Why couldn't the disaster of that day have been prevented?
On the 3rd, SBS 'I want to know' (hereafter 'Gal'), lit up the Gangnam flooding incident in August with the subtitle 'Death Hole - Why did the city become a weapon?'
The record heavy rain that fell in Seoul last August caused flooding in various parts of Gangnam.
And backflow was observed on roads all over Gangnam.
On the road, the manhole cover opened and water flowed back.
Something unimaginable happened.
Her brother and sister, who were returning from visiting her ill father, fell into a manhole.
Dozens of rescuers were sent in to find the siblings who disappeared in an instant, and searched the basement of the area, but it was not easy to find them.
And in the end, the two were found dead in different places, causing regret.
The cover of the manhole, which refers to the vertical hole connecting the ground and the basement, usually weighed over 100 kg and was difficult to open on purpose with a special locking device.
But why was the manhole cover opened so easily that day?
Seocho-gu Office, which manages the manhole, replied, "The terrain around Gangnam Station is low, and a lot of rainwater suddenly flowed in due to an instantaneous torrential rain.
However, as a result of the simulation, it was normal that the manhole at the accident site did not open.
However, due to the open manhole, experts guessed that the manhole was opened due to the situation where the sewage pipe networks did not work normally.
And many have raised suspicions about Gangnam's drainage system.
A rainwater pumping station or a watershed separation tunnel built to prevent flood damage did not work.
However, the city of Seoul raised doubts by claiming that these facilities did their job well enough.
The basic reason for repeated flood damage in Gangnam was the topography.
In addition, the underground drainage system failed to cope with the rain compared to the rapidly developed appearance.
Therefore, every year we spend a lot of money to try to improve it, but it turns out that the fundamental problem is not being improved because there are so many obstacles in the ground.
Japan, in a similar situation to ours, has invested 1.46 trillion won to build a deep tunnel under Tokyo to prepare for flood damage.
The deep tunnel was an enormous structure designed to store rainwater.
And it turned out that there was almost no flood damage after these facilities were installed.
An official said that if there were about six floods, the amount of damage would be equal to the cost of construction, and that the installation is having a great effect.
There was also a similar deep tunnel in Korea.
This is the Sinwol Tunnel installed in Yangcheon-gu, Seoul.
And it was confirmed that this heavy rain actually did much less damage than Gangnam, and had a great effect.
Gangnam-gu, which not only prepares for flooding, but also does not properly investigate the damage caused by flooding.
Residents were also very dissatisfied with the investigation by the local government.
In contrast, in Japan, it has been mandatory for two years to share the history of flood damage in real estate transactions.
In addition, by searching the disaster prediction map on the website of the Ministry of Land, Infrastructure and Transport, information about flooding was easily found.
Like Korea, where flood investigations are not conducted properly due to various interests, in Japan, it was difficult to establish a system due to various problems at first.
However, as it became mandatory to disclose it along with real estate information, it was confirmed that homeowners took steps to take proper waterproofing measures to prevent flood damage.
The city of Seoul has re-established countermeasures against flooding due to the damage caused by the heavy rain.
Accordingly, the city of Seoul promised to install a fall prevention facility in the manhole.
However, questions still remain as to whether this is a fundamental measure to prevent flood damage in Gangnam.
(SBS Entertainment News Editor Kim Hyo-jung)