Why does the kosi river bring huge quantity of sediments from the upper reaches?

The Kosi River carries a significant quantity of sediments from its upper reaches due to its steep gradient and erosive power in the Himalayan region. As the river flows down from the mountains, it erodes the surrounding rock and soil, picking up large amounts of sediment. Additionally, the river's frequent changes in course and high discharge during monsoons contribute to its sediment load, leading to frequent flooding and deposition in the plains. This dynamic process results in the Kosi being one of the most sediment-laden rivers in the world.