Question

how do the Himalayan rivers performed erosional activities and form depositional feature

Answer 1

The main Himalayan river systems are the Ganga, the Indus and the Brahmaputra river systems. The Himalayan rivers form large basins. Many rivers pass through the Himalayas. These deep valleys with steep rock sides were formed by the down - cutting of the river during the period of  the Himalayan uplift. They perform intense erosional activity up the streams and carry huge load of sand and silt. In the plains, they form large meanders, and a variety of depositional features like flood plains, river cliffs and levees.  
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Answer 2

Answer:

Himalayan rivers perform erosional activities as they are perennial rivers that receive water throughout the year from the source of glaciers and move downwards from the upper courses which are wider and deeper and it carries along a very huge amount of silt and sediments which later get deposited in the lower courses