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2023. Sep VOL. 666
2023. Sep VOL. 666
How are you, Mr. Yu? My name is Lee Du-hui, and I am working as deputy head of the department responsible for the management and operation of Soyanggang Dam. I was assigned to the current post last July and since then I have been busy like a hen with one chick, trying to deal with floods and algal bloom that struck the reservoir after the end of the rainy season. I see the photograph of a dam discharge scene hung on the wall of my office every day when I enter it for work. The picture was taken in 1981 as far as I know, and I wonder if you were working at the office at the time.
That’s right. I saw the picture when I happened to visit your office recently. I remember the date when the picture was taken. It was taken when the dam was discharged on July 12, 1981. I remember the dam discharge vividly because it took place a mere month after I was appointed to work in the dam management office. No one could imagine then that there would be an emergency dam discharge due to a major flood in just three years.
As I work for the operation of the dam, I’ve come to have a lot of questions about the dam discharge. It was before the management system was computerized as it is today. And I wonder how, through what process, the decision on dam discharge was made.
At the time I was just one of the new employees, and what I had to do was follow the directions of my senior officer faithfully. It was him who calculated and analyzed the inflow and outflow to and from the reservoir once the decision was made to open the sluice gate. It was then followed by the announcement on the evacuation of the residents inhabiting the area under the dam. Then I had to run around the streets of the town under the dam, guiding those who had not been informed of the dam discharge through the announcement to a safe place. The experience of the hard work is still vivid in my memory.
You must have gone through hard times considering that today the information on emergency situations is transmitted through a variety of modern means such as SMS, VMS, and Fax. In preparation for this meeting, I’ve read the Chronology of Soyanggang Dam Management kept at the time of your service. I found that the chronology was full of valuable traces of the times gone by just like ancient history books, and I was particularly interested in the records of the downpour of 1984. The records showed that the situation was really serious. Please tell me how you handled the difficult situation.
The rainy season of 1984 resulted in a lot of damages to many parts of Korea. The situation was aggravated by the arrival of typhoon Jun that dumped torrential rain even in the upstream of Soyanggang Dam. A total of about 400mm of rain poured down in just two days, September 1 and 2. Some of my colleagues left the office to visit the upstream of Soyanggang River but had to turn back because the road was flooded. As the rain continued and the reservoir’s water level continued to rise, we had to plan a discharge. But it was not easy to reach a final decision because we had to consider the situation of the areas below the dam.
It was probably because the dam discharge could cause additional damage to the capital area, which had already been hit by a flood, wasn’t it? You must have had a hard time before making the decision.
The water level of the dam kept rising, coming closer and closer to the flood mark, and we concluded that we had no more time to delay the decision. We were aware, of course, that earth- or rockfill dams, unlike concrete dams, were vulnerable to erosion caused by the overflow of water as they were made by piling natural materials such as earth and rubble. It can collapse if worse comes to worst. The entire staff of our office had to spend several sleepless nights, preparing for the procedures to be taken once the dam discharge decision arrived. It was at one o’clock in the morning of September 2 when the decision on emergency water discharge was made.
How was the situation after the discharge?
To our embarrassment, however, the water level did not drop even after the start of the discharge because the amount of inflow exceeded that of outflow. To make matters worse, a landslide occurred, which brought a large mass of earth and rock to cover the facility that was to function as a buffer at the time of water discharge, creating high waves that inundated the power plant. It led to power outage and loss of communication in addition to the road blockage, leaving us cut off from the outside world. I remember vividly how we tried to encourage each other as we ladled water out of our office and keep water out using rubble-filled rice bags. We had no spare food except for a box of instant noodles that our colleagues happened to have bought just in case as they returned to the office after failing to reach the upstream due to the road blockage. The noodles were at first a subject of derision among us as we thought them to be unsuitable for the circumstances but became priceless emergency food after the landslide that isolated us. I also remember the savory taste of the rice balls delivered by members of the women’s society of our company housing who bravely tried and successfully reached us despite the road blockage. Such event could never happen these days, right?
That’s right. I think I can understand the difficulty you went through in making decisions in those days largely because the speed of information processing was not like it is today as it was the time before the development of ICT and spread of personal computers. Today, advanced ICTs help collect and analyze information on the water level of the dam and amount of rainfall on a real-time basis while the automated flood analysis tools enable rapid decision making regarding the operation of the dam, including emergency water discharge. Today, we make further efforts to develop and improve cutting-edge technologies, such as digital twin and artificial intelligence, for more effective management of water and related facilities and preparation for climate change that causes extreme floods and droughts. Our efforts for effective water management and operation of the dam also aim to establish close cooperation with the local communities around the dam based on regular communications.
The passage of about forty years has really seen remarkable achievements. In our day, the office was run by about 100 employees, including security guards, who worked 24 hours a day in 3-4 shifts. I presume that many of the responsibilities we had are now fulfilled by unmanned, automated systems, aren’t they? There have also been external changes, I believe. In the past, the dam was regarded as a crucial state facility, banning acts of approaching it or taking pictures of the dam, power plant, and surroundings. There was, for example, a fort of an artillery unit at the place now occupied by the octagonal pavilion. I think it’s remarkable that today visitors can freely walk along the top of the dam. Regardless of such changes, one thing is certain: the prestige endowed on Soyanggang Dam for the citizens has never changed.
You’re absolutely right. For me personally it’s a great honor to join you in celebrating the 50th anniversary of Soyanggang Dam and have a talk with you about its history of ordeal and glory in which you and your colleagues played an important part for its development. I am confident that I will be here next year, too, preparing for a new period of half a century and that today’s meeting with you will remain a firm steppingstone for me to devote myself to the future glory of Soyanggang Dam. I hope that when the dam celebrates its centennial fifty years later someone working in the office where I do now will come find me and have a talk just like the one we have today. (laughter)
You’re absolutely right. For me personally it’s a great honor to join you in celebrating the 50th anniversary of Soyanggang Dam and have a talk with you about its history of ordeal and glory in which you and your colleagues played an important part for its development. I am confident that I will be here next year, too, preparing for a new period of half a century and that today’s meeting with you will remain a firm steppingstone for me to devote myself to the future glory of Soyanggang Dam. I hope that when the dam celebrates its centennial fifty years later someone working in the office where I do now will come find me and have a talk just like the one we have today. (laughter)
