3.2.5 Coastal Management: Lyme Regis - Case Study

Coastal Management Strategies

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Hard Engineering Involves using artificial structures to manage coastal erosion.

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Soft Engineering Does not involve building artificial structures. But takes a more sustainable and natural approach to managing the coast.

Defence	What is it	Benefits	Costs
SEA WALL	A wall is made out of hard material like concrete that reflects wave energy back to sea	It prevents erosion of the coast. It also acts as a barrier to prevent flooding	It creates a strong backwash, which erodes under the wall. Sea walls are expensive and ugly
GABIONS	A wall of wire cages filled with rocks usually built at the foot of cliffs	The gabions absorb wave energy and reduce erosion. They're cheap & easy	They're ugly and the wire cages erode over time
ROCK ARMOUR	Boulders that are piled up along the coast.	The boulders absorb wave energy and reduce erosion and flooding. It is cheap	Boulders can be moved around and they are hard to get into place as are lacks and heavy
GROYNES	Wooden fences that are built at right angles to the coast. They trap material transported by longshore drift.	They create wider beaches which slow waves. This gives greater protection from flooding & erosion.	They starve beaches of sediment further down the coastline. These then have less protection against erosion.
BEACH REPLENISHMENT	Sand and shingle added to the beach.	It creates wider beaches which slow the waves and protects against flooding and erosion	It is very expensive and needs to be constantly repeated
SAND DUNE REGENERATION	Creating or restoring sand dunes.	Sand dunes provide a barrier between the land and the sea. Wave energy is absorbed which prevents flooding. It is cheap.	The protection is limited to a small area. It is very expensive.

Managed Retreat

Involves removing coastal defences and allowing the sea bed to flood behind.
Benefits:
1. Land will become marshland, protecting land behind from flooding and erosion.
2. Cheap and easy.
3. Creates new habitats.
4. Can cause conflict with landowners.

COASTS – Coastal Management Case Study: LYME REGIS

Location

Small coastal town in SW England. In the heart of a heritage coastline called the Jurassic Coast.

Issues in Lyme Regis

The town is built on unstable cliffs.
It is built on a layer of strong limestone which is very solid. On top of that layer are slippery muds, clays, and sands which slide over the limestone layer to form landslides.
The sea erodes the cliffs at the bottom of the landslide, causing it to become unstable and slip further.
Houses, buildings, and roads become damaged as the land slips towards the sea.

Why does Lyme Regis need protecting?

The local economy depends on tourism as its main source of income.
37,500 people are employed in the tourist sector in the town.
The area generates £800 million per year from tourism.
The town hosts many festivals, including an annual fossil festival.

Management of the Coastline

The Lyme Regis Environmental Improvement Scheme was set up in the early 1990s to provide long-term coastal protection and reduce the threat of landslides.

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Phase 1

New sea wall and promenade constructed to the east of the River Lim.
In the winter of 2003, a £1.4 million emergency project was completed to stabilise the cliffs. 1000 steel pins were used to hold rocks together.

Phase 2

Creation of a wide sandy beach (nourishment) to absorb wave energy and increase the use of the shore.
The beach was nourished with 75,000 tonnes of shingle dredged from the Channel.

Phase 3

Initial plan to prevent landslips and coastal erosion to the west of the Cobb was shelved.
Decided to leave this stretch of the coast alone as the costs outweighed the benefits.

Phase 4

Final phase focused on the coast east of the town.
Cost £20 million and involved constructing a new 390m sea wall in front of the existing wall.

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Advantages

New beaches have increased visitor numbers and sea front businesses are thriving.
New defenses have stopped up to recent landslides.
The harbor is now better protected, benefiting boat owners and fishermen.
Improved amenities can help house insurance.

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Disadvantages

The scheme was very expensive, over £30 million.
The beach needs to be replenished every 3 years.
The sea wall will need replacing in 30 years.
Locals complained about construction noise.
Sea defences may speed up erosion further down the coastline.

Coastal Management: Lyme Regis - Case Study Simplified Revision Notes for GCSE AQA Geography

3.2.5 Coastal Management: Lyme Regis - Case Study

Coastal Management Strategies

Managed Retreat

COASTS – Coastal Management Case Study: LYME REGIS

Location

Issues in Lyme Regis

Why does Lyme Regis need protecting?

Management of the Coastline

Phase 1

Phase 2

Phase 3

Phase 4

Advantages

Disadvantages

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