[1][2] The upper part of the gorge is also called Thak Khola after the local Thakali people who became prosperous from trans-Himalayan trade.

The Kali Gandaki river source coincides with the Tibetan border and Ganges-Brahmaputra watershed divide.

It flows through a sheer-sided, deep canyon immediately south of the Mustang capital of Lo Manthang, then widens as it approaches Kagbeni where high Himalayan ranges begin to close in.

Northern India needs water for irrigation, but the gain would perhaps be small, for the Brahmaputra in Assam would be as much diminished as the Ganges was increased.

A new road would be opened for the invasion of India from the north, and therefore on the whole it is perhaps best for all parties concerned to leave things as they are.

But the changes here indicated will some time come to pass without artificial aid, for the tentacles of the Kali Gandak are eating back northwards into the mountains much more quickly than the Tsangpo is eroding its valley.