Two workers at a construction site of Melamchi Water Supply Project in Sindhupalchok went missing when they were swept away by a high-velocity water released through one of the tunnels as part of a routine test on Tuesday.

Police said search was underway for Satish Goit, one of the project engineers, and Radha Krishna Thapa Magar, a driver, who went missing in the accident.

Shekhar Khanal, site engineer, and Pemba Lama, a project helper, were rescued and taken to Kathmandu for treatment.

“The two men have sustained deep injuries in their heads and legs,” said Superintendent of Police Prajjwal Maharjan.

The water released to the main tunnel in the intake area at Helambu Rural Municipality-1 had swept away the four men who were at the site.

The incident occurred at around noon at Gate No 17, some 800 metres inside the tunnel, a project employee said on condition of anonymity since he was not authorised to speak to the media.

According to some of the technicians, who have been working on the site, a high pressure water was released, which led to excessive water flow through the gate pushing the water back to the mouth of the tunnel.

“We used to measure the water pressure every hour. There was no reason for this to happen but we don’t know the technical aspect,” said Krishna Tamang, a project worker.

The Post tried to contact Triresh Prasad Khatri, the project chief, for a comment, but his mobile phone was switched off throughout the day.

The high-velocity water also destroyed the majority of infrastructure, including the main audit and headworks area.

“The infrastructure inside the tunnel has been damaged. We haven’t been able to reach the incident site to determine the cause of the incident,” said Shiva Kumar Sharma, an engineer at the project.

He said a technical team had been formed at the ministerial level to probe the incident.

Another project official said it would take around three weeks to repair the damaged tunnel gate.

Works were underway at the main tunnel and Gate No 17 to channelise water to Sundarijal of Kathmandu from Melamchi River in Helambu.

Some witnesses reported a torrent of water gushing out from the tunnel and sweeping away a project vehicle.

The incident has raised concern among the locals. They questioned the quality of the much-awaited national pride project.

“Our settlement can be swept away at any time due to the poorly-built infrastructure of the project. We don’t know how technically sound the infrastructure is,” said Mingmar Hyalmo of Helambu. “The government should inspect the incident site immediately and find out where the problem lies.”