The 2025 floods in Hyderabad presented an immense challenge for the Hyderabad Metropolitan Water Supply & Sewerage Board (HMWS&SB), the authority responsible for managing the crucial Osmansagar and Himayatsagar reservoirs. The deluge brought back stark memories of the devastating floods of the 1960s.
Even in the last week of July, the twin reservoirs were nearly at capacity, with inflows typically ranging between 100 and 300 cusecs. Osmansagar’s water level, for instance, was just two feet shy of its 1,790-foot full tank level (FTL), while Himayatsagar stood at 1,761 feet, nearing its 1,763-foot FTL.
However, by 10 a.m. on Friday, September 26, as the season peaked, the reservoir readings showed a dramatic tenfold increase. Osmansagar registered inflows of 3,000 cusecs and Himayatsagar 2,800 cusecs. Despite two gates being opened just two feet, outflows were limited to 460 cusecs from Osmansagar and approximately 2,000 cusecs from Himayatsagar.
Within the hour, the Board received an update: the highly anticipated inauguration of the Amberpet sewerage treatment plant by Chief Minister A. Revanth Reddy was postponed due to the relentless downpour. But the truly alarming news arrived at 12:20 p.m. – a critical flood warning. The combined discharge from both reservoirs was projected to reach a staggering 12,000 cusecs, with 5,000 cusecs from Osmansagar and 7,000 cusecs from Himayatsagar.
Fueled by ceaseless rainfall across the catchment area, including an average of 130 mm and a peak of 175 mm in Vikarabad, the reservoirs continued to swell, with flood volumes escalating rapidly.
According to HMWS&SB records, operating all 15 gates of Osmansagar to a nine-foot height, and experiencing a combined outflow exceeding 34,000 cusecs, had not occurred in six decades, since 1962 and 1965.
Later that Friday, around 5 p.m., the Board issued yet another flood warning, indicating a discharge of approximately 26,000 cusecs.
The river’s torrent showed no signs of abating. By 8 p.m., the total discharge climbed to 29,557 cusecs. A record-breaking combined inflow of 40,000 cusecs – 16,000 into Osman Sagar and 24,000 into Himayatsagar – was recorded at 10 p.m. The following morning, at 5 a.m. on Saturday, the outflows dramatically surpassed the 34,000 cusecs mark, reaching an unprecedented maximum.
Osmansagar’s gates remained fully open to their nine-foot capacity throughout Saturday. By 8 p.m., the latest figures indicated a decrease in combined inflows to roughly 12,000 cusecs, with outflows standing at 10,027 cusecs.
The Board credited the successful management of this crisis to a synergistic blend of human expertise, cutting-edge technology, and seamless coordination across various government departments.
A senior official, reviewing historical data, emphasized, ‘Such extensive gate operations haven’t been undertaken in recent memory. For context, in 2010, eight gates were raised by seven feet; in 2021, six gates by three feet; and in 2022, thirteen gates by six feet. Both 2023 and 2024 saw only six gates opened, by four and two feet respectively.’
To manage the unfolding crisis, Water Board officials diligently monitored the floodwaters approaching Osmansagar at Shankarpally bridge, located approximately 25 km upstream. Similarly, the Esi stream, a key tributary for Himayatsagar, was watched closely at Venkatapur and Amdapur villages.
This official further elaborated on the extraordinary nature of the event, stating, ‘The water level at Shankarpally bridge, which hasn’t exceeded 10 feet in the last 25 years, saw the Musi stream surge to an unprecedented 16.5 feet. Likewise, the Esi stream near Amdapur, flowing into Himayatsagar, reached an astonishing 18 feet, far surpassing its previous 25-year record of 14 feet.’