Wind is the movement of air over the earth surface.

Wind is the most effective agent of erosion, transportation and deposition in the arid regions.

There is little vegetation or moisture to bind the loose surface materials in arid regions.

As a result, wind picks up the loose surface materials and transport as well as deposits them in another place.

Wind erosion is more prominent in the desert region.

Let’s see the landforms associated with wind erosion.

The main feature formed by wind erosion is Deflation hollows.

Deflation hollows

Deflation is the lifting as well as the blowing away of loose materials from the ground.

The sand and pebbles are carried in the air or driven along the ground.

The finer dust and sand may be deposited even outside the desert margins.

Deflation results in the lowering of the land surface to create depressions which are known as deflation hollows.

These are found in non-mountainous regions.

These depressions also collect the rain water and hold this water for a long time depending on evaporation rate through rocks.

The Qattara Depression of the Sahara desert is a good example of deflation hollows.

Let’s discuss the landforms associated with wind deposition in deserts.

The main feature formed by wind deposition is Sand dunes.

Sand dunes

Dunes are the hills of sand.

They are formed by the movement of winds.

Such hillocks may be active dunes which constantly move on.

They may also be fixed or inactive dunes with rooted vegetation.

Dunes develop where the direction of wind is constant.

As a result, a gentle slope is developed in the windward side and a steep slope in the leeward side.

Dunes have heights ranging from a few meters to about 150 meters.

The common dunes are of two types: Barkhan and Seif dunes .

Barkhan or Barchan

Barkhans are the moon shaped dunes with horns.

Barkhans are the live dunes which advance steadily before winds that flow from a particular direction.

These are formed by accumulation of sand at an obstacle such as patch of grass or heap of rocks.

The wind ward side of barkhan is convex and gentle sloping while the leeward side is concave and steep.

The migration of barkhans is a threat to desert life. They sometimes encroach on an oasis and bury trees and houses.

Barkhans are found in Sahara desert of Africa.

Seifs or longitudinal dunes

Seifs are the long narrow sand-ridges which grow parallel to the direction of prevailing wind.

Seifs is an Arabic word means sword.

These dunes may extend to over a hundred miles and can attain a height of over 200 feet.

Extensive seif dunes are found in the Sahara desert, the Thar Desert and West Australian desert.

Revision

Wind is the most effective agent of erosion, transportation and deposition in the arid regions.

Deflation hollows is the lowering of the land surface which create depressions. It is a result of deflation. E.g. Qattara Depression

Dunes are the hills of sand. The common dunes are of two types: Barkhan and Seif dunes.

Barkhans are the moon shaped dunes with horns. These are found in Sahara desert of Africa.

Seifs is an Arabic word means sword. These are the long narrow sand-ridges which grow parallel to the direction of prevailing wind.

The End