Floods and Their Impact: An Overview

Floods have been a prominent issue in regions like Assam, which is experiencing severe flooding. Understanding the broader causes, impact, and strategies for flood management is crucial, especially with the changing climate.

Recent Events in Assam

• Assam witnessed 58 deaths due to flooding, initially attributed to a "cloudburst" in Mon, Nagaland, which was actually heavy rainfall of 137 mm over eight to nine hours.

Understanding Floods and Flash Floods

• Floods occur due to excessive rainfall leading to water stagnation.
• Flash floods happen quickly, often in less than 6 hours, and can result from sudden rainfall or other factors like dam overflow.
• Indian Himalayan states face additional challenges from overflowing glacial lakes.
• The India Meteorological Department defines a cloudburst as rainfall exceeding 100mm per hour over a small area.

Flood Impact in India

• India is significantly impacted by floods, second only to Bangladesh globally.
• Approximately 40 million hectares are prone to flooding, affecting 18.6 million hectares annually.
• Urban areas like Chennai and Mumbai frequently experience flash floods.

Factors Contributing to Flooding

• 75% of Indian rain falls during a short monsoon season (June to September).
• Climate change increases the frequency of flash floods, with an increase in events from 132 in 2020 to 184 in 2022.

Study on Flash Floods in India

• Conducted by IIT-Gandhinagar and published in Nature Hazards.
• Flash floods are largely centered in the Himalayas, the west coast, and Central India.
• Only 25% of flash floods are caused by extreme precipitation; others result from a combination of rainfall and soil conditions.

Impact of Climate Change

• Rising temperatures lead to more intense precipitation and increased flash floods.
• Regions like the Brahmaputra, Ganga, and Krishna basins are highly vulnerable.

Strategies for Mitigating Flood Impact

• Investing in early warning systems and modernizing weather monitoring infrastructure.
• Implementing ecological solutions like restoring wetlands and reforestation.
• Mainstreaming climate resilience in policy frameworks and urban planning.
• Enhancing community-based disaster management using traditional knowledge.

Exam Context

• Preliminary questions on cloudbursts.
• Main exam questions on interlinking rivers and flood management in urban areas.