A city that knows its flood map but still drowns

On the morning of Janmashtami in August 2000, Hyderabad woke up not to celebration but to a deluge. The warning had come, like a ghost from history — the city had heard the same words on September 28, 1908, when a cyclone had turned its streets into rivers. This time, too, the rain didn’t fall; it roared as if the sky had been torn open.

“It wasn’t rain; it looked like it was pouring water,” remembers Sonu Singh, now 43, a resident of Suryanagar, Chikkadpally. At 18 then, he waded through ankle-deep water with his family of five to a half-constructed Housing Board building as the flood gushed in from RTC Crossroads, Liberty, YMCA and the Hussainsagar channel. The family watched helplessly as water swallowed their one-floor, tin-roofed home.

By night, it wasn’t just homes. The flood had reached Sundarayya Vignana Kendram, the iconic cultural centre housing a library in its cellar. “We were trying to save books by stacking them on higher shelves, but by dawn on August 24, 2000, water began flowing over the steps,” recalls Venkanna, now 45, who clung to a guava tree after gushing waters broke the wall of Sriramsagar basti, bringing down homes in its wake. “We spent three days on the terrace, waiting.”

A quarter century later, the story repeated itself. On August 7 this year, when water from Picket Nala swept through Viman Nagar, it felt like a replay of that week in 2000. Singh’s family, still in the same locality, captured on their phone the sight of water swirling outside. “Aadat hai bachpan se (we are used to it since childhood). We are not afraid of the water,” he says.

Back in 2000, Hyderabad had recorded its heaviest rain in 46 years — 263.6 millimetres on August 23 and another 246.2 millimetres the following day. The surplus nala of Hussainsagar cut through some of the densely populated working-class neighbourhoods of Ashok Nagar, where houses on its banks were the first to go under. By the time the skies cleared, dozens were dead, thousands displaced and more than 90 colonies submerged, some under 15 feet of water.

The government announced ₹2,000 ex gratia for the victims to recoup and rebuild their lives. It also commissioned the Geological Survey of India (GSI) to map vulnerable zones. “It rained for a whole day. We collected aerial photographs of the entire city and identified geological and paleochannels. Paleochannels are ancient rivers or streams that have disappeared but remain the key to understanding floods. We undertook field trips, including to the most affected areas of Moosapet and Begumpet, and submitted the report,” recalls Hari Sarvothaman, former deputy director general of GSI, who co-authored ‘Causative Factors and Suggestions to Avoid Recurrence’. A parallel study by Kirloskar Consultants was tasked with drawing up a master plan for ‘Stormwater Drainage System’ for Hyderabad city: “The scope of services includes surveys and designs of all primary drains in the municipal area”.

Hyderabad has long lived with flash floods, from the Musi river’s periodic swelling recorded by travellers like Enugula Veeraswamy in 1830 to its role during the siege of Golconda in 1687. But the one in 2000 was different — it carried a promise by officials that such devastation would never be allowed to happen again.

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The Hussainsagar, hemmed in by encroachments and drained through surplus nalas, swelled back to its ancient contours. It touched its lost shores in Brahmanwadi, Uma Nagar, Kundan Bagh, Hussain Nagar Colony, Prakash Nagar, Renuka Nagar, Patigadda and further downstream in the densely populated working-class neighbourhoods. Even the then-newly laid Necklace Road went under as waters from Raj Bhavan Road raced down M.S. Maqtha into the lake. The Hindu reported the havoc as it unfolded. Unlike the sudden Musi flood of 1908, here the waters crept up gradually, reaching their highest point at 8 a.m. on August 24. “The water reached up to that height,” says Singh, pointing to a first-floor balcony in Suryanagar.

The extent of damage was later mapped. “The flood-affected areas in Nallakunta and Barkatpura are residential colonies raised in the recent past by blocking the active channel of a prominent tributary of the Musi river. The existence of this tributary has been inferred from aerial photographs of 1964, and is brought out in the map. The heavy water, which always follows the active channel of natural surface drainage, such as the stream and tributary, was blocked by new habitats. Blockage of natural streams leads to inundation of the habitats raised along their course,” the GSI had concluded in its report.

The warning was not without context. Around the same time, an analysis by the Centre for Science and Environment revealed that Hyderabad had lost 3,245 hectares of water bodies between 1989 and 2001.

Comparison with the infamous Musi flood of 1908 was inevitable. That disaster had claimed over 15,000 lives, and spurred the construction of Osmansagar and Himayatsagar reservoirs. The Hyderabad Municipal Survey under Leonard Munn mapped the spread of the flood with a red line. But the 2000 flood was different — it was not a river overflowing but an urban calamity. It played out as five separate zones of inundation spread over a week, each triggered by the collapse of man-made systems.

That year, three tanks upstream of Hussainsagar gave way, beginning with Dulapally Cheruvu on August 26. The breach sent a wall of water into Fox Sagar Lake, swamping New Bowenpally before eventually pouring into Hussainsagar. The surge inundated the foreshore and rushed downstream along the surplus nala through Ashok Nagar, Nallakunta and Barkatpura. The Army used 40,000 sandbags and 2,000 cement bags to plug the breach at Fox Sagar.

