Coastal erosion is a serious challenge that affects coastlines around the world, posing threats to ecosystems, infrastructure, and local communities.
Several strategies have been developed to manage and mitigate these impacts, which fall broadly into two categories:
Each approach comes with its own set of benefits and drawbacks, so they are selected based on the specific circumstances of each coastal region.
Hard engineering is the use of physical structures to manage coastal erosion and mitigate the impacts of waves. These measures offer immediate protection.
Sea walls are concrete or rock barriers that stand tall against the relentless force of waves. They provide a robust defence for coastal areas.
Here are some advantages of building sea walls:
However, sea walls also have some disadvantages:
Example of sea walls in the UK: The concrete sea walls along most of Swanage Beach in Dorset protect the cliffs from erosion but create a strong backwash that removes sediment from the beach.
Groynes are wooden or stone barriers that extend perpendicular to the coastline, interrupting longshore drift and trapping sediment.
Longshore drift is the movement of sand and stones along a coastline by wave action, which can lead to more erosion. By trapping sediment, groynes counteract this process.
They offer several advantages:
However, groynes also present a few disadvantages:
Example in the UK: The timber groynes installed on Swanage Beach have successfully reduced beach erosion but have also caused narrowing and increased erosion further along the coast.
Soft engineering uses natural processes and techniques to manage coastal erosion and maintain the delicate balance of coastal ecosystems.
This approach often works harmoniously with the interests of local communities. Also, it is much less disruptive to natural processes, compared to hard engineering techniques.
Beach nourishment involves adding sediments, such as sand and shingle, to replenish eroded beaches. It offers many advantages:
However, beach nourishment also has a few disadvantages:
Example in the UK: The replenishment of sand and shingle on Swanage Beach from dredged material in Poole Harbour widened the beach and reduced erosion. This provided increased protection to properties and cliffs.
In certain cases, allowing coastal areas to retreat naturally may be more practical. This method, known as managed retreat, accommodates erosion and gives space for the sea. It offers some unique advantages:
However, managed retreat also has a few disadvantages:
Example in the UK: The Medmerry Managed Realignment Scheme in West Sussex involved moving sea defences inland to create new intertidal habitats, allowing the coast to adapt naturally while reducing flood risk.