- published: 01 Apr 2016
- views: 41821
In physical geography, a dune is a hill of sand built either by wind or water flow. Dunes occur in different forms and sizes, formed by interaction with the flow of air or water. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind. The valley or trough between dunes is called a slack. A "dune field" is an area covered by extensive sand dunes. Large dune fields are known as ergs.
Some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. In most cases the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most widely distributed dunes are those associated with coastal regions, the largest complexes of dunes are found inland in dry regions and associated with ancient lake or sea beds.
Dunes also form under the action of water flow (alluvial processes), and on sand or gravel beds of rivers, estuaries and the sea-bed.
I just missed the boat
The one sailing through your heart
That unknown port
That mysterious sea
The wharf is long and lonely
The ship is out of sight
The sinking orange sun
On the whitecap waves
The rocks and sand and seaweed
The dunes and the tall grass
They say the ferry's discontinued
And I can't stay on the pier
I turn and turn