Coastal Management: Soft and Hard Engineering

Overview

• Coastal management is split into two main types:
  • Hard Engineering: Expensive, lasts longer, but less aesthetically pleasing.
  • Soft Engineering: Less expensive, doesn't last as long, more visually appealing, especially in tourist areas.
• Exam questions may involve justifying or evaluating which method is best based on cost, maintenance, and longevity.

Hard Engineering

1. Rock Armor (Rip Rap)

• Large, heavy rocks (often imported from Norway).
• Effective and long-lasting sea defenses.
• High cost, but requires no maintenance.
• Aesthetic concerns: Some believe they are not visually appealing.

2. Groynes

• Structures that jut out perpendicular to the coast.
• Function: Capture sediment and reduce longshore drift (do not stop it).
• Benefits: Maintain healthy beaches by catching sediment.
• Limitations: Can be devastated by storms, moderate cost, high maintenance.

3. Seawalls

• Act as barriers against destructive waves, can be curved or stepped.
• Curved Seawalls: Reflect wave energy back onto itself.
• Stepped Seawalls: Dissipate wave energy in steps, reducing damage.
• Last up to 100 years but are very expensive.
• Not suitable for all areas due to accessibility and aesthetic concerns.

Soft Engineering

1. Beach Recycling

• Movement of sediment from one part of the beach to another.
• Uses trucks and diggers to redistribute sediment.
• Low cost, visually unobtrusive.
• Limitations: Not effective against storms.

2. Beach Reprofiling

• Alters the slope of the beach to increase its height, making it less vulnerable to storms.
• Simple, low-cost operation using diggers.
• Visually appealing, often unnoticed by the public.

3. Beach Replenishment

• Sand and shingle are pumped onto the beach from offshore sources.
• Maintains the natural aesthetic of the beach.
• Moderate cost, effective, and quick.

4. Managed Retreat

• Allowing the sea to retake land in a controlled manner (e.g., Medmerry).
• Old sea defenses are removed, creating new natural habitats like salt marshes.
• Cost-effective, promotes biodiversity, and increases habitats for wildlife.

Conclusion

• Hard engineering offers long-lasting protection but is costly and less visually appealing.
• Soft engineering provides a more natural look, lower cost, but requires frequent maintenance and is vulnerable to severe storms.
• Managed retreat combines elements of both hard and soft engineering, enhancing natural environments while providing effective coastal defense.