Which of the following best explains why the Kosi River frequently changes its course across the plains of Bihar despite being a perennial Himalayan river?
It deposits heavy sediments, blocking its channel
The Kosi rises in the Himalayas of Tibet-Nepal (Mount Everest region) and enters Bihar through the Chatra Gorge before joining the Ganga near Kursela.
Because of the steep gradient in the Himalayas, the river carries an enormous silt load (about 19 crore tonnes annually — one of the heaviest in the world). On reaching the flat Bihar plains, the gradient drops sharply and the river cannot carry all this sediment, so it deposits it on the bed and banks.
The deposited sediment raises and blocks the channel, forcing the river to break its banks and shift westward or eastward to find a new path. The Kosi has shifted its course by over 120 km westward in the last 250 years, giving it the nickname "Sorrow of Bihar".
The Kosi does not originate in the Western Ghats, receives heavy monsoon rainfall in Nepal, and flows through soft alluvium — so options 1, 3 and 4 are factually wrong.
Hence, the answer is it deposits heavy sediments, blocking its channel.
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Which one of the following lakes in India has a large quantity of a substance found in the Moon?
Which is the longest tributary river in India?
‘Ong’ and ‘Tel’ are tributaries of the river ______.
Consider the following statements :
i. Alamatti dam is on the Cauveri river.
ii. Mettur dam is on the Krishna river.
iii. Gandhi Sagar Reservoir is on the Chambal river.
Which of the statement given above is/are correct ?
Charre-Marre waterfall is located in which Valley ?
