Holderness Coast Case Study: Intentional Impacts and Management
The Holderness Coast in Yorkshire, England, is renowned for its rapid erosion rates, making it a crucial case study for A-level geography students. This coastline, stretching from Flamborough Head to Spurn Head, exemplifies the complex interplay between natural processes and human intervention in coastal management.
Highlight: The Holderness Coast is eroding at an average rate of 1.8 meters per year, with 29 villages lost to the sea since Roman times.
Geological Context
The coast is primarily composed of boulder clay cliffs, formed by material deposited by ice sheets. This geological composition contributes significantly to the area's vulnerability to erosion.
Vocabulary: Boulder clay, also known as glacial till, is unsorted glacial sediment.
Erosion Processes
Several erosion processes are at work along the Holderness Coast:
- Sub-aerial erosion: Rainwater infiltrates the clay, increasing its weight and leading to mass movement and cliff collapse.
- Marine erosion: Wave action at the cliff base, particularly during storms, undermines the cliffs.
- Human impact: Development on cliff tops can accelerate mass movement.
Example: Rip currents excavate cliff material, forming small indentations called 'ords', which further contribute to erosion.
Management Strategies
Various coastal management strategies have been implemented along the Holderness Coast:
Hornsea
- Groynes installed at a cost of £5.2 million
- Steel 'doors' to protect beach entrances
- Sea wall to defend the promenade and holiday resort
Definition: Groynes are structures built perpendicular to the shoreline to trap sediment and reduce longshore drift.
Mappleton
- Two rock groynes and a revetment constructed in 1991 £2.1millionEUfunding
- Cliffs regraded to reduce slumping
Easington
- Rock armour revetments protect the natural gas terminal, which handles 25% of North Sea gas production
Skipsea and Kilnsea
- No active intervention at Skipsea due to low-value land and small population
- Managed realignment at Kilnsea, with the council no longer maintaining sea defenses
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Consequences of Management
The implemented strategies have had various impacts on the coastal system:
- Reduced erosion rates in protected areas
- Altered sediment transport patterns due to groynes
- Changes in beach profiles and sediment composition
- Increased erosion in unprotected areas downdrift of defenses
Highlight: Hard engineering reduces erosion and the flow of material into the sediment budget from cliff erosion, but can lead to increased erosion elsewhere along the coast.
This Holderness Coast case study provides valuable insights into the challenges of coastal management, balancing the need for protection with the natural processes of erosion and sediment transport. It serves as an excellent example for students studying coastal erosion, geology, and management strategies in A-level geography courses.
