Race against time to find workers missing in Nepal’s hydropower tunnels. Here’s what we know

Nepal’s Flooded Hydropower Tunnels: A Rescue Operation Against Mud, Darkness, and Time

Healfromzero.com – Flash floods that swept through Nepal’s remote mountain corridors last week have left at least 933 workers unaccounted for across multiple hydropower installations lining the Trishuli river. Thick deposits of mud and debris have sealed the entrances to reinforced underground tunnels, trapping crews whose fate remains unknown. Nepal’s national disaster agency confirmed the missing-worker count, though the precise number of individuals who were inside the tunnels at the moment the floodwaters struck has yet to be established.

The scale of the emergency is staggering. The Trishuli river carves through several districts in some of the country’s most isolated and rugged terrain, and the hydropower projects built along its course were designed to channel the enormous kinetic energy of Himalayan waterfalls into electricity. In recent years, Nepal, alongside its two superpower neighbors China and India, poured significant capital into such infrastructure, betting that the region’s torrential rivers could eventually power vast swaths of South Asia. That ambition now faces its most brutal test: rescuing the people who built the very tunnels now swallowing them.

The Scope of the Crisis

A tally compiled Saturday by the Independent Power Producers’ Association (IPPAN) placed roughly 900 workers missing across 11 separate hydro projects hit by the flooding. Each facility presents a distinct geometric and logistical puzzle for rescue teams attempting to identify the safest ingress route. Several of the affected plants contain internal passages extending several kilometers, meaning any worker caught inside could be separated from the nearest portal by an immense stretch of dark, reinforced concrete.

Survival odds inside those tunnels are uncertain. Built-in rooms and stored provisions could theoretically sustain trapped workers for weeks, yet the availability of breathable air remains the critical variable. Poor weather, ongoing mudflows, and the destruction of roads and bridges have compounded every aspect of the search, slowing both ground and aerial response.

Trishuli 3A: Boring Toward the Unknown

At the Trishuli 3A hydropower plant, where 42 workers are listed as missing, a large-scale drilling operation is underway to bore a shaft into the tunnel so that rescue teams can probe for survivors. The passage connecting the surface to the underground powerhouse—where dozens of personnel were on shift when the flood struck—measures more than four kilometers (2.5 miles) in length.

Arnold Dix, an Australian geologist advising the rescue effort at Trishuli 3A, explained that the extent of sediment and water filling the tunnel is still unknown.

“So, we might only have to dig 10 meters, or we might have to dig 100 meters.”

Dix highlighted additional hazards. If the plant’s emergency shutdown systems failed during the flood, the turbine chamber could have flooded entirely, drowning anyone inside. Moreover, the act of drilling through the tunnel ceiling risks releasing that stored water onto the rescue crews themselves.

On Monday, officials confirmed that rescuers had managed to cut an opening large enough to rappel into the tunnel using ropes and harnesses. They called out into the darkness and received no answer. In earlier attempts, teams pumped fresh air into the passage and lowered food supplies inside. The next phase, per officials, involves sending rescuers into the tunnel equipped with oxygen supplies, medical kits, communication gear, and cameras.

Breaking through the reinforced structure above the turbine room, however, demands specialized cutting equipment capable of penetrating multiple layers of steel and composite shielding.

“We need special equipment to get through the steel and everything that’s surrounding the turbine room. So, it’s layer upon layer of technical difficulties,”

Dix added.

Chilime: Chest-Deep Mud and a 130-Meter Standoff

Six workers are believed trapped inside the Chilime Hydropower Plant, according to Jenjen Lama, a mountain guide participating in the search-and-rescue operations. Lama shared a facility diagram showing a 250-meter (820-foot) tunnel descending before it joins a larger complex housing a service bay, control room, and the main transformer.

On Sunday, rescue teams discovered the tunnel passage

“completely blocked by deep, muddy sediment and sludge,”

with deposits reaching chest height. The teams advanced only 130 meters before conditions forced them to halt. Lama noted that the surrounding infrastructure damage also prevents helicopters from landing safely at the site.

Regarding the trapped workers’ prospects, Lama offered a measured assessment:

“There is the kitchen, there is some food … but I don’t know about the oxygen.”

International Reinforcement and the Broader Toll

Engineers and search-and-rescue units drawn from the Nepal Army and national police have been reinforced over the weekend by specialists dispatched by both India and China. Teams have deployed thermal-imaging cameras mounted on drones to scan for heat signatures, while simultaneously working to locate tunnel portals and excavate accumulated mud. In parallel, crews have been drilling vertical shafts through the heavily fortified tunnel roofs.

Dix estimated that as many as 27 hydropower plants sustained damage in the flooding, with approximately 12 rendered essentially inoperable. The economic and energy implications for a country still dependent on imported fuel for a large share of its electricity demand are considerable, and the reconstruction timeline will stretch across years.

Survivors Emerge

At least 279 hydropower workers have been rescued or have managed to force their way out of the mud- and silt-choked tunnels. Each survivor carries a harrowing account of hours or days spent in darkness, wading through debris, and waiting for help that arrived—when it arrived—only after an agonizing delay imposed by the very geography that made these projects possible.