KATHMANDU: Nepal will begin design work this fiscal year to drain four dangerous high-altitude glacial lakes, officials said, as the Himalayan nation scrambles to reduce flood risks after August's catastrophic glacier collapse killed more than 1,400 people and left over 5,000 missing along the Nepal-Tibet border.
The lakes — Thulagi, Lower Barun, Lumding Tsho and Hongu II — sit between 4,050 and 5,483 metres (13,280 to 18,000 feet) in central and eastern Nepal. A 2020 assessment by the United Nations Development Programme and the International Centre for Integrated Mountain Development (ICIMOD) ranked them among the country's most dangerous glacial lakes.
The August Catastrophe Behind the Decision
August's disaster began with a glacier collapse that unleashed a cascade of landslides and a flash flood which tore through valleys on the Nepal-China border, sweeping away roads, bridges and buildings. Rescue teams are still searching for more than 5,000 people reported missing.
"Our aim is to lower the risk of the lakes breaching their natural dams and reduce the risk of downstream floods," said Subash Tuladhar, an expert with Nepal's Centre for Hydrology and Water Resources Research, the government body overseeing the project.
The Four Lakes in the Crosshairs
Design work and detailed studies targeting the four lakes will begin in the fiscal year that runs until mid-July 2027, authorities said. All four rank among Nepal's most potentially dangerous bodies of water, per the 2020 UNDP-ICIMOD report — the kind of moraine-dammed lakes that can burst without warning when glaciers above them destabilise.
How the $50 Million Drainage Will Work
Water will be drained through canals into nearby rivers in a regulated way, Tuladhar said, while full drainage "through gated structures" will start only after detailed studies. The centre's executive director, Sanjeeb Baral, said that phase could take up to six years to complete.
The roughly $50 million project is to be funded by the Green Climate Fund, the UNDP and the Nepalese government. Beyond the drainage itself, it will add sensors, flood forecasting and early-warning systems, plus work to build downstream resilience and prepare communities for the risks.
Officials acknowledge the human cost of the work itself: crews face health risks from lengthy periods at extreme altitude, on top of the danger of sudden flooding while they work.
A Race Against the Next Disaster
Nepal has recorded about 26 glacial lake outburst floods in four decades, and the country has done this before — ten years ago it lowered Imja lake near Mount Everest, the world's tallest peak. But the scale of the August disaster has forced a far more ambitious response.
Prime Minister Balendra Shah told the United Nations last month that retreating glaciers and unstable slopes show Nepal is paying a heavy climate cost despite its low emissions. With thousands of glacial lakes sitting above Himalayan villages, the four-lake drainage plan is a test of whether engineering can buy downstream communities the one thing they have never had: warning.
Sources: