115 years ago

The first warning came at 2am on 28 September 1908. Musi, the river that flows through the ancient Indian city of Hyderabad, was rising dangerously. In just 48 hours, local stations recorded 18.9in of rainfall. One after the other, the city’s irrigation water tanks gave way as the river rose 60ft and flowed through the streets, leaving destruction in its wake. Once the water retreated, 50,000 houses, four bridges and a hospital were gone, and more than 15,000 people had drowned or been washed away. 

When the rain stopped, Hyderabad began to rebuild. The authorities enlisted the help of famed engineer Sir Mokshagundam Visvesvaraya, known as Sir MV, to oversee the works. Sir MV concluded that the best way to prevent floods would be to store the water that exceeded the river’s carrying capacity. He designed two large storage reservoirs, each located six and eight miles above the city, with a 20,389...