Which one of the following river basins has the highest replenishable ground water resource in the country?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → The Ganga basin
Replenishable groundwater is the water under the ground that is filled up again every year. Rain and water from rivers, canals and fields soak into the soil and reach the water table. A basin gets more of it when it is large, gets good rain and has deep, soft alluvial soil through which water soaks down easily.
Option (1) The Indus basin — Incorrect. Only a part of the Indus basin lies in India, in the north-west. Much of it gets low rainfall, so less water soaks down each year.
Option (2) The Ganga basin — Correct. It is the largest river basin of India. Its wide plains of deep alluvial soil get good monsoon rain, and many rivers and canals flow through them. So a large amount of water soaks down and fills up the groundwater every year.
Option (3) The Brahmaputra basin — Incorrect. It gets very heavy rain, but its part in India is small and mostly hilly. The plain of Assam is narrow, so its store of groundwater is much smaller.
Option (4) The Godavari basin — Incorrect. It is the largest basin of peninsular India, but it lies mostly on hard rocks. Water does not soak easily into hard rocks, so less groundwater is filled up again.
Note: This question is not from NCERT. NTA does this once in a while, but such questions are very few. Your NCERT is still enough.