Dr Bayes Ahmed (UCL Risk and Disaster Reduction) argues that South Asia is entering a regional dam-building race – without the institutions needed to share its rivers. Bangladesh has just approved one of the largest river engineering projects its history: the Padma Barrage, a vast river-control project intended to restore water in the country’s drought-prone southwest. It comes at a dangerous moment for South Asia’s rivers. China is building the world’s largest hydropower dam upstream on the