Brahmaputra River

The Brahmaputra is one of Asia’s most significant transboundary river systems, flowing across southwestern China, northeastern India, and Bangladesh. Notable for its vast drainage basin, exceptional discharge, and complex fluvial dynamics, the river is central to the ecology, economy, and cultures of the eastern Himalayan and Bengal regions. It is known by different names along its course: Yarlung Tsangpo in Tibet, Siang or Dihang in Arunachal Pradesh, Brahmaputra or Luit in Assam, and Jamuna in Bangladesh. The lower distributary is called the Old Brahmaputra, and the combined Ganges–Brahmaputra–Meghna system forms one of the world’s largest deltas.

Origin and Early Course in Tibet

The Brahmaputra originates on the Angsi Glacier near Mount Kailash, north of Lake Manasarovar, in Burang County of the Tibet Autonomous Region. Earlier geographical accounts had placed the source on the Chemayungdung Glacier, southeast of Manasarovar. From its origin, the river, known locally as the Yarlung Tsangpo, flows eastward for several hundred kilometres between the main Himalayan range to the south and the Kailas Range to the north.
Numerous tributaries join the Tsangpo along this section. On the left bank, significant tributaries include the Raka Zangbo and the Lhasa River, which meets the Tsangpo near Qüxü. On the right bank, the Nyang Qu merges near Xigazê. After leaving the high plateau, the river carves a dramatic course through the rising Himalayas, cutting a succession of narrow gorges between Gyala Peri and Namcha Barwa. The deep, winding Yarlung Tsangpo Grand Canyon, one of the deepest in the world, marks the river’s abrupt southward turn toward India. The river’s identity with the Brahmaputra was confirmed only in the late nineteenth century following extensive exploration.

Entry into India: Arunachal Pradesh

Crossing the China–India boundary, the river enters Arunachal Pradesh as the Siang. It descends rapidly from the Tibetan plateau and emerges onto lower terrain as the Dihang. Flowing southwards, it soon meets the Dibang and Lohit Rivers at the eastern edge of the Assam Valley. After this confluence, the river assumes the name Brahmaputra. Indigenous Bodo communities have referred to it by names such as Doima (“mother of water”) and Burlung–Buthur.
The Brahmaputra is unusually broad in Arunachal Pradesh and Assam, where its width may extend several kilometres. This dramatic change in course and profile reflects the river’s antecedent nature—it predates the uplift of the Himalayas and maintained its course by cutting downwards as the mountains rose.

The Brahmaputra in Assam

As the Brahmaputra enters Assam, it spreads into one of the world’s most extensive braided river systems, with a shifting pattern of sandbars and islands. Even in the dry season, the river remains large, and during monsoon months its banks may lie many kilometres apart.
Major northern tributaries descending from the Himalayas include the Subansiri, Kameng, Dhansiri, Manas, Sankosh, and others. From the south, important tributaries include the Burhi Dihing, Disang, Dikhu, and Kopili. Between Lakhimpur and Dibrugarh, the river divides into two distinct channels—Kherkutia in the north and the main Brahmaputra channel in the south—which reunite downstream to form Majuli, the world’s largest river island.
Near Guwahati, the channel narrows sharply as it cuts through the Shillong Plateau, creating a strategic choke point historically significant in the Battle of Saraighat (1671) between the Ahom Kingdom and the Mughal Empire. Guwahati later became the site of the first combined road–rail bridge over the Brahmaputra, completed in 1962. Ecologically, the surrounding floodplains form the Brahmaputra Valley semi-evergreen forests.

Course Through Bangladesh

After crossing into Bangladesh below the Garo Hills, the river is joined by the Teesta, one of its largest tributaries. South of this confluence, the river diverges into two distributaries:

• The Jamuna, carrying the greater portion of the flow, continues south to meet the lower Ganga (Padma River).
• The Old Brahmaputra, once the dominant channel, now much smaller, curves southeast to join the Meghna River near Bhairab Bazar.

This complex distributary network forms part of the Ganges–Brahmaputra–Meghna delta. After the Padma and Meghna merge near Chandpur, the combined waters flow into the Bay of Bengal. Additional tributaries and distributaries, such as the Dhaleswari, Baral, Atrai, Hurasagar, and Buriganga, support the intricate hydrology of the region, with the Buriganga passing the capital, Dhaka.

Hydrology and Fluvial Characteristics

The Brahmaputra is among the world’s major rivers by discharge and length. Its flow exhibits dramatic seasonal variation due to Himalayan snowmelt and monsoon rains. Spring and summer commonly bring severe flooding, often affecting large populations in Assam and Bangladesh.
Key hydrological features include:

• Braided channels, reflecting high sediment loads and variable discharge.
• Tidal bore occurrence in downstream reaches, a rare phenomenon globally.
• High susceptibility to avulsion, where rapid channel shifts occur across the floodplain.
• Navigability along most of its course, making it vital for transportation.

The basin includes diverse physiographic regions: the Tibetan plateau, the eastern Himalayas, the Patkai hills, the Meghalaya plateau, the Assam plains, and lowland Bangladesh. Kangchenjunga, at 8,586 metres, forms the highest point within the basin.

Cultural and Historical Significance

The lower reaches of the Brahmaputra hold sacred value in Hinduism. The river is one of the few in the subcontinent to bear a masculine name, meaning “son of Brahma” in Sanskrit. Its various regional names reflect the cultural diversity along its course.
The Brahmaputra has shaped settlement, agriculture, and trade for millennia. Its floodplains sustain extensive rice cultivation and fisheries, while its tributaries help support rich biodiversity. The river’s shifting channels and periodic inundations also present longstanding challenges for infrastructure, flood control, and regional planning.