Introduction

Urban flooding is significantly different from rural flooding as urbanization leads to developed catchments, which increases the flood peaks from 1.8 to 8 times and flood volumes by up to 6 times. Consequently, flooding occurs very quickly due to faster flow times (in a matter of minutes). Urban areas are densely populated and people living in vulnerable areas suffer due to flooding, sometimes resulting in loss of life. It is not only the event of flooding but the secondary effect of exposure to infection also has its toll in terms of human suffering, loss of livelihood and, in extreme cases, loss of life.

Impacts of Urban Flooding

Case Study of Chennai Urban Floods 2015

Chennai's 2015 floods were a significant case study of urban flooding, demonstrating the consequences of heavy rainfall and inadequate infrastructure in an urban setting. 

Background: 

• Heavy Rainfall: Unprecedented rainfall of over 1,049 mm hit Chennai in November-December 2015, three times the average. 
• Urban Infrastructure: Insufficient drainage worsened the impact of heavy rainfall, causing widespread flooding.

Impacts: 

• Loss of Life and Property: 300+ fatalities, thousands displaced, extensive damage to residential and commercial areas. 
• Disruption of Services: Transportation and power services severely affected, hindering mobility and causing prolonged power outages. 
• Public Health Crisis: Contaminated floodwaters increased waterborne diseases, while limited clean water access exacerbated health risks. 
• Economic Impact: Billions of dollars lost as businesses and industries faced damages and operational disruptions. 

Response and Lessons Learned: 

• Rescue and Relief Operations: Government agencies, civil society, and the army collaborated to rescue and aid affected communities. 
• Urban Planning and Infrastructure Review: Floods prompted an evaluation of Chennai's infrastructure, emphasizing improved drainage and climate-resilient practices. 
• Community Participation and Early Warning Systems: Strengthened community engagement and advanced early warning systems for better disaster preparedness.

Urban Flood Risk in India 

• There has been an increasing trend of urban flood disasters in India over the past several years whereby major cities in India have been severely affected. 
• The most notable amongst them are Hyderabad in 2000, Ahmedabad in 2001, Delhi in 2002 and 2003, Chennai in 2004, Mumbai in 2005, Surat in 2006, Kolkata in 2007, Jamshedpur in 2008, Delhi in 2009 and Guwahati and Delhi in 2010.

Droughts

• Drought, as defined by the Indian Meteorological Department (IMD), is a period characterized by long-term reduction in precipitation, coupled with other climatic factors like high winds, elevated temperatures, and low relative humidity.
• This atmospheric event can cause a widespread impact, economically and socially, particularly in agrarian countries like India.

Declaring a Drought:

• The Manual for Drought Management 2016 issued by the Ministry of Agriculture proposes two primary indicative factors for declaring a drought:

• The extent of rainfall deviation
• The subsequent dry spell

Categories of Droughts:

1. Meteorological Drought: This type of drought occurs when there is a prolonged period of below-average precipitation, leading to a shortage of water in the atmosphere, often causing dry weather conditions.
2. Hydrological Drought: Hydrological drought refers to situations where the water reserves available in sources like aquifers, lakes, and reservoirs fall below the statistical average, disrupting the water supply for human activities and ecological systems.
3. Agricultural Drought: This happens when the moisture levels in the soil drop below the level necessary for crop growth due to insufficient rainfall or water supply, leading to a significant impact on crop production and farming activities.

• However, it's worth noting that there's no universally accepted definition of drought in India, with various states adhering to their own definitions. The responsibility of declaring a region as drought-affected ultimately lies with the state government.

National Drought Management in India:

• In the realm of drought management, India has published two key documents:

1. Manual for Drought Management, 2009 by the Ministry of Agriculture.
2. Guidelines for Management of Drought, 2010 by National Disaster Management Authority.

• These documents serve as guidelines rather than enforceable rules. As per the Supreme Court ruling in Swaraj Abhiyan Vs Union of India (2016), drought falls under the definition of a "disaster" as outlined in Section 2(d) of the Disaster Management (DM) Act, 2005. 
• This necessitates the National Disaster Management Authority (NDMA) to be the primary agency responsible for drought management.

Way Forward: 

• Effective drought management in India requires efficient monitoring and early warning systems.
• Regular Drought Vulnerability and Impact Assessments are essential for a timely response.
• The Assessment of Benefits of Action or Cost of Inaction (BACI) framework for Drought Preparedness should be adopted. This suggests a shift from crisis management to a risk management approach.
• In terms of policy-making, National Drought Management Policy Guidelines, codified by the World Meteorological Organization (WMO) and the Global Water Partnership (GWP), should be incorporated.
• Preventive methods include judicious use of surface and groundwater, cloud seeding, modern micro-irrigation methods, afforestation, and the use of traditional water conservation techniques
• Mitigation measures should include contingency crop planning, relief employment programs like Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA), and crop insurance schemes like the PM Fasal Bima Yojana.

International Initiatives

• In addition to national efforts, international initiatives like the Integrated Drought Management Program (IDMP) by WMO and GWP, and the United Nations Convention to Combat Desertification (UNCCD) are critical to help nations like India develop robust and comprehensive drought management strategies.

Conclusion:

While India has made strides in drought management, there is a need for a proactive, integrated, and systematic approach involving advanced technology, traditional wisdom, and community participation. This will not only help manage droughts effectively but also help to mitigate the socio-economic impacts.