Coastal management (Edexcel GCSE Geography A): Revision Notes

Coastal management

Understanding coastal management strategies

Coastal management involves protecting coastlines from erosion and flooding using various techniques. These methods are essential because coastal areas face constant threats from wave action, storms, and rising sea levels. Each management technique brings both benefits and drawbacks that must be carefully weighed, particularly because implementing one solution can sometimes create problems elsewhere along the coast.

Hard engineering approaches

Hard engineering involves constructing artificial barriers and structures to provide direct protection against coastal erosion and flooding. These techniques typically offer strong, immediate defence but come with higher costs and can alter the natural appearance of coastlines.

Sea walls

Sea walls are robust concrete or stone barriers constructed along the shoreline to deflect wave energy away from the land. These structures create a solid defence between the sea and valuable coastal property or infrastructure.

The main advantage of sea walls is their effectiveness in protecting cliffs and buildings from wave attack. They provide reliable, long-term protection when properly maintained and can save valuable coastal property from destruction.

However, sea walls are extremely expensive to build and maintain, costing between $5,000 -$10,000 per metre. They can also create an artificial appearance that disrupts the natural beauty of coastal landscapes, potentially affecting tourism and local wildlife habitats.

Groynes

Groynes are barriers built at right angles to the coastline, extending from the beach into the sea. These structures work by interrupting longshore drift - the natural movement of sand and sediment along the coast - causing beach material to accumulate on one side.

The downside is that whilst groynes trap sediment on one side, they can leave coastal areas further along the shore starved of beach material, potentially increasing erosion in those locations. This demonstrates how coastal management decisions can have knock-on effects along the coastline.

Rip rap defences

Rip rap, also known as rock armour, consists of large rocks or concrete blocks placed along the shoreline. Unlike solid sea walls, these loose materials allow waves to lose energy as water moves through the gaps between the rocks.

Rip rap effectively absorbs wave energy rather than simply reflecting it back to sea, which can help reduce the risk of increased erosion elsewhere. These defences are also more cost-effective than sea walls, typically costing between $1,000 -$3,000 per metre.

The main disadvantages include the possibility of rocks being displaced during severe storms, requiring maintenance and replacement. Additionally, whilst more natural-looking than concrete sea walls, rip rap can still appear artificial in some coastal environments.

Soft engineering approaches

Soft engineering works alongside natural coastal processes rather than opposing them. These methods tend to be more environmentally sustainable and cost-effective, though they often require ongoing management and maintenance to remain effective.

Beach replenishment

Beach replenishment involves artificially adding sand or other sediment to beaches that have been eroded. This material is typically sourced from offshore sand banks or areas where sediment is naturally abundant.

This technique offers several advantages: it reduces wave energy by providing a natural buffer zone, maintains attractive beaches for tourism and recreation, and is very cost-effective at approximately $200 per metre. Replenished beaches look completely natural and can support local ecosystems.

The main challenge with beach replenishment is that the added sand can be gradually washed away by waves and tides, meaning the process may need to be repeated every few years. Finding suitable sand sources that match the existing beach material can also be difficult and environmentally sensitive.

Offshore reefs

Offshore reefs are artificial structures built in the sea at some distance from the shore. These can be constructed from concrete, rocks, or specially designed materials that encourage marine wildlife to establish new habitats.

The key advantage of offshore reefs is that they cause waves to break further from shore, significantly reducing the wave energy that reaches the coastline. They can also create new marine ecosystems and potentially offer recreational opportunities such as diving sites.

However, offshore reefs can interfere with fishing activities and boat navigation, potentially affecting local maritime industries. They are also expensive to construct and install, costing around $5,000 per metre, and may require detailed environmental impact assessments before approval.

Choosing the right approach

The selection of coastal management techniques depends on various factors including the economic value of the area being protected, available funding, environmental concerns, and community preferences. Coastal managers often use a combination of hard and soft engineering methods, selecting the most appropriate technique for each specific location based on its unique challenges and requirements.