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Heavy rains that lashed Pune this week not only caused widespread flooding but also raised concerns about the city’s preparedness and infrastructure capacity. Heavy rains overwhelmed Pune’s drainage system, causing widespread disruption.
PREMIUM PUNE: People look at the flooded Mutha river after heavy rains in Pune district on Thursday, July 25, 2024. (PTI)
The Pune floods were caused by sustained rains in both the city and its catchment area, and the release of water from the Khadakwasla Dam. On July 25, authorities began releasing 1,000 cubic feet per second of water to prevent overflowing, but the overflowing water, combined with saturated soil, caused severe flooding downstream. Political statements of government coordination forced the city authorities to adopt a reactive stance. As a result, around 3,000 people have been affected, with 574 people evacuated and five deaths reported so far.
“Several departments in the district are on alert and coordinating with the district administration. Necessary alerts have been issued and rescue operations are underway,” Yogesh Mukhase, director general, Pune Metropolitan Region Development Authority (PMRDA), said.
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Areas like Katraj, Balaji Nagar, Padmavati, Sahakarnagar, Kondhwa, Fatima Nagar, Wanoli and Parvati were particularly hard hit, with basements and ground floors flooded. “To mitigate the immediate flooding problem, we have deployed additional pumps to suck up water, clear blocked drainage systems and remove encroachment in riverbeds and drains,” said a disaster management official from the Pune Municipal Corporation (PMC).
Heavy rains in ghats affect Pune
In the week to July 26, Pune district recorded 156 mm of rainfall – 172 per cent excess rainfall over normal 57.4 mm. According to the India Meteorological Department (IMD), the month-end rainfall till July 26 showed 482.7 mm of rainfall – 98 per cent excess rain over normal 243.7 mm. The ghat areas near Pune received nearly 500 mm of rain. “Extremely heavy rains in the ghat areas have affected downstream areas and dam catchment areas, causing severe inundation and flooding in Pune,” said Sunil Kamble, Mumbai regional director of the IMD.
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Pune received an average of 278 mm of rainfall in July, making it the wettest month of the year. The India Meteorological Department issued an orange alert for Pune and expected rainfall to subside by the end of the month. “The recent heavy rainfall is due to active offshore depressions along the Maharashtra and Kerala coasts and a low pressure system over the northern Bay of Bengal, which has led to increased monsoon activity. Strong westerly winds over the Arabian Sea and a weakening cyclonic circulation have further strengthened the monsoon winds, resulting in very heavy rains over the ghats and moderate to heavy rains in Pune city,” Kamble added.
Root cause: Urban expansion and infrastructure strain
Experts say Pune’s topography and geology resembles a teacup with catchment areas in the Sahyadri ranges, adding to the complexity of stormwater management. Before 2012-13, the PMC area was 258 sq km. Since then, 34 villages have been added, expanding it to about 552 sq km.
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“This rapid expansion is putting strain on the existing infrastructure and administrative capacity, making it difficult to effectively manage the expanded area,” said Shrikant Gabare, an urban geomorphologist. “Administrative and infrastructural capacity that was adequate in the area earlier is now inadequate. Staff, budgets and resources have not expanded proportionately, leading to major challenges,” he added.
In June 2024, the Pune Municipal Corporation had identified 89 flood-prone areas, including key locations along the river and several villages in the district.
The Mula Mutha river marked in blue flows through the saucer-shaped Pune district (marked in yellow). Various streams in orange are connected to the ghats that surround the district. (Shrikant Gabhare) {{^userSubscribed}} {{/userSubscribed}} {{^userSubscribed}} {{/userSubscribed}}
The current storm water drainage design needs to be revisited as outfalls are overflowing and inlets are clogged with waste, explained Himanshu Kulkarni, emeritus scientist and hydrogeologist at ACWADAM. “The storm water system is designed for average conditions and not for the worst-case scenario. The narrow roads beside the flyover frequently get flooded due to excess water runoff,” he said.
According to Gabare’s study of India’s topographical maps, about 40 percent of Pune’s 3,000 streams have disappeared over the past 25 to 30 years. “This significant decline in streams has led to a reduction in drainage routes, creating additional challenges for stormwater management,” he said.
Gabale explained that while the drainage department designs storm water systems, these designs are often ignored in road projects, leading to inefficient water management and increased flooding. “There needs to be coordination between departments,” Gabale said. Currently, Pune uses cement in road development, which reflects heat and contributes to the urban heat island effect. “To mitigate this effect and improve storm water absorption, we should consider tarred roads, which absorb heat better,” he added.
