Coasts

Scotlands Living Landscapes

• Introduction
• Evolution of the Coastline
• Coastal processes
• Historical changes
• Life on the coast
• Habitats
• Human Influences
• Conservation
• Our Heritage

Coastal processes

The changing coast

By around 5,000 years ago Scotland’s coastline looked similar to todays but, even so, things still continue to change.

Sea-level rise continues to affect the Northern and Western Isles, slowly flooding low-lying areas. Elsewhere, beaches and other non-rocky coastlines are being eroded, such as at Montrose in Angus where some sand dunes are retreating up to 4m each year. The exact opposite is occurring in other places. At Tentsmuir in Fife, some of the anti-tank defences built on the shore during the Second World War now lie over 100m inland.

Even on Scotland’s rockiest coastlines, changes are occurring. The Old Man of Hoy in Orkney, appears to symbolise permanence, yet this world famous structure was only created around 150 years ago when a rock arch linking it to the cliffs of Hoy collapsed during a storm.

The wind

The wind can have a dramatic affect on our coast, especially in dune systems. Sand dunes first started building up around the Scottish coast about 5,000 years ago. From time to time they became unstable and the wind flattened them, blowing the sand inland. At Eoligarry on Barra, coastal sand smothers the hillside 100m above sea level! This process continues today, creating great waves of bare sand which drift across the landscape.

Long-shore drift

Large volumes of sand and shingle are also being driven along and around the coast, partly by the tide but primarily by the force of the waves. This process is known as long-shore drift and it occurs wherever waves strike a beach at an angle. It is dramatically shown by shingle spits which may grow by anything from 5 to 100m each year such as at Speymouth.

Seasonal change

Even over the course of a year most beaches can change dramatically in appearance. In prolonged calm weather sand tends to collect at the top of the shore but when winter storms strike, it is often scoured away by the waves and dumped on the sea bed around or below low-water mark. This seemingly annual cycle can result in beaches rising and falling by a metre or more each year.