Mound or ridge of sand deposited by the wind, capable of movement when unvegetated. Dune building can be augmented by sand fencing, planting beach grass, or planting native plants.
This article was written by students in a grade school class in Australia.
Dunes form where 'constructive' waves encourage the accumulation of sand, and where onshore winds blow this sand inland. Dune formation is promoted by the presence of obstacles such as vegetation, pebbles and soils to trap the moving sand grains. As the sand grains get trapped they start to accumulate, starting dune formation.
Factors which affect the formation of coastal dunes include:
- Beach storm erosion
- Reduced coastal environment
- Flooding due to storm waves surge
- Sand movement
- Landslides and rock fall.
Dunes are a protection against the force of the waves and winds. They supply sand to the beach to prevent damage and erosion. Damage or reduction of vegetation within the dunes makes the sand dunes vulnerable to coastal winds and waves which results in sand dune drifts. Dune restoration can help eroded or degraded dunes by rebuilding through techniques such as fencing, sand fill and re-vegetation.
Additional References on Dunes
The Dune Book (North Carolina Sea Grant, 2003)
Dune Protection and Improvement Manual for the Texas Gulf Coast, Fifth Edition (Texas General Land Office)