Impact of dam release on Pune floods
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The recent floods in Pune have been exacerbated by unregulated and premature release of water from upstream dams. “Unregulated release of water from Khadakwasla is worsening the floods in Pune. Despite the proximity of these dams to urban areas, there is a lack of active management to prevent disasters. The suggestion that dams should not be filled with more than 50% water after a disaster highlights the reactive nature of the current policy,” said Himanshu Thakkar, coordinator of the South Asia Network on Dams, Rivers and People.
Thakkar pointed out systemic problems in dam operations across India. “There is no systematic approach and the Dam Safety Act fails to address operational issues. Dams can cause disasters even in the absence of structural failure due to unregulated release of water. There needs to be an accountable, transparent and credible mechanism for dam operations,” he said.
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Mismanagement of flood protection measures further complicates the problem. Dams theoretically reduce flooding downstream, but a lack of proper operation and monitoring negates these benefits. “There are no published standard operating procedures and rule curves for dam operation, and no research on why dams operate in a particular way during flood events,” he noted.
Riverside development
The Pune Riverbank Development Project, particularly along the Mula Mutha river, is a Rs 4,727 crore initiative by the PMC to transform the city’s riverbank into a public space. It involves construction of embankments, promenades and recreational areas aimed at revitalising the riverbank and enhancing the aesthetics of the city.
Environmental activist Sarang Yadwadkar argues that the project and the floods in Pune are man-made rather than natural disasters. Any obstruction created in the riverbed, legal or illegal, leads to flooding, he said. “The floodplain along the Mula Mutha river has not been scientifically identified, a point made by the Bombay High Court in its June 26 order seeking a fresh time-bound re-examination of the floodplain,” said Yadwadkar, a petitioner in the case.
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Most importantly, development projects along the river are causing the biggest hurdles, reducing the river’s cross-sectional area by about 45-50 per cent. “This has led to severe flooding in the upper reaches of the Mula Mutha. Three of the 11 stretches have already been affected without proper environmental clearance,” Yadwadkar said.
Addressing erosion and flood control
Encroachment into natural streams and storm water channels is a major cause of flooding in Pune. Unauthorised constructions and reduction in the width of nullahs hinder effective water management. “Encroachment into natural streams has led to reduction in these important drainage channels, creating additional challenges in storm water management,” Gabale said. Areas like Ambil Oda, Ramnadi, Bairova Nall, Vadki Nall and Bapdev Ghat are affected.
Gabale said Pune’s natural topography and the catchment areas of the Sahyadri ranges combine to form a complex drainage system, which is important for flood prevention. He highlighted that Pune has 13 urban catchments. “Urban expansion and encroachment into natural flows and storm water channels has reduced the width of nullahs, hindering water management. Storm water infrastructure is unable to handle large volumes of storm water, especially during heavy rainfall,” he added.
The main drainage basin of Pune city. (Shrikant Gavale)
Under the Unified Development and Promotion Regulation, any alterations to the river require permission, but unauthorized changes continue, resulting in repeated flooding. “Urgent action is needed to address these encroachments and restore the natural flow of the water,” Gabare added.
Pune Flood Control Strategy
Pune needs open spaces and natural sponges to absorb water to combat floods. An aquifer mapping study by ACWADAM found that less than 25 percent of the city has open space coinciding with natural recharge areas. “Drilling of aquifers and loss of soil have further reduced their absorptive capacity, exacerbating the flooding problem,” Kulkarni said.
Tucker stressed the need for a systemic review of dam operations to reduce flood risks: “All dam operations need to be reviewed, rule curves made public and backed by a legal framework that ensures proper operation. Dam management failures that contribute to flooding must be addressed with accountability measures.”
Improving storm water management is also an important step. “Apart from sewerage, improving the storm water drainage system is crucial. In many places in Pune, sewage mixes with the storm water drains and this needs to be addressed with proper desilting and maintenance,” Thakkar added.
PMC officials said a budget of Rs 979.4 crore has been approved for flood prevention under the Urban Flood Management Project, with emphasis on long-term infrastructure improvements to mitigate chronic waterlogging and make the city more resilient to extreme weather events.
With La Nina yet to set in, a prolonged monsoon is expected, with rains expected for at least another two months, making proactive measures, advance planning and a systematic approach essential to effectively manage Pune’s flood problem.
