleton and Easington Gas Terminal) and ‘doing nothing’ along less populated stretches. However, this is unpopular with owners of land or property along the stretches where nothing is being done.
Why has managed realignment been suggested?
Managed realignment has been suggested, this would be more a sustainable scheme as it would allow the coast to erode as normal without endangering businesses. However, there are issues surrounding how much compensation businesses will get for relocating and relocation is not always possible.
