By Ritambhara
Visvesvaraya’s Hyderabad flood plan, prepared in 1909, set out to protect the city by storing the Musi river’s floodwater in reservoirs upstream. The two lakes built from it, Osman Sagar and Himayat Sagar, still lie on the outskirts of the city.
Mokshagundam Visvesvaraya was born in 1861 at Muddenahalli, in the princely state of Mysore, and trained as a civil engineer in Pune. He joined the Bombay Public Works Department in 1885 and spent more than two decades there. In 1903 he designed and patented automatic floodgates for the Khadakwasla reservoir near Pune. The gates opened on their own when the water rose past a set level, so the reservoir could store more.
The flood of 1908
In late September 1908, days of heavy rain swelled the Musi until it broke into Hyderabad. Estimates of the dead range from several thousand to more than 15,000. Nearly 19,000 houses collapsed, and tens of thousands of people lost their homes. Visvesvaraya found that the bursting of irrigation tanks in the catchment had made the flood worse. Their earthen walls gave way under the rain and released their stored water into the river.
Storage above the city
The Nizam’s government engaged him as its consulting engineer, and he reached Hyderabad in April 1909. John Law’s Modern Hyderabad, published in 1914, records his conclusion: “the immunity of Hyderabad city from flood must come from the construction of flood catchment areas” in the basin above the city. The plan proposed two reservoirs a few miles upstream. It also called for an underground drainage system inside the city.
Osman Sagar, across the Musi, was completed in 1920. Himayat Sagar, on its tributary the Esi, followed in 1927. Law noted that the scheme had gained a second purpose during planning, as a source of drinking water for Hyderabad and Secunderabad. The two lakes supplied the city’s taps until the late 1990s and early 2000s, according to The News Minute in 2019.
What the plan depends on
The design treats the catchment as part of the city’s flood defence. The reservoirs absorb the peak of a storm, but the tanks and channels that feed them also have to keep their storage and their banks. Visvesvaraya’s own account of 1908 shows what happens when small tanks fail together. Each breach adds a burst of water to a river already in flood.
That dependence now meets a national problem. India’s first census of water bodies, released by the Ministry of Jal Shakti in 2023, counted 24,24,540 ponds, tanks, lakes and other water bodies across the country. Of these, 38,496, or 1.6 per cent, were recorded as encroached.
Visvesvaraya’s plan rested on a plain hydrological point. A city is only as safe from floods as the land that drains into it. His reservoirs did their work because the basin above them was kept as storage. The work asks cities today to protect their tanks and catchments with the same seriousness they give to dams and drains.
