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Beaches And Dunes

What are they?

A beach is an area along the coastline that has a build-up of sand. Most of the Adelaide coastline is made up of beaches, which are shaped by a wave action called longshore drift. This process moves sand northwards along the coast. At the northern end of Adelaide 's coastline, beaches are generally wide and sandy, while at the southern end they are generally narrow and rocky.

Sand dunes are areas where sand has accumulated to form a series of ridges. A healthy sand dune system has at least three dunes and swales, and a range of dune plants. A swale is the lowest point in the dune.

dunesketch

Sand dunes are important because they:

  • Protect areas behind the dunes from storms and large waves.
  • Store sand for beaches that have had sand stripped away by waves.
  • Provide shelter, food and breeding sites for many birds, reptiles and insects.

 

Did you know?

Beach sand comes from many sources, including creeks and rivers, cliff faces, sand bars, seagrass and shells. Sand is also supplied to our beaches artificially. We move sand between beaches or pump it from the sea onto the beach because the changes we’ve made to the coast mean there is not enough sand available to maintain them naturally. Much of the sand in the coastal system is trapped under roads and houses or held back by walls.

sandcarting

 

Sand carting at Glenelg

What lives there?

Sandy beaches are home to a surprising number of animals that visitors usually don’t see because they are microscopic or hiding. Creatures that burrow into the sand include crabs, marine worms, copepods, amphipods, nematodes and molluscs (see photo). Washed up seagrass and seaweed is also a habitat for beach creatures and a temporary shelter for animals, such as sea stars, starfish and urchins, that have been washed ashore.

Sand dunes, and the plants which grow on them, provide food, shelter and shade for a range of insects, reptiles, birds and mammals.

bivalves

 

Bivalves sieved from a sandy beach

Where are these habitats?

Beaches are easy to find along Adelaide ’s coastline, as you may know from swimming in the warmer months. Some of the most popular swimming beaches are Brighton , West Beach and Glenelg. Sand dunes are harder to find. There are remnant sand dunes at Tennyson, West Beach and Osborne. Many councils, such as Holdfast Bay , are now actively re-establishing sand dunes at beaches such as Brighton .

Click here for a Sandy Beaches fact sheet (PDF 243kb)

Click here for a Sand Dunes fact sheet (PDF 266kb)