It was estimated that 42 people were trapped when the tunnels of the Trishuli-3A hydropower project were flooded. The entrance of the tunnel was covered with about 15 meters of clay, stones, gravel and sand. There was no way for the rescue team to enter the tunnel.
Engineer Shriram Neupane and Sagar Dhakal started preparing for the rescue from the night of August 11. After inspecting the site on the 12th, they surmised that some people might be alive in the upper part of the power house. The most likely route to reach it was a 160m long cable duct tunnel.
18,000 to 20,000 cubic meters of lead and other materials had to be removed to open the tunnel. After four days of 24-hour work, the top of the entrance was reached. After that, a trained rescue team of Nepali Army and Armed Police moved forward. Rescuers entered the tunnel using water jets to remove the lead. After reaching about 130 meters out of 160 meters, a noise came from inside the tunnel.
The answer came from there, "Okay."
That moment changed the direction of the rescue mission. But even then there was a net obstacle in the way. Once the savior himself was at risk. Work stopped for a few hours. Making their way again, two men were eventually pulled out alive. Edited part of the conversation of Janardan Baral of Online Khabar with MPs and Engineers Sriram Neupane and Sagar Dhakal who were directly involved in the rescue operation:
When did you join the rescue?
Neupane: On 10th of August, the flood in Trishuli river caused huge damage to the hydropower project and the settlements along the river. I received information through Sagar Dhakal on the night of the 11th that 42 people were trapped inside the tunnel in Trishuli-3A.
At around 11 o'clock that night, a Zoom meeting was held with the Nepal Electricity Authority team. Possible rescue measures were discussed. I said that without understanding the situation on the ground, it is impossible to say the solution. Then it was decided to go to the site the next day.
On the 12th, we reached the Nepali army barracks at Bidur. There was a discussion with security agencies and officials of Nepal Electricity Authority. After that, we reached the site by helicopter and discussed the maps, drawings and the technicians there.
After looking at the site, some options were seen based on the structure and condition of the tunnel. People who reached the top of the power house were likely to be safe. So our main focus was on finding a way to reach them.
There were four possible paths to get there. The road to the headworks was a long one. Passing through the tailrace led to the lower part of the power house, where everything was filled with ledos. The access tunnel was also buried as it sloped towards the direction of the flood.
The cable duct tunnel was 160 meters long and climbed upwards. Its upper compartment reached the top of the power house. So it was decided to open that way.
But the entrance to the tunnel itself had turned into a bugger. It was covered with stones, gravel, sand and clay up to about 15 meters. First, the actual direction of the tunnel had to be found.
For that, we worked to find out the alignment of the tunnel by drilling upstream. In that process, help came from various technicians to gather the necessary machines and equipment. On the 13th the machine was brought to the site and drilled about 24 meters upwards. This confirmed the direction of the tunnel.
On the 13th we identified the tunnel entrance and direction. The actual excavation began on the morning of the 14th.
What was the biggest challenge you faced during the rescue?
Neupane: The biggest challenge was removing the debris piled up on the tunnel. What kind of machine is needed, what kind of pipe is needed, what kind of pump is needed, how much manpower is needed, what material is to be brought from where, everything had to be managed immediately.
Worked 24 hours a day for four days. After removing about 18,000 to 20,000 cubic meters of material, the upper part of the tunnel entrance was reached.
After that, the trained rescue personnel of the Nepali Army and Armed Police started entering the tunnel by making a three-foot path. A water jet was used to remove the lead. The rescue team continued to advance.
Dhakal: After overcoming one obstacle in this rescue, another obstacle would come. Every time a new solution had to be devised.
For example, using a water fountain to enter the tunnel was not planned from the beginning. While working, that's where the solution came from.
At 3A, the tunnel ascended upward. But the situation is different in Chilime. There is a tunnel down there. So what works in one place may not work in another place. The solution should be changed depending on the condition of the field.
When we got within about five or seven meters, a very scary thing happened. A narrow path was formed between the debris at the top. From there the rescuers were advancing.
