Erosion and displacement of people

Himjyoti Brahma 

(himjbrahma@gmail.com)

The Brahmaputra is one of the world’s great rivers—powerful, sediment-laden, and restless. Originating in the Tibetan Plateau, it flows through China, India (primarily Assam and Arunachal Pradesh), and Bangladesh before joining the Ganges system and emptying into the Bay of Bengal. In Assam’s broad, flat valley, the river becomes highly braided and morphologically dynamic. This dynamism, intensified by natural and human factors, drives relentless bank erosion that has swallowed vast tracts of land and uprooted hundreds of thousands of people over decades. The crisis is most acute in Assam, where erosion represents a slow-onset disaster with profound social, economic, and cultural consequences.

The river’s restless character and causes of erosion

The Brahmaputra carries an enormous sediment load—among the highest of any major river—derived from the rapidly eroding Himalayas. In Assam, its gradient flattens dramatically, slowing the flow and promoting deposition and channel shifting. The river’s braided pattern features multiple shifting channels, sandbars (chars), and unstable banks composed largely of loose alluvial soil.

Several factors amplify erosion:

n The 1950 Assam earthquake raised the riverbed in places, increasing the frequency and intensity of floods while destabilising the banks.

n Intense monsoon rainfall (often exceeding 2,000–2,500 mm annually in parts of the basin) and high discharge create strong erosive forces.

n Climate variability is increasing the intensity of extreme rainfall events.

n Human interventions, including embankments that constrain flow, bridges, and land-use changes, can redirect currents and accelerate local bank failure.

Erosion occurs through the undercutting of banks, mass failure, and progressive channel migration. It is not uniform: rates vary by reach, with the southern bank often more vulnerable in parts of Assam, and certain districts experiencing chronic loss.

Scale of land loss

Official and scientific estimates consistently show severe cumulative impact. Since around 1950, the Brahmaputra and its tributaries have eroded roughly 427,000 hectares (about 4,270 square kilometres)—approximately 7.4% of Assam’s total area—at an average rate of nearly 8,000 hectares per year. The area occupied by the river itself has expanded markedly: surveys show it covering about 3,870 km² in the early 20th century, rising to around 6,080 km² by the mid-2000s. In places such as Dhubri, the river has widened by several kilometres in recent decades (for example, from roughly 8.4 km to over 13 km in one documented stretch).

Hundreds of villages Erosion has completely or partially erased hundreds of villages. completely or partially erased. Recent assessments indicate that erosion wiped out or heavily affected around 330 villages over a decade, with broader historical tallies pointing to well over 2,000 villages impacted and significant losses of fertile agricultural land, tea gardens, roads, and cultural sites. Majuli, the large river island and cultural heartland of Neo-Vaishnavism, has lost a substantial portion of its historical area and continues to shrink.

In Bangladesh, the Jamuna (the name of the Brahmaputra there) and related channels also cause substantial net land loss and recurrent displacement, though the focus of the most detailed long-term Assam-centric data remains on the Indian side of the basin.

Human displacement and its consequences

Erosion does not merely remove land; it dismantles livelihoods and communities. Families lose homesteads, farmland, and livestock. Many experience repeated displacement—sometimes several times within a generation—as they retreat inland, settle temporarily on embankments or remaining sars, or migrate farther afield.  Sar dwellers (river-island communities) and groups such as the Mising are particularly exposed; their traditional riverine adaptations offer limited protection against accelerating bank retreat.

Data on the exact number of displaced people are incomplete and sometimes contradictory. One recent account of the decade roughly spanning 2016–2026 reported more than 23,000 families affected across Assam districts, with Dhubri, Morigaon, South Salmara-Mankachar, and Barpeta among the hardest hit. Longer-term figures and parliamentary statements have cited tens of thousands of people rendered landless in shorter periods. Rehabilitation has lagged far behind need: many families receive little or no planned support, ending up on government or common lands, in informal settlements, or competing for scarce resources elsewhere. Such displacement can fuel local tensions over land and identity.

The socio-economic toll is heavy. Agriculture—the mainstay for most affected households—suffers permanent loss of productive land. Income drops, education is interrupted, health risks rise, and social networks fray. Cultural heritage is also at risk, as xatras (Vaishnavite monasteries) and traditional settlements on Majuli and elsewhere face an increasing threat. Tea estates in Upper Assam have reported loss of plantation land and risks to worker housing and infrastructure. Overall, erosion disproportionately harms poorer and more marginalized groups, reinforcing cycles of vulnerability.

Responses, limitations, and the path ahead

Assam has invested heavily in embankments (hundreds of kilometres) and local protection works such as porcupine screens, boulder spurs, and geotextiles. Many older embankments are ageing and prone to breaching. Larger initiatives include the Climate Resilient Brahmaputra Integrated Flood and Riverbank Erosion Risk Management Project and related programmes supported by the Asian Development Bank and national funding. These aim at reach-wise structural and non-structural measures, early warning, and better basin understanding.

Rehabilitation policies have been formulated (including a 2020 state policy), and recent efforts seek central funding for cluster housing and support for erosion-affected families. Implementation, however, has often been slow, underfunded, or constrained by eligibility rules and scarcity of suitable land. Accurate, up-to-date censuses of affected households remain a gap, complicating planning.

Sustainable progress requires a combination of approaches: improved river modelling and real-time monitoring; strategically placed, well-maintained protection works that work with (rather than rigidly against) the river’s dynamics; catchment management to moderate sediment and runoff where feasible; stronger land and resettlement frameworks that recognise repeated displacement; livelihood diversification; and climate-adaptive planning. Community participation and transparent data are essential so that responses match the lived reality of those who repeatedly lose their homes to the river.

The Brahmaputra will continue to reshape its valley. The challenge is to reduce the human cost of that reshaping—protecting lives, livelihoods, and cultural continuity while acknowledging the river’s fundamental power. Without sustained, science-informed, and people-centred action, erosion will continue to convert fertile land into water and settled communities into displaced ones.