BBC:
Nepal’s devastating floods have exposed a risk that does not stop at its borders.
India and Nepal share the rivers that rise in the Himalayas, but the relationship between a flood in Nepal and a disaster in India is more complicated than a simple story of water flowing downstream, say experts.
Some floods can race out of the mountains carrying enormous quantities of mud, rock and debris. Others may lose much of their force as they reach the plains, leaving behind a more conventional flood.
And whether that water becomes a disaster in India depends not only on how much rain has fallen in Nepal, but also on rainfall, river levels, embankments, drainage and development on the Indian side.
Nepal’s floods are a warning for India – not simply because water flows south across the border, but because the two countries share a vast and increasingly volatile Himalayan river system.
