Rapid construction in Himalayan high-risk zones puts 300,000 people in harm's way, study finds
A peer-reviewed study has found that built-up land in high-risk zones across parts of Nepal, south-eastern Tibet and India's Uttarakhand expanded by about 45 percent between 2016 and 2023, leaving at least 300,000 people exposed to potential glacial lake floods and other disasters.
BBC World
At least 300,000 people in parts of the Himalayan region could now be living in the path of potential disasters, according to a peer-reviewed study published in the journal Scientific Reports.
Researchers found that the amount of built-up land in high-risk zones across northern Nepal, parts of south-eastern Tibet and a corner of India's Uttarakhand grew by roughly 45 percent between 2016 and 2023. In areas particularly threatened by flooding from glacial lakes, development rose even faster, increasing by almost 78 percent over the same period. The team said the true number of people under threat could be much higher, because the study covered only a specific territory and not neighbouring areas facing similar risks.
Nine researchers from the UK, Nepal and India examined areas up to 50 kilometres downstream from Himalayan rivers, as well as around 1,360 glacial lakes. They documented significant expansion of tourism facilities, infrastructure and real estate, including in Pokhara, a major tourism hub that has grown substantially over the past 30 years. Mayor Dhana Raj Acharya said managing the risk posed by the Seti Gandaki River, which flows through the city from the Annapurna range, is a huge challenge, noting that many old buildings stand just five metres from river banks despite new rules requiring greater distance. "Where we move them, and how we do that, is the real challenge," he said.
The study was completed before August's devastating mass floods, which left more than 1,400 people dead and thousands missing in Nepal. Smaller incidents have followed, including flooding along the Budhi Gandaki river on 11 October that damaged 200 houses, swept away five bridges and left five people missing. During the catastrophic flooding on 26 August, locals in Rasuwa district reported that river levels rose by as much as 70 metres at some points, well beyond the 50 vertical metres the researchers used to define buildings at risk, suggesting the true exposure could be even greater.
Tourism operators in the Annapurna trekking region, where settlements along river banks have increased sharply, described mounting anxiety. Phurpa Chhiring Lama, who runs a homestay, said only five of his 20 rooms were occupied during the peak trekking season, having never seen such disasters in more than 40 years in the business. Krishna Gauchan, whose hotel sits near the glacier-fed Modi river, said residents live in constant fear of a glacial lake outburst. Khagendra Poudel, a geographer at a local campus of Tribhuvan University, suggested tourism investors promote destinations without factoring in the risks, and the president of the Hotel Association Pokhara, Laxman Subedi, acknowledged the sector had expanded without proper planning. "By the time disasters hit, it is too late," he said.
Development pressure is not limited to tourism. The regions around the Bhotekoshi and Trishuli rivers have seen a significant rise in hydropower plant construction. Lead author C Scott Watson, a glaciologist at the University of Leeds, warned that development decisions being made today will shape disaster risk for decades to come as river valleys become increasingly populated.
The risks are largely driven by warming in the Himalayan region, which scientists say is occurring at twice the global rate. Accelerated melting of glaciers, icefields, snowpacks and permafrost can destabilise mountain slopes that are also frequently shaken by earthquakes, while expanding glacial lakes can burst and cause deadly floods. Nepal alone has documented around 30 such events since 1940. Rising temperatures also mean rain now reaches high altitudes where snow once fell, contributing to slope failures and rock and ice falls. Nepal's Prime Minister Balendra Shah told the recent UN General Assembly that his country was paying a "colossal price" for a crisis it did not create.
Enforcement of building regulations remains weak, according to campaigners and experts. Prof Surya Raj Acharya, an urban planning expert and registrar at the University of Nepal, said roads, hydropower projects, hotels and market towns have expanded on accessible low-lying land along rivers, with safeguards often ignored. Alton Byers, a mountain geographer at the University of Colorado who was not involved in the study, said it should serve as a springboard for better early-warning systems and precautionary measures. Nepal's national disaster agency said settlements within 15 metres of the riverbank along the devastated Rasuwa-Bhotekoshi corridor will soon be banned, with similar rules planned for other river corridors, though chief executive Dharam Raj Uprety acknowledged the difficulty of relocating people attached to their land.
Across the border in India's Uttarakhand state, activist Anoop Nautiyal claimed maximum tourism limits and environmental regulations have been bypassed in the name of economic growth, with rampant construction visible despite zoning rules on paper. The state government approved new floodplain zoning rules on 12 October to regulate land use and protect life, property and infrastructure. Basanta Raj Adhikari, director of the Centre for Disaster Studies at Tribhuvan University, cautioned that such threats cannot be fully mitigated, and suggested risk-based insurance grading could encourage safer construction. For now, however, the pace of construction across the region shows no signs of slowing.