(b) Semi-Arid Transitional Plain or Rajasthan Bagar
The line dividing the Sandy Arid Plains and the Semi-Arid Transitional Plain is climatic, i.e. 25cm isohyets. The western-most belt which is ‘The Great Desert’ is covered by sand dunes which stretch from the Great Rann along the Pakistan border to Punjab. The degree and extent of sand dunes greatly influence the economic activity in this area. 63 per cent sand dune area of Rajasthan is concentrated in the desert districts of Barmer, Jaisalmer and Bikaner.
- Jaipur, Jodhpur, Nagaur, Pali, Jalore, Barmer districts covered in semi arid.
- Area – 7500 Sq. Km
- Rainfall – 20 cm
- Gullying has given rise to conglomerate landscape. Its eastern part is covered with superficial sand deposits.
Towards north lies the Shekhawati tract which is semi arid transitional plain characterized by inland drainage & stream with salt lakes. Ghaggar Plain lies in extreme north.
Semi-Arid Transitional Plain or Rajasthan Bagar divided into:
- Luni Basin
- Shekhawati Region
- Ghaggar Plain
- Nagauri Upland
1. Luni Basin: This area is locally known as Naid and is one of best alluvial plains and flood occurs during the rainy season in Luni river.
The Luni River originates from western slopes of Naga hills of Aravalli Range near Ana sagar lake, Ajmer. Barmer, Jalore, Jodhpur and Nagaur districts are part of this basin and the total Area is 34866 .4 Sq. Km.
Basin is drained by the Luni river & its tributaries Bandi, Saagi, etc. Covers the area from its source to Tilwara in Barmer where Sukari river meets it.
2. Shekhawati Region: Aravalli hills runs through this region from south to north, cutting into almost two halves and Churu, Sikar, Jhunjhunu & Nagaur districts are part of this region; the main occupation of this region is live stock, Milk production & dairy.
Topography of the Shekhawati tracts is characterized by an undulating sandy terrain traversed by longitudinal sand dunes. Kantli is the only seasonal river.
3. Ghaggar Plain: Hanumangarh & Sriganganagar districts are part of this plain. There is no stream or river except Ghaggar Nali which flows through the ancient bed of Ghaggar river which is now extinct; this region is known as Ghaggar Plain. This plain is a sandy plain interspersed with sand-dunes &small sand-hills. A large part of it is dreary & full of sand dunes. Northern part of this region is fully canalled & thus is made productive. Sand ridge dunes are found on the bank of ancient rivers height of sand ridge dunes-6 m to 30 m.
4. Nagauri Upland: Average height of this region from sea level is 300 m to 500 meter and the rainfall in this region is 25 cm in west to 50 cm in east. This region is full of sand hills & low depressions and the temperature being High, the evaporation of the saline flood water results in the deposits of the Salt & Soda in the depression.