Coastal Landscapes and Change

3.1 Coastal Landscapes and Systems

• Coastal Landscape Variability

  • The UK's coastline is 31,368 km long, featuring diverse landscapes.

  • Examples include:

    • Tropical beaches in the Outer Hebrides (Luskentyre).

    • Rocky coasts in Cornwall.

    • Muddy estuaries like The Wash.

    • Sandy beaches and dunes at Bamburgh, Northumberland.

• Geological Influence on Coastlines

  • Coastal landscapes are shaped by geological factors, including rock type and structure.

  • Resistant rocks (e.g., granite, limestone) withstand erosion better than weaker sedimentary rocks (e.g., clays, sands).

  • Erosional landforms (headlands, cliffs) are common in high-energy environments.

• Coastal Plain Landscapes

  • Eastern and southern coasts of the UK feature low-energy environments with weaker sedimentary rocks.

  • The Wash is the largest estuary in the UK, with diverse habitats.

3.2 The Coast as a System

• Inputs, Processes, and Outputs

  • Coastal systems are driven by wave energy, with sediment supply from various sources.

  • Sediment is transported and deposited, creating landforms.

  • Changes in one component of the system affect the others.

• Sediment Sources

  • Cliffs eroding along the Norfolk coast contribute to sediment supply.

  • Tidal currents and rivers also play a role in sediment transport.

• Classification of Coasts

  • Coasts can be classified based on geology, energy levels, and landforms.

  • The littoral zone is crucial for understanding coastal processes.

3.3 Waves and Beaches

• Wave Formation and Types

  • Waves are generated by wind and vary in size based on wind speed and fetch.

  • Two main types of waves:

    • Constructive Waves: Gentle, build up beaches.

    • Destructive Waves: Steep, erode beaches.

• Beach Morphology

  • Beach profiles change seasonally, with constructive waves creating wider beaches in summer and destructive waves eroding them in winter.

3.4 Coastal Erosion - Processes and Landforms

• Erosional Processes

  • Key processes include hydraulic action, abrasion, and corrosion.

  • Erosion rates vary based on wave energy and rock resistance.

• Landforms Created by Erosion

  • Features include caves, arches, stacks, and wave-cut platforms.

  • The formation of these landforms is a result of continuous erosion and weathering.

3.5 Coastal Transport and Deposition

• Sediment Transport Mechanisms

  • Sediment is transported via traction, saltation, and suspension.

  • Longshore drift is a significant process affecting beach formation.

• Depositional Landforms

  • Spits, barrier beaches, and tombolos are formed through sediment deposition.

  • These features create low-energy environments that support diverse ecosystems.

3.6 Weathering and Mass Movement at the Coast

• Types of Weathering

  • Mechanical, chemical, and biological weathering contribute to coastal erosion.

  • Mass movement processes include slumping, landslides, and soil creep.

• Impact of Weathering on Coastal Landscapes

  • Weathering weakens cliffs, making them more susceptible to erosion and mass movement.

3.7 Sea Level Change

• Types of Sea Level Change

  • Eustatic change: Global sea level rise or fall.

  • Isostatic change: Local land rise or fall due to glacial activity.

• Impacts of Sea Level Rise

  • Coastal areas face increased flooding risks, particularly low-lying regions like Kiribati.

3.8 Holderness and Coastal Erosion

• Geology of Holderness

  • Composed mainly of boulder clay, which is weak and erodes rapidly.

  • The coastline retreats at an alarming rate, with significant erosion recorded.

• Factors Influencing Erosion Rates

  • Wave energy, fetch, and human activities contribute to the high erosion rates along the Holderness coast.

• Coastal Management Challenges

  • Coastal defenses have been implemented, but they can disrupt natural sediment transport and exacerbate erosion elsewhere.

3.9 Coastal Flooding

• Increasing Flood Risks

  • Coastal flooding is exacerbated by subsidence, vegetation removal, and climate change.

  • Bangladesh is particularly vulnerable due to its low-lying geography and dense population.

• Consequences of Flooding

  • Flooding leads to loss of life, property, and agricultural land, highlighting the need for effective coastal management strategies.