The purpose of coastal management

Coastal management involves strategies and actions designed to safeguard both people and the environment from the destructive effects of erosion and flooding along coastlines. However, resources and funding for such initiatives are often limited, meaning that not every coastal area can be protected or managed effectively.

Types of coastal defences: hard engineering methods

Hard engineering refers to the construction of man-made structures aimed at controlling the sea's flow to minimise flooding and erosion.

Common hard engineering techniques

• Sea wall - A sturdy barrier, often made of concrete, built along the coast to reflect wave energy back to the sea.
  • Benefits - Effectively prevents coastal erosion and acts as a shield against flooding.
  • Drawbacks - Generates a powerful backwash that can erode the foundation beneath the wall; extremely expensive to construct and maintain.
• Rip-rap (rock armour) - Large boulders stacked along the shoreline to absorb wave energy, with gaps allowing water to pass through.
  • Benefits - Reduces both erosion and flooding by dissipating wave energy; relatively inexpensive compared to other hard engineering options.
  • Drawbacks - Strong waves can displace boulders, necessitating frequent replacement; prevents cliff erosion, reducing natural beach replenishment; can lower beach levels over time.
• Groynes - Structures, often made of wood or stone, built perpendicular to the coastline to trap sediment moved by longshore drift.
  • Benefits - Builds up wider beaches that slow down waves, offering protection against flooding and erosion; cost-effective compared to other hard defences.
  • Drawbacks - Deprives beaches further along the coast of sediment, making them narrower and less protective, which can increase erosion and flooding risks in those areas.

Types of coastal defences: soft engineering methods

Soft engineering involves working with natural processes of the sea to reduce the impacts of flooding and erosion.

Common soft engineering techniques

• Beach nourishment - The process of adding sand or shingle to the upper parts of beaches, sourced from other locations such as offshore areas or lower beach sections.
  • Benefits - Widens beaches, which slows wave energy and enhances protection from flooding and erosion.
  • Drawbacks - Extracting material from the seabed can harm marine life, such as corals and sponges; very costly and needs regular repetition to maintain effectiveness.
• Managed retreat - Involves dismantling existing coastal defences to allow controlled flooding of certain areas, which over time transform into marshland.
  • Benefits - Potentially more cost-effective in the long term as it requires minimal maintenance; creates new marshland habitats for diverse plant and animal species.
  • Drawbacks - Deciding which areas to flood can lead to disputes, especially if it involves relocating communities in low-lying areas; saltwater intrusion can negatively affect existing ecosystems.

The impact of coastal defences on coastal processes and landscapes

Coastal defences significantly alter natural coastal processes and landscapes by interfering with sediment movement and erosion patterns.

Effects on coastal processes and landscapes

• Longshore drift disruption - This natural process moves sediment along the coast, but defences like groynes interrupt this flow.
• Erosion and deposition patterns - Hard engineering structures prevent erosion in protected zones but may increase it elsewhere.
• Landscape alteration - Different types of defences create varied coastal landscapes.