Suddenly a heap of material fell from above and blocked the road. On one side, the people inside the tunnel, on the other, the rescuers got stuck. The person who went to rescue had to be rescued first.
It was a very tense moment for everyone. It was not possible to proceed without risking the saviour. They had to be taken out and given confidence. The road had to be cleared again. It took another five-seven hours.
How was it confirmed that people are alive inside the tunnel?
Neupane : After reaching about 130 meters out of 160 meters, the rescue team saw a small opening. A voice came from there.
The rescue team said, "We are in rescue, we are coming, don't worry." From there again came the voice of 'yes'.
More than one man's voice was heard. At first it was suspected that there might be an echo. But the rescue team confirmed that it was more than one person's voice. Then it was confirmed that the man was still alive.
Dhakal: Hearing that voice was a very emotional moment. We were working continuously for three to four days. One day he could not sleep more than a few minutes in almost 24 hours.
That day I went to bed around 1 am. When I woke up around 3, 3:30 or 4 am, I heard a noise. At first it was hard to believe. Had to confirm if it was a two-way communication.
Neupane: It was about 30 meters from the place where the sound was heard. The path was blocked by a net in front. Had to come out and get the necessary tools to cut it. It also took two to three hours.
Finally two people were rescued alive.
There was also an allegation that the rescue was delayed. Did you spend more time in preparation and discussion?
Dhakal: Sooner or later we have to understand what the situation was like. This was no ordinary flood. Routes, access and damage conditions were extremely complex.
On the day of the flood, a team was formed at the Prime Minister's Office and sent to the drone field. On the 11th, a plan was made from where to build the base camp to the priority of rescue by sitting in the disaster management structure under the Ministry of Home Affairs.
It was estimated that 40-42 people were trapped in Trishuli-3A and it was seen as one of the most difficult rescues due to the condition of the structure. Therefore, it was not possible to enter the tunnel directly without preparation.
Where did you see the main weakness in the preparation of the government?
Dhakal: The main gap is in our assessment and preparedness. Resources and manpower must be divided when rescues are to be carried out in many places at the same time. 'Actor mapping' is common in international practice. In which place, who has what capacity, who has what equipment, which company has what kind of manpower, which specialist can do what work, the details are prepared in advance.
There is no such detailed mapping in Nepal. Even in the field of tunnels, separate details of who is the designer, who is the expert in implementation, who can operate the machine, and who can repair it are necessary.
There may be many people who come to say 'I am an expert' after a disaster. But it should be known in advance which expert can do what job.
Neupane: The government and related organizations should prepare a list of experts with their contact numbers. It is important to have someone on site who knows what equipment is needed in a rescue, where to find it, what manpower is needed and how it can be provided within an hour.
Bringing the entire team of a large organization to the site is not enough. Everyone needs an experienced person who can sit on site and direct them, identify the necessary materials and manpower and mobilize them immediately.
There is also a complaint that foreign and local experts were not called on time.
In times of disaster, we need people who can act immediately. Advice and design are also necessary, but then manpower who can go into the field and implement is even more important.
It is not that we do not listen to foreign experts. But instead of 5-10 experts coming in helicopters and crowding the field, they can sit in a safe place and send a clear solution by looking at available videos, maps and designs.
We did the same in Trishuli-3A. Australian tunnel expert Arnold Dix was also contacted and consulted. But it is not always possible for a foreign expert to arrive at the scene immediately. So our own capacity and preparation must be strong.
Unnecessary crowding at the rescue site may hamper the work. One day many helicopters came. Some people came with cameras, took pictures and returned.
This is not a tourist place. Experts should not come to the rescue site and increase the crowd, but should come with the solution that they can provide.
We also told foreign experts—not everyone has to come to the site. We will send the video, design and other details. You should sit down in a safe place and discuss and come up with possible solutions.
The Prime Minister said in the Parliament that the expertise to rescue this kind of tunnel buried by lead is not only in Nepal, but not in the world. Is that the reality?
