Due to heavy rainfall in the Himalayan and other watersheds of the eastern
India region, Assam is endowed with extensive river system consisting
of the Brahmaputra, the Kusiyara and the Barak and their tributaries.
All the rivers in Assam are liable to floods, mainly because they receive
heavy rainfall within a short time. These rivers are in their early stage
of maturity and are very active agents of erosion. The river waters collect
a tremendous amount of silt and other debris and raise the level of the
river beds. Therefore, it becomes impossible for the main channel to cope
with the vast volume of water received during the rains.