UK Coastal Case Study (Landforms + Management)

Key UK Coastal Landforms

Headlands and Bays

Headlands and bays form on coastlines with alternating bands of hard and soft rock. Softer rock erodes faster, creating bays, while harder rock resists erosion and forms headlands.

Example: The Dorset coast has prominent headlands like Portland Bill and bays such as Swanage Bay.

Cliffs and Wave-Cut Platforms

Cliffs are steep rock faces formed by erosion at the base by waves. Over time, the cliff retreats inland, leaving a flat, rocky wave-cut platform at the base, visible at low tide.

Example: The white chalk cliffs at Beachy Head in East Sussex show clear wave-cut platforms.

Caves, Arches, Stacks, and Stumps

These features form through erosion of weaknesses in headlands:

• Caves: Formed when waves erode cracks in the rock.
• Arches: When caves on opposite sides of a headland meet.
• Stacks: When an arch collapses, leaving a pillar of rock isolated from the coast.
• Stumps: When stacks erode further and collapse.

Example: Old Harry Rocks on the Dorset coast show stacks and stumps.

Beaches and Depositional Features

Beaches form where waves deposit sand and shingle. They can be sandy or pebbly depending on the material available. Other depositional features include spits and bars (covered in other topics; see the River Landscapes and Coastal Landscapes sections for more details).

Example: Bournemouth has a wide sandy beach popular for tourism.

Coastal Processes

Erosion Processes

• Hydraulic action: Waves force air into cracks in the rock, causing pressure that breaks the rock apart.
• Abrasion: Rock fragments carried by waves scrape and wear away the coastline.
• Attrition: Rock fragments collide with each other, breaking into smaller, rounder pieces.

Transportation: Longshore Drift

Longshore drift moves sediment along the coast. Waves hit the shore at an angle, carrying material up the beach (swash) and back down at right angles (backwash), moving sediment sideways.

Example: Sediment moves along the Holderness coast from north to south due to prevailing winds.

Reasons for Deposition

Deposition occurs when waves lose energy, such as in sheltered areas, where the coastline changes direction, or when the amount of sediment exceeds the energy of the waves.

Mass Movement Types

• Slumping: Saturated soil and weak rock slip down a curved surface.
• Rockfalls: Pieces of rock break off cliffs and fall due to weathering and gravity.
• Sliding: Large blocks of rock slide down a slope.

Case Study: Holderness Coast

Location and Physical Characteristics

The Holderness Coast is on the east coast of England, stretching from Flamborough Head to Spurn Head. It is one of the fastest eroding coastlines in Europe, made mainly of soft boulder clay.

Examples of Landforms Present

• Cliffs: Soft boulder clay cliffs retreat rapidly due to erosion and slumping.
• Wave-cut platforms: Found at the base of eroding cliffs.
• Spurn Head: A spit formed by longshore drift at the southern end of the coast.
• Headlands and bays: Flamborough Head is a chalk headland, contrasting with the softer cliffs to the south.

Human Use and Impacts

The coast supports farming, tourism, and settlements like Bridlington and Hornsea. Rapid erosion threatens homes, farmland, and infrastructure, causing economic losses.

Environmental Significance

The area is important for wildlife, including seabird colonies on Flamborough Head. Coastal habitats are sensitive to erosion and human activity.

Coastal Management Strategies

Hard Engineering

• Sea walls: Concrete or rock walls that reflect wave energy, protecting the coast behind.
• Groynes: Wooden or rock barriers built at right angles to the coast to trap sediment and reduce longshore drift.
• Rock armour: Large boulders placed at the base of cliffs to absorb wave energy.

Hard engineering is expensive but effective in protecting specific areas.

Soft Engineering

• Beach nourishment: Adding sand or shingle to beaches to replace eroded material and absorb wave energy.
• Dune regeneration: Planting vegetation to stabilise sand dunes and prevent erosion.

Soft engineering works with natural processes and is often cheaper and more sustainable.

Managed Retreat

Allowing certain low-value areas to erode naturally, creating new habitats like salt marshes that protect inland areas by absorbing wave energy.

Effectiveness and Conflicts

• Hard engineering protects valuable land but can be costly and cause increased erosion elsewhere.
• Soft engineering is less intrusive but may require ongoing maintenance.
• Managed retreat can be controversial as it involves loss of land and property.

Example: At Mappleton, groynes and rock armour have slowed erosion, protecting the village but causing increased erosion further south.

Learning Example: Calculating Rate of Coastal Erosion

If the Holderness Coast erodes by 2 metres per year, how much land is lost in 10 years?

Calculation:

$\text{Land lost} = 2\,\mathrm{m/year} \times 10\,\mathrm{years} = 20\,\mathrm{m}$

This means 20 metres of coastline will have disappeared after 10 years.