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Where are the coastal defences?

Scarborough is a town on the North Sea coast of North Yorkshire, England with a population of around 50,000. Scarborough is the largest holiday resort on the Yorkshire coast.

The most striking feature of the town's geography is a headland pointing eastward into the North Sea which separates the sea front into a North Bay and a South Bay.

In 1896 the Council decided to link the two bays by the construction of a 1200 metre link road to be known as Marine Drive. At the time there was much support for the project, not only for the commercial advantages but also due to the pressing need to prevent coastal erosion.

When were the coastal defences built?

The 22 month coastal protection project began in April 2002. It arose from a Coastal Defence Strategy undertaken by Scarborough Borough Council in 1998, which identified a prioritised action plan for the whole of the town’s coastal frontage.

Why were the coastal defences built?

Severe wave overtopping from the near vertical sea walls causes regular closure of Marine Drive, usually more than 35 times a year. This has a economic impact for local businesses.

Renewed cliff foot erosion would increase the risk from landslides on the headland. Landslides from the Scarborough Castle Headland have been common through history and indeed over a period of 700 years the site of Scarborough Castle had dwindled from 60 acres to 16 acres due to erosion.

Threat to public safety and assets. The resulting threat to public safety and protected assets (estimated at approximately £100m) was considerable.

What coastal defences were built?

• £25.7 million coastal protection project.
• 11,000 metres square of concrete ‘boardwalk’ style paving has been provided to form a new promenade around Marine Drive.
• A 1 metre high concrete wave return wall has been cast along the frontage.
• Scarborough Council determined that the provision of an Accropode revetment with a 1m high wave return wall would allow for overtopping to be reduced significantly, thus significantly reducing the risk of damage to Marine Drive and greatly enhancing the safety of its users.

• Accropodes – interlocking concrete rock armour units.
• Up to 4,000 are being were to protect the East Pier and Castle Headland. They were pre-cast in Sunderland, then brought to Scarborough in barge loads of 40 at a time.
• Each Accropode weighs about 15 tonnes.
• These interlocking units are lighter than rip-rap and therefore can be used at a steeper gradient. Accropodes also have a greater percentage of voids and for given wave conditions overtopping is less.
• They have a stronger visual impact than rock armour but this is significantly offset by the smaller profile of an Accropode armoured bund.
• Lower cost than rip-rap.
• Greater stability and lower maintenance.
• Design life of at least 50 years.

• 280,000 tonnes of granite from Larvik, Norway to act as rock armour (rip-rap).

East Pier, Castle Headland and the Holms Coastal Protection Works Booklet

Who built the coast defences and who paid for them?

Review

Using the resources above produce an outline of an answer to the following exam question:

What strategies can be put in place to control the impact of wave erosion upon human activity. You should give examples from an area you have studied. [8 Marks]