3.8 The Holderness Coastline

Question 1

What is some context and facts on how fast the Holderness is eroding?

Answer 1

In places, the coastline here has eroded 7m in just a year
It’s the fastest eroding coastline in Europe- on average it loses 2m every year
Since, Roman times, the Holderness coast has retreated by 4km and at least 29 villages have been lost to the sea.

Question 2

What are the three main reasons as to why the coastline is retreating so rapidly?

Answer 2

-geology
-fetch
-longshore drift and beach material

Question 3

Where is the Holderness?

Answer 3

Along the coast of the East Riding of Yorkshire, which stretches between Bridlington and Flamborough Head in the north, and Spurn Head in the south

Question 4

How has its geology impacted the Holderness coastline?

Answer 4

-Most of the Holderness consists of boulder clay, also known as glacial till and is a mixture of fine clays, sands and boulders deposited by glaciers after the Ice Age. Boulder clay is structurally weak, and has little resistance to erosion. It produces shallow, sloping cliffs between 5 and 20 metres high
-The chalk band that has surrounded the boulder clay has created a headland at Flamborough Head. Erosion along fault lines and bedding planes has created features such as cliffs, arches and stacks

Question 5

How does its fetch affect the Holderness coastline?

Answer 5

• wave energy depends on fetch (how far the waves have travelled).
  The Holderness is exposed to winds and waves from the north east , with a small fetch of around 500-800km across the north sea

Question 6

What other factors influence the waves at the Holderness, increasing their size and power?

Answer 6

-Currents (or swell) circulate around the UK from the Atlantic ocean into the North Sea. The Atlantic’s fetch is 5000km or more, so its currents add energy to the waves in the North Sea. Therefore, there are often powerful destructive waves at work along this coastline
-Low pressure weather systems and winter storms passing over the North Sea are intense, producing locally strong waves and winds. Low pressure air weighs less, raising sea levels, which, in turn, produce much higher tides than normal
-The sea floor is relatively deep along the Holderness coast, so waves reach the cliff without being weakened by friction
-Small, almost enclosed sea often generates huge waves in storms. Waves move within the sea, but cannot disperse their energy.

Question 7

How does longshore drift and beach material affect erosion at the Holderness coastline?

Answer 7

-The boulder clay erodes, which is then easily transported out to sea in suspension, rather than accumulating on shore as a beach. Although there are beaches, they are narrow and offer little friction to absorb wave energy
-The tides flow southwards, transporting sand south by longshore drift, and leaving the cliffs at Holderness poorly protected against wave attack. Beaches at Hornsea have reduced width, because an imbalance exists between the input of sand and the removal of sand.

Question 8

What weathering processes take place at the Holderness coastline?

Answer 8

• Chemical weathering is relatively ineffective at Holderness, except on chalk cliffs at Flamborough Head. Mechanical and biological weathering are far more significant. The Holderness undergoes freeze-thaw weathering and the alternate wetting and drying of the boulder clay which makes it crumbly in dry periods.

Question 9

What kind of mass movement takes place at the Holderness coastline?

Answer 9

Slumping
The alternate wetting and drying of the clay causes expansion and shrinkage- producing cracks during long, dry periods. Subsequent rains then enter the cracked clay and percolate into the cliff, which becomes lubricated and much heavier. The weakened cliff cannot support the extra weight, and the clay slides downslope under gravity.
The slumped material collects at the base and then is removed by the sea

Question 10

What are some of the human factors, which affect the retreat of the cliff

Answer 10

-The presence of people along the coastline turns physical processes into hazards. Increasing population levels due to retirement and the development of leisure facilities have occurred, as well as caravan parks.
-Interfering with natural processes such as long shore drift has adverse effects. Groins mean that sediment is being prevented from building beaches elsewhere . Rapid erosion rates at sites such as Great Cowden may be due to this sediment starvation effect
-Global warming is creating a rise of sea levels and increasing storminess, causing a greater risk of erosion.