Budhi Gandaki

The Budhi Gandaki (Nepali: बुढीगण्डकी, also written Buri Gandaki or Burhi Gandaki) is a major river of central Nepal and one of the principal tributaries of the Gandaki (Narayani) river system. It rises among the glaciers and snowfields of the high Himalaya on the northern flanks of the Manaslu Himal, close to the Tibetan border in northern Gorkha District. From its headwaters near the high Larkya region it flows broadly southward for roughly 130 kilometres before joining the Trishuli River at Benighat, on the boundary between Gorkha and Dhading Districts.

For much of its length the river runs through one of the deepest and most dramatic gorges in Nepal, hemmed in by the snow peaks of Manaslu (8,163 m, the world's eighth-highest mountain) to the west and the Ganesh Himal to the east. The upper valley begins among Tibetan-influenced Buddhist settlements such as Samdo and Sama Gaun, which lie at altitudes of around 3,500–3,900 metres, and the river then descends steeply past villages including Namrung, Deng, Philim and Jagat. In its middle and lower course it passes the riverside towns of Machha Khola, Soti Khola and Arughat before reaching the confluence at Benighat, near 478 metres above sea level.

This descent of more than 3,000 metres in a relatively short distance carries the river through a striking sequence of climatic and ecological zones — from alpine and sub-alpine terrain in the north, through temperate forest, down to the warm subtropical hills of the lower valley. The narrow, fast-flowing gorge has historically made the valley difficult to access, and the trail that threads along the river, crossing it repeatedly on long suspension bridges, forms the lower section of the popular Manaslu Circuit trek.

The Budhi Gandaki is a snow- and glacier-fed Himalayan river, so its flow is strongly seasonal: discharge swells during the summer monsoon (roughly June to September) when rainfall combines with snow and ice melt, and falls to a much lower base flow in the dry winter and spring months. Its drainage basin covers approximately 5,000 square kilometres. The greater part of the catchment lies within Nepal — about 2,700 square kilometres in Gorkha District, around 900 square kilometres in Dhading and a small portion (roughly 35 square kilometres) in Nuwakot — while some 1,365 square kilometres of the upper basin lie across the border in China (Tibet).

The river drains the southern slopes of the Manaslu and Ganesh ranges, gathering numerous small mountain streams and side torrents as it cuts through the gorge. After collecting these waters it discharges into the Trishuli at Benighat; the Trishuli in turn is one of the main headwater rivers of the Gandaki (Narayani), which flows on to the Terai and across the border into India, where it is known as the Gandak before joining the Ganges. The Budhi Gandaki is conventionally counted among the principal tributaries of the wider Gandaki system alongside rivers such as the Kali Gandaki, Marsyangdi, Madi, Seti and Daraudi.

The Budhi Gandaki is best known nationally as the site of one of Nepal's largest planned infrastructure projects, the Budhi Gandaki (Budhigandaki) Hydroelectric Project. This is a proposed storage (reservoir) scheme with a planned installed capacity of 1,200 megawatts, which would make it among the biggest power projects in the country. It is to be built on the river upstream of the Trishuli confluence, about 55 kilometres west of Kathmandu, straddling Ghyalchok in Gorkha District and Salang in Dhading District.

The centrepiece is a concrete dam planned at about 263 metres high, which would rank among the tallest dams in the world, impounding a reservoir roughly 45 kilometres long with a surface area near 49.8 square kilometres. The scheme is designed to generate on the order of 3,383 gigawatt-hours of electricity a year and, as a storage project, would help firm up Nepal's seasonally variable hydropower supply. Preliminary studies date back decades, and the project has long been promoted as a flagship of Nepal's energy ambitions, with the Nepal Electricity Authority (NEA) taking a lead role.

Funding has been raised in large part through a dedicated infrastructure tax levied on petroleum products, and the government has spent heavily acquiring land in the reservoir area. The project's history has been marked by political reversals over Chinese involvement: a memorandum of understanding was signed with China Gezhouba Group Corporation in 2017, scrapped later that year, re-awarded in 2018 and then revoked again in 2022, after which the government moved toward developing it domestically through the NEA. As of the mid-2020s the dam remained unbuilt, with construction repeatedly delayed.

The Budhi Gandaki valley is culturally layered along its length. The high upper valley around Samdo, Sama Gaun and Lho is home to communities of Tibetan Buddhist heritage, dotted with monasteries (gompas), mani walls, chortens and prayer flags, and closely linked across the mountains to Tibet. As the river descends, the middle and lower valley shifts toward a mixed Hindu and hill-ethnic population, and towns such as Arughat reflect a blend of Hindu and Himalayan traditions. This makes the valley a corridor between two of Nepal's great religious worlds.

Like other rivers of the Gandaki system, the Budhi Gandaki carries broader Hindu significance through its parent river. The Gandaki basin is famed as the source of shaligram (saligram) — black ammonite fossil stones revered by Hindus as aniconic forms of the god Vishnu — which are gathered from the bed of the Gandaki and its tributaries. The river valleys of the region are thus woven into pilgrimage and ritual life, and the Manaslu region through which the Budhi Gandaki flows is itself a sacred landscape, with Mount Manaslu's name derived from the Sanskrit manasa, meaning 'intellect' or 'soul'.

As a steep Himalayan river draining a high, geologically young and seismically active mountain region, the Budhi Gandaki valley is exposed to natural hazards including landslides, flash floods and the risk of glacial-lake outburst floods from the snow and ice fields at its head. The deeply incised gorge concentrates these flows, and the wider Gandaki basin lies within the earthquake-prone central Himalaya — factors that bear directly on the safety and engineering of any large dam on the river.

The dam project has been a focus of environmental and social controversy. Its 45-kilometre reservoir would inundate a long stretch of inhabited valley, and estimates indicate that on the order of 45,000 people would be displaced, with large areas of farmland, forest and settlement submerged. The catchment supports extensive forest and a notable diversity of wildlife, so the loss of riverine and forest habitat is a significant concern. Beyond the local impacts, energy-sector analysts have repeatedly questioned the scheme's financial viability as the costs of solar and wind power fall, leaving the long-promised mega-dam, in the words of one assessment, something of a 'mirage' even after years of land acquisition and tax collection.