Guwahati: Assam’s annual battle against floods has claimed over 2,200 lives and affected more than 9 crore people in the first quarter of the century, underlining the scale of one of India’s most persistent natural disasters.The 2026 flood season has once again highlighted the state’s vulnerability. At least 25 people have died and 100 reported missing in the last 24 hours, authorities said early on Wednesday, as Assam’s flood situation turned catastrophic with eight lakh people affected across 16 districts, raising the overall toll this monsoon season to 35. The Assam govt has placed the Army and the Indian Air Force on standby for rescue and evacuation operations in the worst-hit districts.Economic losses have also mounted sharply. Estimates show flood damage touching nearly Rs 50,000 crore between 2012 and 2024, based on the available official figures. Damage was estimated at Rs 10,339.66 crore in 2016, the highest loss recorded since 2012, followed by nearly Rs 10,000 crore in 2022 and about Rs 6,939 crore in 2024.A quarter-century analysis of official data from the Central Water Commission (CWC) for 2000-2011 and the Assam State Disaster Management Authority (ASDMA) for 2012-2026, up to July 22, reveals that floods have been a recurring feature of life in the Brahmaputra and Barak Valley for centuries, with huge human and economic impact.Every monsoon, heavy rainfall in Assam and the upper catchments in Arunachal Pradesh, Bhutan and Tibet swells the Brahmaputra and its more than 50 tributaries. Rivers frequently breach embankments and inundate vast stretches of the state’s floodplains. Scientists say high sediment loads, riverbank erosion, shrinking wetlands, encroachment on natural drainage channels and increasingly intense rainfall have together made flooding more frequent and destructive.The deadliest year in the dataset was 2004, when 497 people died and 126.30 lakh were affected. The next worst year was 2022, when floods claimed 181 lives and affected 57.50 lakh people.Assam’s recurring floods are driven by a combination of natural and human-induced factors. The Brahmaputra and Barak river systems, along with their tributaries, receive intense monsoon rainfall over Assam, Arunachal Pradesh, neighbouring hill states, Bhutan and Tibet, within a short span, leading to a rapid rise in river levels. The Brahmaputra is among the world’s most sediment-laden rivers, and its large, highly variable discharge, erodible banks and rising riverbeds due to silt deposition reduce carrying capacity, increasing the likelihood of overflow during the monsoon.An Assam State Disaster Management Authority report said deforestation in upper catchments and human interventions in both upstream hill states and downstream areas of Assam accelerated soil erosion, increasing silt deposition and surface run-off. As a result, riverbeds continue to rise, making floods more frequent.Rapid population growth, including migration from neighbouring countries, has led to unplanned settlements on floodplains and low-lying areas. Urban expansion, indiscriminate filling of wetlands and natural drainage channels, deforestation, changing land use patterns and temporary flood-control structures have further increased the state’s vulnerability to floods.According to the Flood Hazard Atlas, Assam (2016), prepared using the assessment of the Rashtriya Barh Ayog, about 31,500 sq km of Assam — 39% of the state’s geographical area — is flood-prone. This accounts for 9.4% of India’s total flood-prone area, despite Assam constituting only about 2.4% of the country’s land area.Nearly all major rivers in Assam are prone to flooding because they receive large volumes of water during the monsoon. The rivers carry massive quantities of silt and debris from the Himalayas, gradually raising their beds and reducing channel capacity. Consequently, even a few days of intense rainfall can cause rivers to overflow, inundating vast stretches of the Brahmaputra valley.
