RAS question
The Aravallis act as a water divide between which two river systems?
Correct answer: (C) Indus (Arabian Sea) and Ganga (Bay of Bengal) systems.
The Aravalli Range acts as Rajasthan's drainage divide between the Indus-Arabian Sea side and the Ganga-Bay of Bengal river system.
Explanation
The Aravallis matter in Rajasthan geography because they split the state's drainage pattern. The Luni River and its tributaries drain the western slopes of the Aravallis and empty southwest into the Great Rann of Kutch in Gujarat, placing that side on the Arabian Sea-facing drainage. Areas east and southeast of the range are drained by the Banas and Chambal rivers, which are tributaries of the Ganges. This is the standard RAS framing: most rivers rising from the Aravallis flow eastwards, while a few, including the Luni, flow westwards. The range also separates the desert tract from the better-watered eastern plains.
Why the other options are wrong
- (A) Ganga and Brahmaputra is not the Rajasthan divide described here; eastern and southeastern Rajasthan connect to the Ganges system, with no role for the Brahmaputra.
- (B) Krishna and Godavari are Deccan river systems, whereas Rajasthan's Aravalli divide runs through the Luni on the west and Banas-Chambal-Ganges drainage on the east.
- (D) Narmada and Tapti belong to central India's drainage context, not to the Rajasthan pattern where the Aravallis separate Luni-western drainage from the Banas-Chambal-Ganges side.
Concept
This tests Rajasthan's drainage and physiographic divisions, especially how the Aravalli Range controls river direction. It recurs in RAS because the same divide explains desert Rajasthan, eastern plains, and major river-system mapping in one concept.