Seawalls are structures constructed along coastlines to protect against coastal erosion, flooding, and storm surges. They act as barriers, absorbing and deflecting the energy of waves to safeguard infrastructure, communities, and ecosystems.

The four main types include:

• Vertical Seawalls: Are tall, straight structures that directly deflect high energy waves i.e. a storm surge, however they can cause increased beach erosion due to wave reflection.
• Curved or Stepped Seawalls: Are designed to dissipate wave energy, these seawalls reduce erosion more effectively than vertical walls by redirecting waves back to the sea. However they are more expensive to construct due to their complex design.
• Rubblemound (Revetments): Are loped structures made of loose rocks or concrete blocks that absorb wave energy, providing a more natural looking and permeable coastal defence. However they require regular maintenance and can be less effective in extreme weather.
• Hybrid Seawalls: Are a combination of vertical and sloped designs, they are designed for both wave resistance and energy dissipation. Whilst the provide strong wave protection and reduced erosion effects they have higher construction and maintenance cost than any of the above. 

Benefits

• Flood and Erosion Protection: Prevent coastal flooding and erosion from waves and storm surges.
• Long Lifespan: If properly constructed seawalls can last decades with maintenance.
• Create Space: Provide space for infrastructure close to shorelines, such as roads and buildings.
• Improved Safety: Protects coastal communities and assets from extreme weather events.

Criticism or Limitations

• Cost: Construction and maintenance are expensive, especially for large-scale projects.
• Environmental Impact: Can disrupt coastal ecosystems by altering wave patterns and sediment transport.
• Scouring: Vertical walls can cause erosion at their base, leading to eventual failure if not mitigated.
• Aesthetic Issues: Large, artificial structures can impact the natural beauty of coastlines.

Real-life examples in the UK

ARSINOE Case Studies