Coasts Revision Part 2

Coasts Revision Part 2

Coasts Case Study: Holderness Coast

North East of England

Fastest eroding coastline in Europe

Strong prevailing winds lead to high amounts of longshore drift.

Mostly made of up of soft rock - boulder clay.

Reasons for management

• The coastline is rapidly eroding at an average of 1.8 metres a year. There are several reasons why the coast at Holderness is eroding so quickly:

• Rock type - the cliffs are made from less-resistant boulder clay (made from sands and clays) which slumps when wet.

• Naturally narrow beaches - these beaches give less protection to the coast as it doesn't reduce the power of the waves.

• Man-made structures - groynes have been installed to stop long-shore drift. This narrows unprotected beaches elsewhere even more.

• Powerful waves - waves at Holderness travel long distances over the North Sea (so have a long fetch) which means they will increase in energy.

Types of Management along the Holderness Coast

• Bridlington is protected by a 4.7 km long sea wall.

• Hornsea is protected by a sea wall, groynes and rock armour.

• Coastal management at Withersea has tried to make the beach wider by using groynes, and also uses a seawall to protect the coast.

• Mappleton is protected by rock groynes.

• Spurn Head is protected with groynes and rock armour.

Let's see what you can remember about hard and soft engineering strategies at coastlines.

Multiple Select

Which of the following methods are hard engineering strategies at the coast?

• Managed Retreat

• Rock Armour

• Sea Wall

• Beach Nourishment

Multiple Select

Which of the following are soft engineering strategies found at coasts?

• Managed Retreat

• Groynes

• Rock Armour

• Beach Nourishment

Hard Engineering Strategies

• Sea wall -absorbs the energy from the waves. Very effective, but also expensive and has a negative environmental impact.

• Gabions - small rocks put in cages. Again absorbs wave energy, cheap to construct. However, they break easily and look unnatural.

• Rock Armour - boulders placed at strategic places along the coast to absorb wave energy by breaking the waves. Cheaper than a sea wall, and can be used for fishing. Don't always fit in with the local area.

• Groynes - wooden structure aimed at trapping sediment moved by longshore drift - so builds up the beach. However, it can starve a beach in other areas, they look unattractive and rot over time.

Soft Engineering Strategies

• Beach Nourishment - replacing sand that has been transported elsewhere. Cheap, more sand will slow down the waves. However, has to be done regularly to be effective.

• Managed retreat - doing nothing in one area of the coast which is seen as less valuable, to reduce the erosion in another part of the coast with is more valuable.

Poll

Which hard engineering strategy do you think is the most effective?

• Sea Wall

• Gabions

• Rock Armour

• Groynes

Open Ended

Explain why the hard engineering strategy you chose is the most effective?

Poll

Which soft engineering strategy do you think is the most effective?

• Managed Retreat

• Beach Nourishment

Open Ended

Explain why the soft engineering strategy you chose is the most effective.

Open up the google word document I have shared with you and attempt the question. ‘Hard engineering strategies should always be used over soft engineering strategies to protect the coast from erosion’ Do you agree? (6 marks) 

Remember - 6 marks needs development. When giving your opinion, you always have to give the other side as well!