Nepal will study draining Thulagi, Lower Barun, Lumding Tsho and Hongu II

Nepal will begin design work this fiscal year on draining four glacial lakes, after August floods and landslides killed more than 1,400 people and left more than 5,000 missing in the border region near China. The lakes are Thulagi, Lower Barun, Lumding Tsho and Hongu II, in the centre and east of the country. Officials rate them among Nepal's most dangerous.

Subash Tuladhar, of the Centre for Hydrology and Water Resources Research, said the aim is to lower the risk that the lakes breach their natural dams and flood the valleys below. Canals would send water into nearby rivers in a controlled way. Sanjeeb Baral, the centre's executive director, said the draining itself, through gated structures, starts only after a detailed study and could take up to six years. The fiscal year for the design work runs to mid-July 2027. The project is costed at 50 million dollars. The Green Climate Fund, the UN Development Programme and the Nepali government are the funders Tuladhar named.

The August disaster began with a glacier collapse. Search crews are still looking for the missing. Prime Minister Balendra Shah has tied the death toll to climate pressure on the high mountains. The four lakes in the new plan are a separate risk from the glacier that failed in August. A glacial lake outburst flood happens when a moraine or ice dam gives way and the water behind it goes downstream in a single pulse. Lowering the water before that break is the point of a drain. It does not rebuild the villages already buried.

The work is dangerous for the crews as well as for the people below. Tuladhar said workers face health risks from long periods at altitude, and the risk of a sudden flood while they are on the dam. That is why the first year is studies and design, not excavators on the moraine. Sensors, a flood forecast and warning system, and downstream preparation sit in the same project. A gate that lowers a lake by a few metres is useless if the valley below has no siren and no practised route uphill.

Nepal has done this kind of work before. Tsho Rolpa, above Rolwaling, was lowered in an earlier project after it was judged close to failure. The new list is larger, four lakes rather than one, and the budget is explicit: 50 million dollars, shared by a climate fund, a UN agency and the state. Baral's six-year window is the part that should be read against the August toll. Design through mid-2027 means the physical drain may not be finished until the early 2030s. The lakes do not wait on a fiscal calendar. A hot season or a heavy monsoon can raise them before a gate exists.

The missing-person figure is the other clock. More than 5,000 people were still unaccounted for when Reuters filed the drain story on 2 October. Identification in a flood of this scale depends on DNA and on families who can reach a collection point. Dawn, the same week, reported a father in Nuwakot holding a photograph of his son and waiting on a DNA test. That queue is not part of the lake project. It is the reason the project is being announced now rather than after another outburst.

What the announcement does not yet include is a lake-by-lake volume, a target drop in water level, or a start date for construction. Those numbers come out of the study Baral described. Until they exist, the commitment is a shortlist of four names, a 50 million dollar envelope, and a method: gated drains into existing rivers, plus sensors and warnings. The test of the plan will be whether Thulagi or Lower Barun has a gate in the ground before the next monsoon that overfills a moraine. Six years is the outside estimate. The August collapse has already shown what an ungated failure costs.