Neupane: It should be corrected a little and understood. He may have said in the sense that the technology to immediately open the tunnel and extract people is not available all over the world. But this does not mean that there is no technology in the world to rescue such a tunnel.
How long a rescue takes depends on the technology used, equipment, geography and conditions. Some techniques can do it faster, some slower.
So Trishuli-3A should be made a case study. Let's study how long it will take, what technology and equipment are needed, and what kind of manpower is required by having foreign experts work on the same case. From that, it is clear what kind of equipment and capabilities Nepal should develop in the future.
Dhakal : A method we used in 3A may not work in Chilime. At 3A, the tunnel ascended upward. In Chilime the situation is reversed.
There we have to look at the site again and come up with a new solution. It is only after reaching the field that the topography, water flow, tunnel slope and debris conditions are visible. Therefore, the same technology or the same machine is not applicable everywhere.
Neupane: This incident has shown us that we need to reconsider some things in tunnel construction.
A door can be placed at the mouth of the tunnel which can be closed in case of emergency. An emergency room should be built in a technically safe part of the power house, where food, water, light and necessary facilities can be kept for a few days.
While determining the location and height of tunnels and power houses, the likely direction of flooding should also be taken into account. I have thought of preparing a detailed study and research paper covering these topics. Necessary standards and procedures should also be developed for such tunnels in future.
Dhakal: We conduct regular emergency training while working abroad. It is practiced by creating an emergency situation at intervals of few months. There is a provision to pass the exam every year.
We have a 'runaway bag'. If you have to leave immediately in an emergency, you can leave with the same bag. It contains necessary lighting, food and other basic materials.
Many hydropower plants in Nepal do not have such preparedness and regular emergency drills. This is an issue that needs immediate improvement.
It was initially estimated that 42 people were trapped in Trishuli-3A. Two people were found alive and one dead body. What about the rest?
Neupane: Out of the total 42 people, we saw the possibility that those who reached the top of the power house would survive.
We have also seen a video taken by a local during the flood. Analyzing it, 31 people are seen gradually coming out of the power house. The scene of some of them being chased by trident is also seen in the video.
Then we rescued two people alive who could be in the safe part of the tunnel. A dead body was also found. In the case of the remaining eight people, it seems that they may have been swept away by the river, buried in a tunnel or somewhere outside, or run away.
The rescue team said that the search for the potentially safe part of Trishuli-3A has now been stopped.
Now what is being done to rescue the people who are said to be trapped in Chilime?
Neupane: The situation in Chilime is different from 3A. There is access to about 250 meters of the tunnel, but the upper part is still closed. It is also not possible to carry more people by helicopter.
The first task is to create an access road where people can walk. For that, the blasting and drilling materials used in 3A have to be moved there. Another big challenge is getting the lead out of the tunnel. There is a possibility that a rope system or a winching machine can be used for that.
If a road can be made where people can walk, it can be taken out by mobilizing a large number of people.
Dhakal: Now we have started the design and manufacturing of Ledo pulling machine. We don't just go there to advise, we design, build and implement ourselves.
This is the reason why we need manpower who can execute the work rather than writing a report during the disaster.
Neupane: The biggest lesson I learned from this incident is preparedness. A clear plan on how to act in the event of such a disaster in the future is essential.
Not just by blaming our geography. This geography is our source. Water and river can become the basis of prosperity for us. But if it is not managed, the same resource can become the cause of destruction.
Therefore, disasters should not only be seen as damage, but also as an opportunity to make settlements, infrastructure and hydropower projects safer during reconstruction.
Dhakal: This is the biggest lesson today. Before disaster strikes, we need to know—which engineers are where, who has what equipment, who has what expertise, and who to deploy in what situations.
We need a structure with proven capabilities and responsibilities, not an 'I'm an expert' system that comes in during a crisis.
We should start this work within a month or two. The situation of trying to find out who to call after a disaster should not happen again.
