The Current Scenario

• The 2020 floods in Assam, caused by the overflowing Brahmaputra river, have put nearly 40 lakh lives at risk and caused massive property damage.
• The floods began in May 2020 due to heavy rainfall, leading to a rise in the water level of River Brahmaputra.
• The Impact-
  • 27 out of the 33 districts in Assam have been affected by the floods.
  • More than 3,000 villages have been submerged and around 1.3 lakh hectares of crops are estimated to have been destroyed.
  • According to the Assam State Disaster Management Authority (SDMA), the floods have claimed over 80 lives so far.
  • In the Kaziranga National Park, more than 75 animals have perished, while over 120 have been rescued.
  • This is not an isolated incident but a recurring issue in Assam.

Root Causes of Annual Flooding in Assam:

• The Brahmaputra river originates in the Tibetan plateau, where temperatures are rising by 0.42% every decade, leading to increased melting of glaciers and snow caps. This results in a higher water flow downstream.
• Assam, being located downstream of the river, is increasingly affected by floods.
• The Brahmaputra takes a sharp turn at Goalpara village, leading to frequent flood alerts in the area.
• Human encroachments and constructions in the flood plains of the Brahmaputra and its tributaries have obstructed the natural flow of water, exacerbating the flood situation.
• Highways and railway lines, constructed parallel to the Brahmaputra River to serve as flood barriers, have inadvertently prevented the outflow of water from inland areas into the river, causing localized flooding.

For more information on the major river systems in India, check out the linked article.

Why are Floods a Recurring Problem in Assam?

• Climatic Factors:
  • Assam, being a tropical monsoon rainforest climate region, experiences heavy rainfall and humidity.
  • The South-West monsoon typically brings heavy rainfall from June to September.
  • The onset of the monsoon season is often marked by damaging heavy showers and winds, locally known as ‘bordoisila’.
• Jhum Cultivation:
  • Jhum, or shifting cultivation, is a traditional farming practice in the hilly areas of Assam that involves slash-and-burn techniques.
  • The burning of vegetation removes the top layer of soil, making it more prone to erosion by rain.
  • Large amounts of soil and plant debris flow into the river basin, leading to silting.
• Silt Deposits in the Floodplain:
  • Several tributaries bring large quantities of water and silt from Arunachal Pradesh and the Barak valley.
  • This silt erodes the river banks and gets deposited in the river basin, making it progressively shallower.
• Climate Change:
  • Rising temperatures have resulted in increased rainfall and flash floods in recent years.
  • Heavy rain has reduced the water carrying capacity of the Brahmaputra and its tributaries.
• Encroachment of Wetlands:
  • The soil in wetlands acts as a natural sponge, absorbing excess water. Additionally, plants and roots in marshy lands slow down the progress of floods.
  • Rapid population growth has led to farming and construction activities in the wetlands.
• Dams on the Brahmaputra and its Tributaries:
  • Dams release large amounts of water during heavy rainfall to prevent hydrostatic pressure buildup.
• The Nature of the Brahmaputra River:
  • The Brahmaputra River frequently changes its course and has numerous tributaries.
• Deforestation:
• Inadequate Desilting Measures:
  • The implementation of desilting programs has been unsuccessful as they are temporary and costly.

Infrastructural Challenges in Assam Associated with Floods:

• The floods have submerged major and arterial roads in most districts.
  • National Highway 37 has been submerged in several places, particularly in the Kaziranga National Park.
• Train services have been disrupted as floodwaters have affected railway tracks in several locations.
• Most power stations, located near rivers for cooling purposes, have been damaged, resulting in power outages in many districts.
• There have been delays in providing relief and rehabilitating flood victims.

Technological Interventions:

• Accurate meteorological forecasting to predict the intensity and scale of floods for better planning of rescue measures.
• Construction of artificial embankments and restoration of existing ones.
• River dredging to reduce the sediment load in the Brahmaputra, an initiative currently being undertaken by the Assam government.
• Implementation of an integrated flood management program by the Government of India.
• Use of satellite imagery for monitoring and mapping changes in the river course.
• Flood inundation mapping and monitoring for improved research and policy-making.

The Silver Lining - Why Floods are Important for the North East Region:

• The soils in the North East region are primarily laterite soils, which are nutrient-deficient. The river water helps to enrich the soil with the nutrients needed by the region's thick vegetation and long-living trees.

The Way Forward:

• Implementation of flood plain zoning to prevent human settlement or agriculture in wetlands and high-risk flood zones.
• Re-evaluation of housing types in flood-prone areas. Houses built on stilts using bamboo are usually more resistant to damage.
• Social infrastructure such as schools, hospitals, and community centers should be located at a safe distance from flood-prone regions.
• Promotion of vegetation in wetlands and near riverbanks to act as a buffer against floods.

Related Resources:

For more in-depth analyses, check out our previous articles here .