The Ganges and Brahmaputra rivers both have their source in the Himalayas where glacier melt water is an important source for the headwaters of the river. The whole drainage basin is just over 1.6 million km2 (0.6 million miles2). The Brahmaputra river originates in eastern Tibet where as the Ganges river’s source is in the West by the Tibet/India border and flows south east across India to join the Brahmaputra river in Bangladesh. From here the Ganges-Brahmaputra River flows to the Bay of Bengal where it forms the Ganges Delta. This delta is one of the largest in the world and has the highest population density of any delta.
The world’s higher population density is supported by the Ganges and Brahmaputra rivers making them important to the survival of millions of people.