Holderness Coast: Management Challenges and Strategies
The Holderness Coast requires careful management due to its rapid erosion rates and the complex interplay of natural and human factors affecting the coastline.
Reasons for Management
- Sub-aerial erosion: Rainwater infiltration causes mass movement and cliff collapse.
- Cliff development: Human activities on cliffs accelerate mass movement.
- Boulder clay vulnerability: Cliffs formed by glacial deposits are retreating at an average rate of 1.8 meters per year.
- Sediment budget imbalance: Longshore drift and erosion at cliff bases reduce beach formation, leaving cliffs exposed to further erosion.
Definition: Sediment budget - The balance between sediment inputs and outputs within a coastal system.
Management Strategies
Various approaches have been implemented to manage erosion along the Holderness Coast:
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Hard Engineering:
- Sea walls (e.g., at Hornsea) to reduce erosion and protect cliffs
- Groynes to alter longshore drift and trap sediment
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Managed Retreat:
- No active intervention at Skipsea, allowing natural processes to continue
Highlight: The effectiveness of management strategies varies along the coast, with some areas benefiting while others experience increased erosion rates.
Impacts of Management
The implementation of coastal defenses has led to several consequences:
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Beach morphology changes:
- South of Hornsea, beaches have gentler gradients and store less material, allowing waves to reach cliffs more easily.
- Groynes at Hornsea trap sediment, creating steeper and wider beaches.
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Sediment size distribution:
- Beaches protected by groynes tend to have smaller sediment sizes, as larger particles are trapped upstream.
- Smaller sediment is more easily transported by storm waves, potentially exacerbating erosion.
Example: The groynes at Hornsea have successfully created wider and steeper beaches, providing better protection for the local area. However, this has come at the cost of increased erosion rates in down-drift locations.
