The Beas River rises/originates from the Beas Kund near the Rohtang Pass, in the upper Himalayas.
Beas
The place where the river begins is called a source.
The 'source'.
The Yangtze river is known as the Yellow river due to the high volumes of sediment that are suspended in it.
The World Longest Rivers
What is River Surfing
The Exploitation of the Colorado River
Conflicts About the Use of the Ping River