Detailed Notes - Coastal Landscapes and Change - Edexcel Geography A-level

Coasts as Open Systems
Inputs from terrestrial, atmospheric, and oceanic systems.
Closed systems in specific contexts (scientific research, management).
Sediment Cells: Closed systems for sediment, 11 in England and Wales.
Components:
- Sources: Origin points (e.g., cliffs, offshore bars).
- Through flows: Movement along the shore (longshore drift).
- Sinks: Deposition areas (e.g., spits, beaches).
Dynamic Equilibrium: Inputs and outputs balanced but changeable.
Human and physical actions can impact this balance.
Feedback Loops:- Negative Feedback: Stabilizes changes (e.g., storm erodes beach, leading to sediment deposition).- Positive Feedback: Exaggerates changes (e.g., human activity increases erosion rate of dunes).

Definition: Coastal area affected by wave action, constantly changing.
Factors Influencing Changes:
- Short-term (tides, storm surges) and long-term (sea level, climate change).
Subzones:
- Backshore: Above high tide, rarely impacted.
- Foreshore: Most active wave processes occur here.
- Offshore: Open sea beyond the foreshore.
- Valentine’s Classification:
- Advancing Coastlines: Land emergence/deposition.
- Retreating Coastlines: Land submergence/erosion.

Erosional Processes:
Types of Erosion:
- Corrasion: Sediment hurled against cliffs at high tide.
- Abrasion: Sediment wears down land over time.
- Attrition: Rocks wear each other down.
- Hydraulic Action: Waves force air into rock cracks, causing erosion.
- Corrosion (Solution): Acidic seawater erodes alkaline rocks.
- Wave Quarrying: High-pressure waves remove rock or debris.
Conditions for Highest Erosion Rates:- High waves with long fetch.- Perpendicular wave approach.- High tide presence.- Heavy rainfall and winter waves.

Factors of Vulnerability:
- Rock Type: Clastic (e.g., sandstone) vs. crystalline (e.g., granite).
- Cracks and Fractures: More weaknesses lead to higher vulnerability.
- Lithology:
  - Igneous: Slowest erosion.
  - Metamorphic: Slow erosion.
  - Sedimentary: Fastest erosion.
- Erosional Landforms:
- Caves, Arches, Stacks & Stumps: Sequence from marine erosion.
- Wave-cut Notch and Platform: Created through marine erosion of cliff bases.

Retreating Cliffs: Formation through repeated wave-cut processes.
Blowholes: Intersection of deepening caves and potholes.
Transport and Deposition:
- Longshore Drift (LSD): Movement of sediment along the beach.
  - Process description: Waves impact shoreline at an angle.
- Other Sediment Transport Mechanisms:
  - Traction, Saltation, Suspension, Solution.
- Effectiveness of Transportation: Influenced by wave angle.
- Deposition: Occurs when waves lose energy.

Spits: Formed by longshore drift.
Bars: Spits that connect two coastlines across a bay.
Tombolo: Connects mainland to offshore islands.
Cuspate Forelands: Result from longshore drift meeting on triangular headlands.
Offshore Bars: Formed from deposited sand offshore due to wave action.
Formation of Sand Dunes: Requires specific climatic conditions and processes of succession.

Stages of Dune Development:
- Embryo Dunes: Initial, with weak stabilization.
- Yellow Dunes: Development of vegetation.
- Grey Dunes: Mature with increased nutrients and soil stability.
- Dune Slack: Moisture-loving plants develop.
- Heath and Woodland: Mature vegetation forms stable ecosystems.

Weathering Types:
- Mechanical Weathering: Freeze-thaw, salt crystallization.
- Chemical Weathering: Carbonation, oxidation, solution.
- Biological Weathering: Plant roots, bird burrowing, etc.
Mass Movement: Determined by sediment weight and slope angle.
- Types of Mass Movement:
  - Flows: Soil creep, solifluction, mudflows.
  - Slides: Rock falls, rock slides, slumps.

Stabilization Role: Roots bind soil, reduce erosion.
Types of Coastal Plants:
- Xerophytes: Dry condition tolerance.
- Halophytes: Salt condition tolerance.
Plant Succession Overview:
- Pioneer Plants: Initiate stabilization.
- Nutrient Release: Reduces soil salinity over time.

Energy Levels of Coastlines:
- High-energy: Rocky, eroding landscapes.
- Low-energy: Sandy, depositional zones.
Wave Characteristics: Types of waves and their effects (constructive vs destructive).
Sea Level Changes: Short-term (tides) and long-term (eustatic changes).

Eustatic vs. Isostatic Sea Level Change:
- Eustatic: Global thermal expansion causing sea level rise.
- Isostatic: Localized changes due to ice melting or tectonic activity.
Impact of Coastalization: Increased vulnerability to flooding and storm surges.

Strategies: Varied based on economic, ecological, and social values.
Types: Hard engineering (e.g., sea walls) vs. soft engineering strategies (e.g., beach nourishment).
Coastal Decision Making: Cost-benefit analysis (CBA) for effective resource allocation.

Sustainable Practices: Resource management, community education, monitoring changes.
Conflict Over Policy: Differing opinions on protection and relocation impacts.

Consequences for Sediment Cells: Erosion shifts due to management strategies, e.g., sea walls leading to increased erosion elsewhere.