Flash Floods

• Context (TH): Five soldiers, including a Junior Commissioned Officer (JCO), drowned in Flash floods near the Line of Actual Control (LAC) in the Nyoma-Chushul area in Ladakh.

About Flash Floods

• They are sudden increases in water levels that occur during or immediately after intense rainfall.
• These are highly localised events of short duration with a very high peak, typically occurring within six hours of the rainfall.

Causes of Flash Floods

• Intense Rainfall: Heavy downpours, often from thunderstorms, can overwhelm the soil’s capacity to absorb water and the drainage system’s ability to manage runoff.
• Rapid Snowmelt: A sudden increase in temperature can lead to the rapid melting of snow, causing a surge of water that can overwhelm rivers and streams.
• Dam or Levee Failures: Structural failures of dams or levees can suddenly release large volumes of water, leading to flash flooding downstream.
• Urbanisation: The proliferation of impervious surfaces like roads and buildings increases runoff, reducing the ground’s ability to absorb water and exacerbating flood risks.

Impacts of Flash Floods

• Property Damage: Homes, infrastructure, and agricultural lands can be severely damaged or destroyed.
• Economic Losses: The destruction of infrastructure and properties leads to significant economic losses and livelihood disruptions.
• Environmental Impact: Flash floods can cause soil erosion, sediment deposition, and contamination of water supplies.
• Human Lives: Flash floods can lead to loss of life due to their sudden onset and high velocity.

Mitigation Measures

• Implementing advanced weather prediction and early warning systems to alert at-risk populations.
• Designing & maintaining robust drainage systems & infrastructure to manage excess water flow.
• Planting trees and vegetation to improve water absorption and reduce surface runoff.
• Educating communities about the risks and safety measures during flash floods.
• Enforcing land use regulations to prevent construction in high-risk flood zones.

Measures Implemented in India to Address Flash Floods

• Prediction and Early Warning
  • The India Meteorological Department (IMD) uses Doppler radars.
  • They also employ flash flood forecasting and warning systems to predict flash floods.
• Preventive Measures
  • The National Disaster Management Authority (NDMA) provides recommendations to state governments, State Disaster Management Authorities, and District Disaster Management Authorities.
  • These recommendations include regulating habitation in low-lying areas along rivers, nullahs, and drains, which helps mitigate flood risks.
• Monitoring and Assessment
  • The Central Water Commission (CWC) and the National Remote Sensing Agency (NRSA) work with state governments and SDMAs for this purpose.
  • Satellite imagery monitors landslides and river blockages to identify potential flood hazards.

About Shyok River The Shyok River flows through the region of Ladakh in the northern part of India. It originates from the Rimo Glacier, a part of the Siachen Glacier complex, in the Karakoram Range. It flows eastwards through Ladakh and joins the Indus River near Skardu. The river’s course and the area around it hold geopolitical importance due to its proximity to the Line of Actual Control (LAC) between India and China. Due to its glacial origins and unpredictable flow patterns, the Shyok River is at risk from flash floods and glacial lake outburst floods (GLOFs). The river is also significant culturally, with local communities along its banks relying on it for various aspects of life, including agriculture, transportation, and cultural practices.

To know more about Floods in India, refer > Floods in India, Glacial Lake Outburst Flood