The French capital, known for its grand architecture and the picturesque river Seine, was hit by a deluge of rain during the Great Flood of Paris in 1910. It resulted in the Seine levels rising to an alarming 8.62 meters, flooding large parts of the city. Despite the engineering prowess of the era, Paris struggled for weeks to regain normalcy, grappling with waterlogged streets, compromised transportation, and damaged properties. The event left an indelible mark on the city's psyche, a stark reminder of the devastation an uncontrolled Nature could unleash upon a bustling metropolis.
Fast forward to the present, a similar tale is unfolding across cities in North India, though due to different reasons. These cities, burgeoning under rapid urbanization and population explosion, are witnessing a crisis each monsoon season, owing to unprecedented rainfall. The existing urban infrastructure, largely unprepared and insufficient to handle such extreme weather events, caves under pressure. Poor drainage, the rapid and unplanned urban sprawl, and the lack of effective flood control measures turn every downpour into an urban nightmare.
Streets turn into rivers, homes into islands, and daily life comes to a standstill as Indian cities like Delhi, Gurugram, and Mumbai grapple with inundation. The plight of these cities echoes the distress of the Parisians more than a century ago, underlining the persistent global challenge of urban flooding. It underscores an urgent need to rethink urban planning, embrace sustainable development, and invest in resilient infrastructure that can effectively combat the increasing threat of urban floods.
In the face of climate change and erratic weather patterns, lessons from the past and the challenges of the present must pave the way for a future where cities are equipped to deal with the worst of nature's furies, instead of succumbing to them. Urban flooding, a multifaceted issue brought about by the inconsistent nature of city landscapes, has been a burgeoning global problem for the past few decades. Two major contributors fuel this upsurge - urbanisation, an inherent factor, and climate change, an external force. However, it's crucial to note that urban development plays a more substantial role in exacerbating local urban flooding compared to climate change.
A multitude of triggers can set off urban floods in Indian cities, including the overflow of nearby rivers, reservoir/barrage malfunctions, incessant rainfall upstream, encroachment of stormwater drains, and breakdowns of the drainage infrastructure. This issue is further magnified by hasty and unregulated urban development, which substitutes absorbent earth with impervious concrete, obstructing natural water routes.
Urbanisation and economic growth in major Indian cities like Delhi, Mumbai, Chennai, Calcutta, Bangalore, and Hyderabad have faced their fair share of challenges, chief among them being inadequate stormwater management. The overuse of concrete in these cities prevents rainwater from soaking into the ground, leading to standing water, soil erosion, and property damage. To solve these problems, it is critical to have political commitment and engineering expertise to deal with matters such as illegal construction, diminishing natural water channels, and changing land uses.
Bengaluru, for example, has acknowledged that it needs to significantly expand its stormwater drains to reduce the risk of urban flooding. The city is considering the addition of an extra 600 km of drains and is exploring natural solutions, such as the 'sponge city' concept.
Other notable contributors to this issue include ineffective drainage systems, lax waste management, geographical conditions, and the invasion of crucial natural barriers like mangrove forests.
Of particular note are India's coastal cities, which encounter distinctive flood-related risks. They suffer from both river and urban floods, while also grappling with the effects of coastal flooding and storm surges. The after-effects of such floods are immense, displacing populations, damaging infrastructure, causing transport chaos, and triggering economic setbacks.
Addressing urban flooding in India requires a comprehensive strategy. Critical components of this include refining the management of stormwater runoff by designing and maintaining proficient drainage systems. It's equally essential to champion sustainable urban development which conserves open spaces and natural barriers. A stronger focus on waste management is essential, with residents urged to discard waste responsibly, especially plastic, to prevent drainage obstruction.
Urban planning and the evolution of infrastructure should keep pace with projected population growth. An infrastructure capable of withstanding extreme weather conditions is an urgent requirement. Measures like rainwater harvesting and optimizing the use of weather forecasts are important aspects of this strategy. Finally, community-driven initiatives and public involvement are invaluable in executing these strategies. Combined, these actions can significantly alleviate the devastating impacts of urban flooding during India's monsoon season.
Recent studies have highlighted the need for a systematic examination of global versus regional drivers of trends in Indian rainfall extremes to inform flood hazard preparedness and water resource management. One approach is using GIS-based multi-criteria analysis to identify potential flood hazard areas, incorporating criteria such as flow accumulation, elevation, land use, and slope. Additionally, an integrated approach that combines remote sensing, GIS, and field surveys can help identify and predict flood-prone areas, analyse the causes of flooding, and support existing forecasting models.
Other strategies include the implementation of stormwater infiltration facilities and green roofs to manage stormwater runoff and enhance rainfall absorption. However, challenges such as limited capacity for planning and implementation, unplanned drainage systems, and the need for sustainable drainage practices are obstacles to developing urban flood resilience in India. Addressing these challenges and adopting comprehensive and integrated approaches are crucial for effective urban flood risk management in India.
Around the globe, cities are rethinking their approach to water management, recognizing that traditional quick-drainage methods are making our cities more prone to serious floods. Instead, they're now focusing on a technique that encourages the slow movement, spreading, and storage of rainfall, which is proving to be a more effective way of managing heavy rain and preventing areas from becoming waterlogged.
In managing the threat of urban flooding, it's also crucial to take into account local terrains and set up real-time monitoring systems for weather and stormwater drains. Implementing these steps can significantly improve a city's ability to withstand flooding.
A comprehensive approach to urban planning in India must adopt a broad view of stormwater and drainage management. This approach should include innovative strategies such as the 'sponge city' concept, digital monitoring systems, and rainwater collection from roofs. A combination of these approaches, backed by strong political support at the state level and the right engineering solutions, can effectively tackle the complicated issue of urban flooding in India.
Confronting the intricate challenge of urban flooding in India, a country in the throes of swift urbanisation and climate change, calls for a blend of innovation, integration, and a holistic perspective. As philosopher Albert Einstein wisely articulated, "We cannot solve our problems with the same thinking we used when we created them."
Harnessing cutting-edge technologies, adopting stringent urban planning measures, and encouraging active community participation is pivotal in achieving our objective of crafting resilient cities capable of withstanding nature's most relentless onslaughts. In an era marked by the increasing unpredictability of weather patterns, the path to such resilience is not just a pressing requirement but an existential necessity. This ensures our cities are not mere survivors in the face of adversity, but thriving communities, continuing to prosper amidst challenges.
Bibek Debroy is the Chairman, Economic Advisory Council to the Prime Minister (EAC-PM) & Aditya Sinha is Additional Private Secretary (Policy & Research), EAC-PM.
Disclaimer: These are the personal opinions of the author.