Article 3: How to absorb rainwater – what Indian cities need to learn
Why in news: Mumbai is witnessing severe monsoon flooding due to intense rainfall, high tides, and inadequate urban drainage, highlighting the urgent need for climate-resilient infrastructure and nature-based urban planning.
Key Details
- Severe Monsoon Impact: Heavy rainfall has caused deaths, submerged roads, flooded homes, and disrupted transport and educational institutions.
- Geographical Vulnerability: Mumbai's reclaimed land, low elevation, and loss of wetlands increase its susceptibility to urban flooding.
- Drainage Challenges: Existing storm-water drains depend on gravity, making them ineffective during high tides and intense rainfall.
- Global Solutions: China's Sponge City model and the Netherlands' blue-green infrastructure demonstrate sustainable flood-management practices.
- Need for Resilient Planning: Integrating wetlands, permeable pavements, green roofs, and water-retention systems is essential for climate-resilient urban development.
Current Flood Situation
- Heavy monsoon rainfall has caused severe flooding across Mumbai.
- At least seven people have died in the last five days.
- Roads, homes, and low-lying areas have been submerged.
- Transport services have been disrupted, delaying commuters.
- Schools and colleges have suspended classes and examinations.
- The India Meteorological Department (IMD) has forecast more heavy rainfall over the next three days, increasing flood risks.
Why Mumbai Faces Recurrent Flooding
- Mumbai was built on reclaimed land that originally consisted of seven islands.
- Large parts of the city lie only a few metres above sea level, making them highly flood-prone.
- Rapid urbanisation has destroyed creeks, wetlands, and salt pans that naturally absorbed rainwater.
- During heavy rainfall, water follows old natural drainage channels, causing repeated flooding in areas such as:
- Hindmata
- Kurla
- Sion
- Western suburbs
Limitations of Existing Flood Management
- After the 2005 Mumbai floods, authorities introduced:
- Pumping stations
- Improved weather forecasting systems
- Upgraded storm-water drainage networks
- However, these measures remain inadequate for handling short-duration, high-intensity rainfall.
- Mumbai's drainage system depends on gravity to discharge water into the sea.
- During high tide, seawater blocks drainage outlets, causing rainwater to flow back and worsen urban flooding.
Global Best Practices for Urban Flood Resilience
- China's Sponge City Programme improves water retention by:
- Installing permeable pavements
- Restoring urban wetlands
- Creating artificial lakes to store rainwater
- The Netherlands has adopted innovative solutions such as:
- Water squares that store floodwater while serving as public spaces during dry periods.
- Green roofs that absorb rainfall and reduce runoff.
- These approaches combine urban development with climate adaptation.
The Way Forward for Mumbai and Indian Cities
- Mumbai has initiated lake restoration projects, but blue-green infrastructure is still limited.
- Urban planning should integrate:
- Wetland conservation
- Permeable surfaces
- Green roofs
- Nature-based drainage systems
- Future development must balance housing, transport, and commercial growth with climate resilience.
- Building sustainable and flood-resilient cities is essential to protect lives, infrastructure, and economic activity from increasing extreme weather events.
Conclusion
Mumbai's recurring floods underline the need to shift from reactive disaster management to proactive climate-resilient urban planning. Conserving wetlands, restoring natural drainage, adopting blue-green infrastructure, and integrating flood resilience into city development are essential. Sustainable urbanisation that works with nature, rather than against it, will help Indian cities withstand the growing impacts of climate change.
Descriptive question:
Q. "Urban flooding in India is increasingly a consequence of poor urban planning rather than excessive rainfall alone." Discuss with reference to Mumbai, and suggest nature-based solutions for building climate-resilient cities. (150 words, 10 marks)
Source: The Indian Express