On August 30, Durgam Cheruvu developed a breach, forcing the Army to step in and plug it before water could inundate the then sparsely populated Manikonda. Closer to the city, Shaikpet, Nadeem Colony and Langar Houz areas were marooned by the spill from Shaikpet Nala and Shah Hatim Talab. Downstream, the Hussainsagar overflow pushed water into Gandhi Nagar, Ashoknagar, Nagamiahkunta, Nallakunta and Bagh Lingampally. On the other side of the city, the newly built Mini-Tank Bund at Safilguda partially collapsed on August 26, triggering fears of a major deluge before it was controlled. And on the fringes, the overflowing Nakkavagu swamped the ICRISAT campus, where tragedy struck when a rescue vehicle overturned, killing five people.

The north to south gradient in Hyderabad is a steep one that can be gauged from the fact that the Dulapally Lake is at 1955 feet above sea level. The Fox Sagar Lake is at 1866 feet, Boinpally Lake at 1770, Picket Nala at 1737, Hussainsagar at 1688 and Lingampally Park at 1588 — a drop of 367 feet within a distance of 17 kilometres.

During the catastrophic 1908 flood, legendary civil engineer M.Visvesvaraya recorded that 221 tanks had breached the Musi catchment area. That disaster had led the princely kingdom of Nizam to construct two massive reservoirs on the river — Osmansagar and Himayatsagar — to floodproof the city. But the August 2000 flood, though less severe, should have been another turning point but it wasn’t. To this day, a heavy downpour can still bring Hyderabad to its knees, submerging neighbourhoods that are known, mapped and warned about but never secured.

The Comptroller and Auditor General (CAG), in a March 2017 report, laid bare the problem. It noted that the Greater Hyderabad Municipal Corporation (GHMC) had taken up improvement works “only on 24 (34%) out of 71 stormwater drains identified by M/s. Kirlosakar consultants”, and even these were incomplete stretches. As for the 102 drains flagged by another consultant, Voyants, the CAG said, “GHMC took up only two stormwater drains”. The report concluded that the goal of widening, deepening and constructing sidewalls to increase the carrying capacity of the nalas and limiting the risk of floods “was not achieved despite the lapse of five years”.

This failure to reimagine the city’s drainage network hit home again on October 13, 2020, when a cyclonic storm dumped 30 centimetres of rain within 24 hours, according to the India Meteorological Department. In just six hours, between noon and 6 p.m., about 14.7 centimetres of rainfall submerged large parts of the city, leaving 33 people dead. The number of casualties was higher than in August 2000, in which 21 persons were killed. The then Chief Minister of undivided Andhra Pradesh, N. Chandrababu Naidu, had pegged the losses from the 2000 floods at ₹700 crore, while in 2020, former Municipal Administration & Urban Development minister K.T. Rama Rao put the damage at ₹679 crore. Two years later, floods struck again, prompting the government to launch a Strategic Nala Development Programme. But the effort was clearly inadequate, as this year’s August 7 deluge showed, when Hyderabad’s economic and transport hub of Ameerpet was brought to a standstill.

“The situation has only worsened. There is more urbanisation and concretisation. The Kirloskar Consultants report was scientific and technically sound, but political pressure stalled its implementation. The same thing happened with the Voyants Solutions report. Most encroachments are by political players, which is the main reason why the government is unable to flood-proof the city,” says environmentalist Donthi Narasimha Reddy, who was part of the Save Musi Campaign against the Nandanvanam project in the late 1990s. The project, aimed at beautifying the Musi river and developing commercial property along the riverfront, was eventually shelved after the 2000 flood.

But between 2000 and 2024 is a long, unlearnt lesson for which Hyderabad has paid dearly. A course correction seemed to begin with the creation of the Hyderabad Disaster Management and Asset Protection Agency (HYDRAA) in July 2024.

“The water reached up to here,” recalls a worker at a car showroom in Patny Colony, pointing to the spot where floodwaters rose. Just days earlier, HYDRAA had demolished a building on the fringes of the nala, yet the showroom itself was inundated. While one staffer left by 4.30 p.m. as the downpour intensified, others had to be pulled out by emergency crews on a boat.

The constrictions in the nalas and the mushrooming of encroachments are more pronounced now than they were in 2000. Back then, the disputed site of Fatima Owais College within the Salkam Cheruvu did not exist. Today it does, a reminder of how unchecked construction has deepened the city’s vulnerabilities.

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But the threat to Hyderabad is not only from the unlearnt lesson of encroachments on nalas and lakes. It also comes from a changing rainfall pattern. In the 20th century, the city’s average annual rainfall was 768.84 millimetres. In the first 24 years of this century, it has risen to 918.45 millimetres — a near 15 centimetre annual increase on average.

Twenty-five years later, people still live in the same flood-prone colonies, just as vulnerable as before. The tragedy is not unpredictability but inevitability. Officials, engineers and residents alike know exactly which neighbourhoods will go under after every downpour triggered by a cyclonic storm in the Bay of Bengal. The question is not if Hyderabad will flood again. It is when, and how badly.