Correct Option
The correct option is (b).
Explanation
The flow characteristics and channel patterns of rivers in the Northern Plains are primarily determined by the gradient of the terrain. In their mature and old stages, rivers flowing through flat plains with low gradients exhibit reduced velocity, leading to deposition and the formation of meanders.
Statement-wise Analysis
- Statement 1 is Incorrect. The Indus plain is a vast, flat depositional surface formed by the alluvial deposits of the Indus and its tributaries. It does not possess a steep slope; on the contrary, it is characterized by an extremely gentle gradient, similar to the Ganga plain.
- Statement 2 is Correct. The Ganga plain has an extremely gentle slope. Ambala, which is located on the water divide between the Indus and the Ganga river systems, has an elevation of approximately 291 meters above mean sea level. The river flows towards the Sunderbans, which is near sea level, covering a distance of about 1,800 km. This results in a gradient drop of roughly 300 meters over 1,800 km, or approximately one meter for every 6 km. This negligible slope causes the river to flow sluggishly and develop large meanders.
Key Takeaway: The meandering nature of the Ganga in the plains is a direct geographical consequence of its extremely low gradient (1 meter drop per 6 km), which promotes lateral erosion over vertical downcutting.