Vulnerable coastlines

Understanding Vulnerable Coastlines

• Coastal hazards pose a significant risk to areas that either have high population densities or important ecological systems. These are known as vulnerable coastlines.

• A coastline’s vulnerability isn’t just about its susceptibility to physical processes such as erosion or flooding. It also encompasses social, economic and environmental aspects.

Coastal Physical Processes

• Erosion: This is exacerbated by strong winds and waves in coastal areas. Some coasts erode faster than others due to the types of rocks present. Soft rock coasts such as clay are easily eroded producing steep cliffs, while hard rock coasts erode more slowly, forming a rugged coastline.

• Sea-Level Rise: Global warming contributes to the melting of polar ice caps and thermal expansion of seawater, leading to rising sea levels. This intensifies coastal flooding, particularly in low-lying areas.

• Coastal Flooding often occurs due to a combination of high tides, storm surges, or increased rainfall. This is particularly devastating for communities living in flat, coastal plains.

Social and Economic Factors

• Population Density: Highly populated coastal areas face greater risks. More people can succumb to coastal hazards such as tsunamis or hurricanes. Additionally, the demand for land often leads to building closer to the coast, increasing exposure to hazards.

• Economic Activities: Regions that depend on coastal tourism or fisheries are particularly vulnerable as these sectors can be heavily affected by hazards. Coastal hazards can impact infrastructure, interrupt business operations and deter visitors.

Environmental Factors

• Coastal Development: Overdevelopment can disrupt natural coastal processes leading to increased erosion and coastal vulnerability. Building sea defences, for instance, can disrupt longshore drift leading to sediment starvation and enhanced erosion further along the coast.

• Loss of Natural Protection: Destruction of mangroves, coral reefs and sand dunes, often due to developmental activities, increases vulnerability as these ecosystems provide natural coastal defence against wave action and storm surges.

Management of Vulnerable Coastlines

• Hard Engineering Approaches involve the construction of physical structures (like seawalls, groynes, or rock armour) to reduce erosion and flooding, but these can often be expensive and may disrupt natural processes.

• Soft Engineering Approaches are more sustainable and work with natural processes. These include beach nourishment, dune regeneration, and managed retreat, to create buffers and allow areas to flood naturally.

• Planning and Preparation can reduce vulnerability. This includes developing early warning systems for storms or tsunamis, enforcing building regulations to ensure structures are hazard resilient, and creating hazard response plans.

Understanding these aspects can help to predict, mitigate, and recover from coastal hazards, reducing the vulnerability of coastlines.