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• Coastlines are being eroded by waves and the weather.
• Coastlines need to be managed because they are often used by humans for purposes such as housing.
• To protect the coast from erosion, we can use hard engineering strategies (building man-made structures such as sea walls) and soft engineering strategies (using natural processes such as beach nourishment).

Play a Planet Planners mission to help locals, tourists, plants and animals deal with erosion.

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Coastlines need to be managed to prevent natural processes, such as erosion and flooding, destroying vulnerable areas of the coast. Often the coastline is used by people for homes, agriculture, industry, tourism or other businesses. In addition, there are many coastal areas which are sites of natural beauty or are of special scientific interest. A failure to prevent erosion and flooding can lead to a loss of life or property.

With climate change leading to rising sea levels and more extreme weather, the coastline may become increasingly vulnerable.

Before taking any decision to protect a section of coast, local authorities will undertake a cost-benefit analysis. If the cost of protecting the land outweighs the benefit, then the land may be left for nature to take its course.

One coastline in the UK that suffers from erosion is the Holderness Coast in Yorkshire. The soft rock of the coastline is the fastest eroding coastline in Europe with some areas suffering from ten metres of erosion a year. Some parts of the Holderness coastline, such as the coastal towns Bridlington and Withernsea, are being protected from coastal erosion. Other sections have been designated as 'do nothing' areas and so they have no sea defences at all.

Play a Planet Planners mission to help save tourist areas from the effects of erosion.

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There are different options available for managing coastlines:

• hard engineering, where man-made structures such as groynes are built to stop longshore drift
• soft engineering, where more natural processes are used, such as regenerating sand dunes

Hard engineering strategies involve building man-made structures to defend the coast. Here are some examples:

Sea walls

Sea walls are concrete barriers built along the seafront that deflect waves back to sea. They also protect the land behind them from flooding.

Advantages - Very hardwearing, protect against erosion and flooding.

Disadvantages - Usually the most expensive option, they can sometimes be eroded themselves and so need maintenance.

Rock armour

Large rocks or boulders can be placed in front of a cliff to absorb the energy of the waves and slow the rate of erosion.

Advantages - A fairly cheap defence, the rocks look more natural than a concrete wall.

Disadvantages - Strong waves can cause the boulders to move meaning they need to be replaced.

Groynes

Wooden or rock barriers built at right angles to the beach. These trap sediment to build up a larger beach, which absorbs wave energy and reduces erosion. This has been successful in protecting the town of Mappleton on the Holderness Coast. However, the groynes have prevented sediment from moving southwards along the coastline, which has led to an increase in erosion elsewhere.

Advantages - Builds up a large beach which, as well as providing protection from erosion, can attract tourists.

Disadvantages - As groynes stop the movement of sediment they can cause sediment starvation further down the coast, leading to further erosion there.

Gabions

Gabions are cages of rocks. These provide a barrier between the sea and the land, reducing erosion and providing stability to the shoreline.

Advantages - Cheap and easy to build.

Disadvantages - Some people find gabions ugly as they don’t look as natural as other defences, especially as the wire cage starts to rust.

Soft engineering options use natural processes to protect the coast. Here are some examples:

Beach nourishment

Sand or shingle is placed on a beach to create a higher and wider beach. This will absorb more wave energy and protect the land behind.

Advantages - The beach looks natural and it can help to attract more tourists.

Disadvantages - The new sand and shingle wash away and so the process needs to be repeated over time.

Dune regeneration

Sand dunes provide natural protection against storms and flooding. By planting marram grass in the area, sand is trapped and large dunes form, providing a barrier between the sea and the land.

Advantages - Sand dunes provide natural protection from the sea. It is relatively cheap to carry out planting projects.

Disadvantages - There is no guarantee that the sand dunes will stay in place. They may be damaged by storms or by people walking over them.

Managed retreat

Some areas of low-value land are allowed to flood creating a salt marsh. This area of land acts as a buffer.

Advantages - Salt marshes provide natural protection from the sea and they are an important habitat for wildlife.

Disadvantages - Land is sometimes lost to the sea and so compensation has to be paid to the landowners.

Play a Planet Planners mission to help balance people's needs with the defence of the coast.

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