Coastlines: deposition

Many features of our coastline are created by deposition. This is when the sea drops sand, rocks and pebbles it has been carrying.

In this article you can learn:

• How deposition creates different coastal features
• What longshore drift is
• Wildlife in Forvie National Nature Reserve

This resource is suitable for Landscapes topics for primary school learners.

Join Isla and Connor as they explore features of coastal deposition along the coast around Aberdeen.

• The coast is the land along a sea. The coastline is the boundary between land and water.
• Many features of the coast are created by deposition. This happens when the sea loses energy. Materials, like sand and pebbles, are transported by the sea and dropped when the sea doesn't have enough energy to carry them.
• Material from the sea bed, like sand and pebbles, is called sediment. This is picked up, transported by movement of the sea and dropped, or deposited.
• Beaches are formed from deposits of sediment. This is why they can be found on the coast. They separate the mainland from a body of water, like a sea or loch.

Longshore drift is the name of the process where materials are moved along the coastline.

1. Waves approach the coast at an angle.
2. Swash carries sediment up the beach at an angle.
3. Backwash carries sediment down the beach with gravity – at right angles to the beach.
4. This creates a zig-zag movement of sediment along the beach.

This slideshow shows different examples of coastal deposition features like sand dunes, salt marshes and tombolos.

Forvie is one of Scotland's National Nature Reserves. A nature reserve is an area of land set aside to protect habitats and wildlife.

Forvie National Nature Reserve is known for its huge sand dunes, wide mudflats and the River Ythan. The reserve is home to many different birds and other plants and animals.

• coast - Where land meets sea. Also known as coastline.
• beach - A piece of land which separates inland area from from a body of water, like a sea or loch. Beaches are usually made up of sand.
• habitat - Where an animal or plant lives and grows.
• longshore drift - The movement of material, such as sand and stones, along a coastline caused by the movement of waves. The waves move materials along the coast in a zigzag movement.
• swash - Waves that are pushed up on to the beach by the wind at an angle.
• backwash - Waves that roll back down the natural slope of the beach towards the sea.
• deposition - When materials are dropped or left behind. When the sea loses energy, it drops the material it has been carrying.
• sand dunes - A mound or hill of sand which has been blown onto the land by the wind or waves.
• spit - An area of a beach that only joins to the main part of land at one end. They start to form where there is a change in the direction of the coastline.
• salt marsh - An area of the coast that is flooded and drained by salt water brought in by the tides. They form behind a spit when water movement slows down so more material is deposited.
• mudflat - An area of muddy coast where rivers meet the sea or ocean.

Create a leaflet about one of Scotland's coastal nature reserves.

We learned about Forvie National Nature Reserve in this article but there are many other nature reserves in Scotland.

Research a National Nature Reserve near you. Design a leaflet that would encourage people to visit and look after the reserve.

Here are some examples of nature reserves where you can find coastal deposition features.

• Tentsmuir National Nature Reserve
• Taynish National Nature Reserve
• Loch Fleet National Nature Reserve
• St Cyrus National Nature Reserve

Some ideas to get you started:

• Where is the nature reserve? Can you draw a map to show its location?
• Can you list its key features? Does it have sand dunes, salt marshes or unique wildlife?
• Find a list of Scotland's National Nature Reserves here: NatureScot - Scotland's National Nature Reserves
• If you need help making your leaflet, learn more here: How to create a leaflet