URBAN FLOODING
Urban flooding has emerged as a serious challenge in India, with many states witnessing extreme rainfall events exceeding 20% of normal averages this monsoon season.
The increasing intensity of these weather patterns is largely due to the ongoing climate crisis. Over 64% of Indian sub-districts have experienced a rise in heavy rainfall days over the last decade, compared to the previous 30 years.
Alongside climate change, human activities such as unplanned urbanization, inadequate waste management, and poor drainage systems have exacerbated the situation, causing severe waterlogging and surface runoff in urban areas.
What is Urban Flooding?
- Urban flooding occurs when land or property in cities and towns becomes submerged due to heavy rains, overflowing rivers, or poor drainage systems.
- Unlike rural floods, urban flooding is worsened by impermeable surfaces like roads and buildings, which prevent water from soaking into the ground.
- This leads to waterlogging, disrupts transportation, damages urban infrastructure, and poses significant health risks.
Factors Contributing to Urban Flooding in Indian Cities
Increased Impermeable Surfaces:
- Rapid urbanization has led to extensive concretization, replacing natural permeable surfaces with impervious ones.
- This reduces the land’s ability to absorb water, leading to excessive runoff during heavy rains.
- For example, Mumbai’s built-up area increased by nearly 100% over the past 27 years, drastically increasing flood risk.
Outdated Drainage Systems:
- Many Indian cities use old drainage systems designed decades ago, which are now inadequate for current population levels and rainfall intensities.
- These systems often get clogged by waste, further reducing their capacity to handle rainfall.
- Delhi, for instance, still uses a drainage system from 1976, despite a population increase of four times since then.
Rising Extreme Weather Events:
- Climate change has intensified rainfall patterns, leading to more frequent extreme weather events.
- Indian cities now experience unprecedented downpours, overwhelming their outdated infrastructure.
- Chennai’s November 2015 rainfall reached 1,218.6 mm, the highest in over 100 years, leading to massive flooding.
Loss of Natural Water Bodies:
- Urbanization has caused the destruction of lakes, ponds, and wetlands, which traditionally acted as natural buffers against flooding.
- Bengaluru has lost 79% of its water bodies due to unchecked construction, reducing its capacity to handle excess rainfall.
Unplanned Development:
- Construction in ecologically sensitive areas like hillsides has disrupted natural drainage patterns and increased flood risks.
- The 2013 Kedarnath floods, worsened by unplanned development, led to widespread destruction, demonstrating the dangers of encroaching on sensitive zones.
Inadequate Waste Management:
- Poor solid waste management in cities leads to clogged drains, further aggravating flooding.
- India generates 1.5 lakh tonnes of municipal solid waste daily, but only a fraction is properly managed.
- This mismanagement causes drains to overflow, particularly during monsoons, contributing to urban flooding.
Coastal Vulnerability:
- Coastal cities like Mumbai, Chennai, and Kolkata are particularly vulnerable due to rising sea levels and land subsidence, both worsened by climate change.
- It is projected that by 2050, Mumbai could see a 25% increase in flash floods and a 0.5-meter rise in sea level.
Major Impacts of Urban Flooding
Economic Losses:
- Urban floods cause significant financial damage by disrupting businesses and damaging infrastructure.
- For example, the 2005 Mumbai floods caused an estimated USD 2 billion in losses, while the 2015 Chennai floods resulted in USD 3 billion in damages.
Health Risks:
- Floodwaters often mix with sewage, leading to outbreaks of waterborne diseases such as malaria and leptospirosis.
- For example, Patna experienced severe malaria outbreaks following the 2019 floods.
Transportation Disruption:
- Urban flooding paralyzes transportation systems, causing immense economic losses due to reduced productivity.
- During the 2022 Bengaluru floods, IT companies reported daily losses of ₹225 crore as employees were unable to commute to work.
Impact on Urban Poor:
- Low-income communities living in flood-prone areas, such as slums, are disproportionately affected.
- Slum dwellers in Mumbai, comprising about 41% of the population, were severely impacted by the 2005 floods, and many continue to face long-term setbacks.
Psychological Impact:
- Recurring floods take a psychological toll, with many affected individuals experiencing stress and trauma.
- Rates of Post-Traumatic Stress Disorder (PTSD) can be as high as 30-40% among flood survivors.
Damage to Cultural Heritage:
- Flooding also threatens cultural heritage sites. For instance, the 2019 floods in Hampi, a UNESCO World Heritage site, caused significant damage.
Government Initiatives to Address Urban Flooding
- Jal Shakti Abhiyan (JSA): Focuses on water conservation and rainwater harvesting.
- Amrit Sarovar Mission: Aims to rejuvenate water bodies.
- Atal Bhujal Yojana: Works towards groundwater management.
- Atal Mission for Rejuvenation and Urban Transformation (AMRUT) 2.0: Focuses on urban water management.
Solutions to Enhance Flood Resilience in Indian Cities
Sponge City Model:
- This concept emphasizes creating permeable surfaces and rain gardens to absorb and manage rainwater naturally.
- Cities like China have seen positive results, with sponge city areas retaining 70-90% of annual rainwater.
Smart Stormwater Management:
- The use of IoT technology to monitor and predict flood risks can improve urban flood management.
- Singapore’s Smart Water Assessment Network (SWAN) is an example of such a system.
Urban Wetland Restoration:
- Restoring wetlands can help absorb excess water during heavy rains, reducing flood risks.
- Kolkata’s wetlands, for instance, treat wastewater and protect against flooding.
Flood-Resilient Architecture:
- Incorporating flood-adaptive designs such as elevated structures and green buildings can reduce damage from floods.
Community-Led Initiatives:
- Engaging communities in micro-level interventions, such as rainwater harvesting, can build local resilience to floods.
Conclusion
Urban flooding in India is a growing challenge due to rapid urbanization, climate change, and inadequate infrastructure. By adopting solutions like the sponge city model, smart stormwater systems, and community-led initiatives, Indian cities can significantly enhance their resilience to floods, protecting lives, livelihoods, and infrastructure.
Mains Question:
- Discuss the major causes of urban flooding in Indian cities, focusing on the role of rapid urbanization, climate change, and inadequate infrastructure. Suggest sustainable solutions to enhance urban flood resilience. (250 words)