UPSC MainsGEOGRAPHY-PAPER-II202215 Marks
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Q12.

Incidence of extreme rainfall events and flash floods in recent times have led to devastating consequences for people living in low-lying areas and flood plains of the country. Discuss.

How to Approach

This question requires a multi-faceted answer focusing on the increasing frequency and intensity of extreme rainfall events and flash floods in India, their impacts on vulnerable populations, and the underlying geographical and socio-economic factors. The answer should demonstrate an understanding of hydrological cycles, climate change, and disaster management principles. Structure the answer by first defining key terms, then detailing the causes, impacts, vulnerable regions, and finally, suggesting mitigation and adaptation strategies. Include recent examples and relevant data.

Model Answer

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Introduction

India is increasingly witnessing a surge in extreme rainfall events and flash floods, deviating from the traditional monsoon patterns. These events, often characterized by short bursts of intense precipitation, have resulted in devastating consequences for communities residing in low-lying areas and floodplains. The India Meteorological Department (IMD) has reported a rise in the frequency of heavy rainfall days, exceeding 150mm, over the past few decades. This escalating trend, coupled with factors like unplanned urbanization and deforestation, poses a significant threat to India’s socio-economic fabric and necessitates a comprehensive understanding of the underlying causes and effective mitigation strategies.

Understanding the Phenomenon

Extreme Rainfall Events: These are precipitation events significantly deviating from the average, often exceeding the 90th percentile. They are characterized by high intensity and short duration. Flash Floods: These are sudden, localized floods occurring within a few hours of heavy rainfall, typically in mountainous or urban areas with poor drainage.

Causes of Increased Incidence

  • Climate Change: Rising global temperatures lead to increased evaporation and atmospheric moisture, intensifying rainfall events. The IPCC reports consistently highlight the link between climate change and extreme weather events.
  • Changing Monsoon Patterns: The Indian monsoon is becoming more erratic, with prolonged dry spells interspersed with intense rainfall periods. This is attributed to factors like the Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO).
  • Deforestation: Loss of forest cover reduces the land’s capacity to absorb rainfall, increasing surface runoff and exacerbating flood risk.
  • Urbanization & Encroachment: Rapid, unplanned urbanization leads to the loss of natural drainage systems and increased impervious surfaces, intensifying runoff. Encroachment on floodplains further increases vulnerability.
  • Himalayan Glacial Melt: Accelerated glacial melt in the Himalayas contributes to increased river flows and the risk of glacial lake outburst floods (GLOFs).

Impacts on Low-Lying Areas and Floodplains

  • Loss of Life and Property: Flash floods and extreme rainfall events cause widespread destruction of homes, infrastructure, and agricultural land, leading to significant loss of life.
  • Displacement and Migration: Affected populations are often displaced, leading to humanitarian crises and long-term migration.
  • Economic Disruption: Damage to infrastructure, crops, and livestock disrupts economic activities and leads to significant financial losses.
  • Waterborne Diseases: Flooding contaminates water sources, increasing the risk of waterborne diseases like cholera, typhoid, and leptospirosis.
  • Environmental Degradation: Floods cause soil erosion, sedimentation of rivers, and damage to ecosystems.

Vulnerable Regions in India

Several regions in India are particularly vulnerable to extreme rainfall events and flash floods:

  • North-Eastern States: Assam, Meghalaya, and Arunachal Pradesh experience frequent flooding due to high rainfall and riverine systems.
  • Himalayan Region: Uttarakhand, Himachal Pradesh, and Jammu & Kashmir are prone to flash floods and GLOFs. The 2013 Uttarakhand floods serve as a stark reminder of this vulnerability.
  • Coastal Areas: West Bengal, Odisha, Andhra Pradesh, and Tamil Nadu are vulnerable to cyclones and associated heavy rainfall and storm surges.
  • Gangetic Plains: Bihar and Uttar Pradesh are susceptible to widespread flooding due to the overflowing of rivers like the Ganga and Yamuna.
  • Urban Areas: Cities like Mumbai, Chennai, and Delhi face increasing risks of urban flooding due to inadequate drainage infrastructure.

Mitigation and Adaptation Strategies

  • Improved Flood Forecasting and Warning Systems: Investing in advanced hydrological modeling and real-time monitoring systems to provide timely warnings.
  • Structural Measures: Construction of dams, embankments, and drainage infrastructure to regulate river flows and manage runoff.
  • Non-Structural Measures: Implementing floodplain zoning regulations, promoting sustainable land use practices, and raising public awareness.
  • Reforestation and Watershed Management: Restoring forest cover and implementing watershed management practices to enhance water infiltration and reduce runoff.
  • Climate-Resilient Infrastructure: Designing infrastructure that can withstand extreme weather events.
  • Disaster Preparedness and Response: Strengthening disaster management capabilities, including evacuation plans, relief operations, and rehabilitation programs.
Region Specific Vulnerability Mitigation Measures
Uttarakhand GLOFs, Flash Floods Early warning systems, slope stabilization, glacial lake monitoring
Coastal Odisha Cyclones, Storm Surges Cyclone shelters, coastal embankments, mangrove restoration
Mumbai Urban Flooding Improved drainage systems, stormwater harvesting, floodplain zoning

Conclusion

The increasing incidence of extreme rainfall events and flash floods in India presents a significant challenge to sustainable development and human security. Addressing this requires a holistic approach that integrates climate change adaptation, disaster risk reduction, and sustainable land management practices. Investing in robust infrastructure, strengthening early warning systems, and empowering local communities are crucial steps towards building a more resilient India. A proactive and integrated strategy is essential to mitigate the devastating consequences of these events and protect vulnerable populations.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Hydrograph
A hydrograph is a graph showing the rate of flow (discharge) versus time past a specific point in a river, channel, or conduit.
Return Period
The return period in flood frequency analysis is the average interval of time within which a given flood event will be equaled or exceeded once.

Key Statistics

Between 1971 and 2019, India experienced a 20% increase in the frequency of extreme rainfall events.

Source: IMD (India Meteorological Department) Report, 2021

Economic losses due to floods in India averaged ₹1,000 crore annually between 2005 and 2015.

Source: National Disaster Management Authority (NDMA), 2017 (Knowledge Cutoff)

Examples

Chennai Floods 2015

The Chennai floods of 2015 were a result of exceptionally heavy rainfall during the northeast monsoon, exacerbated by poor drainage infrastructure and encroachment on waterways. The floods caused widespread damage and disruption, highlighting the vulnerability of urban areas to extreme rainfall.

Frequently Asked Questions

What is the role of La Niña in increasing rainfall in India?

La Niña is associated with cooler-than-average sea surface temperatures in the central and eastern equatorial Pacific Ocean. This often leads to increased monsoon rainfall in India, as it strengthens the monsoon winds and enhances atmospheric moisture.

Topics Covered

EnvironmentGeographyDisaster ManagementFloodsClimate ChangeDisaster Mitigation