Eventually, the river joins another river, the Ganges River, on the plains. Where the two rivers meet, the land is very fertile so good for farming.
The water is very abundant.

Them exploration of India begins with the Brahmaputra River. This river start Hight up in the Himayalayas. So the water is clear and cold as it rushes over the sharp rocks.
So the people don't be in trouble for water.

This graph shows the lowest temperature is 13c and highest temperature is 32c.
So this temperature is good for living and farming. Example Himalaya Mountains are so cold so the plants can't growing.

We have a not only good things, we have a monsoon that each summer, heavy monsoon rains add water to this part of the river. But this is a not only but things, if as river overflows, the river leaves the rich minerals it has carried down from the Himalayas in the earth of the valley.