Nepal, Aug. 18 -- RAJIV SINHA & SANTOSH NEPAL

The Koshi River, which drains through the highlands of Tibet and Nepal and debouches into the plains of north Bihar, is one of the most dynamic rivers in the world. The frequent shifting of the river's course in downstream plain areas can be devastating for those in its new path. Recurrent flooding and the consequent forced migration has bestowed on the river the unfortunate appellation the 'sorrow of Bihar'. Managing a river like the Koshi has for long been a nightmare for river engineers in India and Nepal. In order to develop effective river management strategies, we need to understand the structural factors that underlie the flooding.

The dynamic nature of the Koshi and the phenomenon of...