Rajasthan ranks first in India with the viewpoint of area. So, it is natural to have landform variations here.
On the basis of land form variations, Rajasthan has been divided into the following physical regions:
1. Western Deserted Region
2. Aravalli Mountain Region
3. Eastern Plains
4. South – Eastern Plateau Region
Western Deserted Region: It is the largest physical region of Rajasthan, which lies from Aravalli mountain range to the west of Rajasthan. Its height is 60 meters to 360 meters from sea level.
Origin of Western Deserted Region: The formation of desert region in Rajasthan is considered to be done by the deposited silt in Tethys Geocycline. Due to excessive temperature and pressure over these geocyclines of Tethys, it turned into a desert.
Extension of Deserted Area: The extension of this deserted region of Rajasthan is mainly found in Ganganagar, Hanumangarh, Jhunjhunu, Sikar, Churu, Bikaner, Nagaur, Jodhpur, Jaisalmer, Barmer, Jalore, and Sirohi districts.
Division of Deserted Region of Rajasthan: On the basis of ground variation, this driest part of Rajasthan has been divided into four parts:
1. Sandy Dry plains
2. Luni Basin
3. Inland Drainage plains
4. Plains of Ghagghar.
1. Sandy Dry Plains: It is a dry deserted plain region which is situated in the west of 25 cm Isohyet of the state. The districts of Jaisalmer, Barmer, Bikaner, Jodhpur, Nagaur and Churu are included in this region.
2. Luni Basin: This basin is located in the South-west part of Aravalli between the Isohyet line of 25 cm to 50 cm. The extension of this area is in southern Jodhpur, Pali, Jalore and western Sirohi. Pachpadra is the main saline water area of this region.
3. Inland Drainage plains: It is also known as Shekhavati region. The extension of this semi-dry region is in Jhunjhunu, Sikar, and the Northern part of Nagaur. It is an area of inland drainage system. Most of the Barkhans (sandy dunes) are found in this part. In this region, the rivers and drains disappear after covering a little distance.
4. Plain of Ghaghar: It is the northern part of desert which is extended in the districts of Ganganagar and Hanumangarh. River Ghagghar is a part of Inland drainage system. The dried-up tributaries and sub rivers of Ghagghar are considered the part of River Saraswati which originated from the Himalayas. Intensive farming is practiced in this region with the help of irrigation obtained from Indira Gandhi and Gang canals.
