● The best of Geumgang... Yongdam Dam in

Jinan, Jeonbuk Yongdam Dam in Jinan, Jeollabuk-do is located in the uppermost region of the Geum River. When water flows from the dam, it flows through Muju, Jeollabuk-do, Geumsan, Chungcheongnam-do, Youngdong, Chungbuk, and Okcheon. On the 8th, the discharge of Yongdam Dam hit these four municipalities by water bombs. It was investigated that 204 houses and 745㏊ of agricultural land were submerged and damaged.

As it is said that water is scarier than fire, the wounds Suma scratched were terrible. The house has become muddy, and the house and household items are also wet and ruined, so the victims have little to use right away. As the raging river swept away, the peaceful home was quickly turned into a field. Five days have passed since the flood, but the residents said they still couldn't believe the terrible reality.

● One hour after the

evacuation order was issued, 2,900 tons were released per second . The evacuation order was given to the residents of Jewon-myeon and Buri-myeon, Geumsan-gun, Chungcheongnam-do at 11 am on the 8th. Earlier, the Governor of Yongdam Dam of Korea Water Resources Corporation informed Geumsan-gun Office at around 10:30 that the amount of discharge would be increased from 1,500 tons per second to 3,200 tons per second. The army, frightened, advised residents of the area concerned about flooding to evacuate to a safe place.


Yongdam Dam discharged 2,900 tons per second at 12 o'clock in the daytime as announced. Discharged at 2:50 am was 1,000 tons, increased to 1,490 tons at 9:40 am and 2,500 tons at 11:10 am, followed by a triple increase in 9 hours. The large stream spewed out by the dam arrived in just two hours, and it swept away the lives of Geumsan residents.


The average rain in Geumsan on the 8th was 74.9mm, and the average precipitation on the previous day was 72.3mm. The residents argued that the discharge of Yongdam Dam was the direct cause of the flood, saying that such rain could not cause flood damage. It is not a natural disaster, but a talented person who has greatly increased the amount of discharge.


What happened to Yongdam Dam on the day of the flood? The Geumgang Flood Control Office is publishing the operation data of Daecheong Dam and Yongdam Dam on the Internet in real time. Yongdam Dam first discharged on the 14th of last month. Starting from 90 tons per second at 2:10 pm, gradually increasing and decreasing to about 200 tons, adjusting the amount of discharge until the 30th. It seems that the water level was not exceeded 261.5m during the flood season. The water level limit during the flood season is the standard that the dam water level should be operated below 261.5m for 3 months from June 21 to September 20 when there is a risk of flooding due to heavy rain. The planned flood level of Yongdam Dam is 265.5m. The planned flood level is the limit of rainwater that a dam can contain as much as possible as a standard for storing and exporting when it rains. Except for 3 months of flood season, the normal full water level is 263.5m.

● The flood limit

has been exceeded, but the flood limit of the Yongdam Dam in response to the rear north exceeded the standard level at 12:40 on the 30th of last month at 261.53m. After that, the flooding damage did not go below the limit until the 8th. It should have been prepared for the inflow of rainwater into the dam by gradually increasing the amount of discharge to lower the water level, but it was not.

In particular, the water level at 12 o'clock on the day before the water crisis was 262.45m, and 1962 tons of water per second entered the dam, but only 297 tons per second, 15% of the water flowed through the water gate. At 2:10 pm, the amount of inflow increased significantly to 3,103 tons per second, but the amount of discharge was only 293 tons, 9% of the inflow. At 3:20, an hour later, the inflow amount was 4,205 tons, and the discharge amount was 494 tons, 12%. At 3:40, 4872 tons of water increased, but the discharge was 497 tons, which remained at 10%. At 4:10 pm, compared to the inflow of 3,986 tons, the discharge amount was 16%, and 621 tons were flowed out of the dam.


Even though big water came into the dam, the golden time was missed. Meanwhile, the water level of the dam rapidly increased by 1.3m for 4 hours from 12:262.45m to 4:10pm, reaching 263.73m, reaching 261.5m of the flood limit. It was in a state exceeding 2m or more.

After that, the amount of discharge was gradually increased, and at 12 o'clock on the 8th, it discharged 2,900 tons, which is 72% of the 4,19 tons of inflow, but it was not enough to lower the water level. Brought.


According to the dam operation guidelines, when the water level exceeds the limit during the flood season, the amount of discharge must be adjusted to lower the water level. However, it is a pity that it would have prevented the water crisis if we had responded by increasing the amount of discharged even when large water entered the day before the flood, while the water level had been exceeded a week before the flood damage.

● The failure to discharge was due to concerns over precipitation and flooding of small bridges. In a

briefing by the Ministry of Environment on the 12th, the Korea Water Resources Corporation attributed the failure to control the amount of discharge to the weather. Initially, for two days on the 7th and 8th days, a maximum of 300 mm of precipitation was forecast in Jinan and Jangsu, which are the dam basins, but in fact, an average of 380 mm fell and a maximum of 446 mm of rain in the Jangsu area was forced to increase the amount of discharge rapidly. Regarding the failure to manage the amount of discharge below the limit, they claimed that there were complaints from some residents asking to prevent the flooding of Sewol Bridge, a small bridge.


The Sewol Bridge is a small bridge made by laying a Hume pipe in a river to allow water to flow and then covering the pipe with cement so that people and vehicles can pass by. This bridge is mainly used by residents who go to and from the farmland across the river, and it is often submerged in the rain when the river rises during the rainy season.

The water resources corporation's explanation of the failure to control the amount of discharge attributable to the weather and concerns about flooding of a small bridge is dismal. Since the first flood damage occurred after the dam was completed in 2001, another flood damage can be prevented by re-checking the manual. Discharge control measures can be devised only when a detailed analysis of the amount of discharge per second that can cause flooding damage to the downstream area is presented. A flood victim in Jewon-myeon, Geumsan said, “It was the first time that half of the house was submerged in the water, saying that the river did not overflow even during the typhoon cicada, which caused great damage in the fall of 2003. If you are stingy in acknowledging your mistakes, poor measures will come out and you will have to worry about the second and third flood damage. Moreover, it is a reality that the pattern of precipitation in global villages including Korea is changing beyond the climate. The lost trust can be regained when concrete measures are established based on a cold and honest analysis, and the operation is faithful to the principles and basics.

The answer is already there. Practice is always a problem.