The Holderness coastline Flashcards
General facts
The Holderness coastline is 61km long- it stretches from Flamborough head to Spurn head.
Most of the cliffs are made of till (boulder clay), and the coast is exposed to powerful destructive waves from the North Sea during storms.
Coastal Processes-Erosion
The soft boulder clay is easily eroded by wave action. In some places, e.g. Great Cowden, the rate of erosion has been over 10 m/year in recent years.
Coastal Processes-Mass movement
The boulder clay is also prone to slumping when it’s wet. Water makes the clay heavier and acts as a lubricant between particles, which makes it unstable.
Coastal Processes-Transportation
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.
Coastal Processes-Deposition
Where the ocean currents meets the outflow of the Humber River, the flow becomes turbulent and sediment is deposited.
Coastal Processes creating distinctive landscapes-Beaches
They are to the south of Flamborough Head is sheltered from wind and waves, and a wide sand and pebble beach has formed near Bridlington.
Coastal Processes creating distinctive landscapes-Sand dunes
Around Spurn head, material transported by wind is deposited, forming sand dunes
Coastal Processes creating distinctive landscapes-Spit
Erosion and longshore drift have created a spit with a recurved end across the mouth of the Humber Estuary- this is called Spurn Head. To the landward side of the spit, estuarine mudflats and saltmarshes have formed.
Coastal Processes creating distinctive landscapes-Headland and wave-cut platforms
To the north of the area, the boulder clay overlies chalk. The chalk is harder 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
Coastal Processes creating distinctive landscapes-Slumping Cliffs
Frequent slumps give the boulder clay cliffs a distinctive shape. In some locations, several slumps have occurred and have not yet been eroded, making the cliff tiered. For example, slumps are common around Atwick sands.
Coastline needs to be managed
The Holderness coastline has retreated by around 4km over the past 2000 years. Around 30 villages have been lost.
Erosion on the Holderness coastline has caused social, economic and environmental problems
Loss of settlements and livelihoods- the village Skipsea is at risk and 80000 m^2 of good quality farmland is lost each year on the Holderness coast, which has a huge effect on farmer’s livelihoods.
Loss of infrastructure- the gas terminal at Easington is only 25m from the cliff edge
Loss of sites of special scientific interests- the lagoons near Easington provide habitats for birds.
Hard engineering
A total of 11.4 km of the 61 km coastline is currently protected by hard engineering:
There’s a concrete sea wall, timber groynes and riprap at Hornsea that protect the village.
Two rock groynes and a 500 m long revetment were built at Mappleton in 1991. They cost £2 million and were built to protect the village and the B1242 coastal road.
Current defences/schemes are unstable
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). E.g. the Mappleton scheme has caused increased erosion of the cliffs south of Mappleton. Cowden Farm, just south of Mappleton, is now at risk of falling into the sea.
The sediment produced from the erosion of the Holderness coastline is normally washed into the Humber Estuary (where it helps to form tidal mudflats) and down the Lincolnshire coast. Reduction in this sediment increases the risk of flooding along the Humber Estuary, and increases erosion along the Lincolnshire coast.
SMP
The SMP for Holderness for the next 50 years recommends holding the line’ at some settlements (e.g. at 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.
