RAS question
The Eastern Plains of Rajasthan are primarily formed by the alluvial deposits of which river systems?
Correct answer: (C) Chambal and Banas.
Rajasthan's Eastern Plains are chiefly formed by alluvial deposits laid down by the Chambal and Banas river systems.
Explanation
The Eastern Plains should be read as a drainage-and-sediment feature, not just a list of districts. The Chambal and Banas systems are the main builders of these plains, which extend across parts of Jaipur, Tonk, Sawai Madhopur, Karauli, Dholpur and Bharatpur. The Rajasthan State Ground Water Atlas supports this logic: it describes the north-eastern plains as areas formed by large east-flowing rivers and their sediments, and notes that south and eastern Rajasthan have developed river systems including Banas, Chambal and Banganga. So, among the options, Chambal and Banas are the pair that directly matches the alluvial Eastern Plains context.
Why the other options are wrong
- (A) Luni and Sukri belong to western Rajasthan's drainage setting, so they do not explain the alluvial build-up of the Eastern Plains.
- (B) Mahi and Sabarmati do not match the main Eastern Plains pair; Mahi is associated with southern Rajasthan rather than the Jaipur-Tonk-Bharatpur plain belt described here.
- (D) Ghaggar and Saraswati point to the northern Ganganagar-Hanumangarh side, not to the Chambal-Banas alluvial plains of eastern Rajasthan.
Concept
This tests Rajasthan physiography through the link between river systems, alluvial deposits and regional plains. It recurs in RAS because drainage, soils and district belts are often asked together in Rajasthan Geography.