"30 to 60 km Away, So Flood Impact Will Decrease"... Mistaken Expectations

[Anchor]

The developer of a hydropower plant in Nepal that was hit by a massive flood had predicted the risks of a glacial lake, concluding that the impact would be minimal because it was located relatively far away. However, due to the unimaginable power of the flood, that expectation proved to be wrong.

Reporter Choi Seung-hun has the details.

[Reporter]

This is the diversion dam facility of the Upper Trishuli-1 hydroelectric power plant in the Rasuwa district of Nepal, filmed before the flood struck.

It is a core facility of the power plant that blocks river water and channels it into the underground tunnel entrance. It is estimated that about 90% of this facility was destroyed in the recent flood.

This disaster management plan was drawn up in 2018 by Nepal Water and Energy Development Company (NWEDC), a local project corporation where Korea South-East Power (KOEN) is the largest shareholder.

It cited floods caused by the collapse of glacial lakes as a major natural disaster in Nepal.

It also warned of the risk of cross-border floods, noting that half of the Trishuli River basin is in China, making monitoring difficult.

However, because the glacial lake was located 30 to 60 km away from the dam facility, it was expected that even the most severe impact of the flood would be significantly reduced by the time it reached the site.

Consequently, it was determined that it would not affect the scale of the monsoon floods reflected in the design.

This assessment was maintained even in the supplementary environmental impact assessment conducted by the same company in June of last year.

However, in July of last year, a flood occurred when water from a lake on the mountain, formed by melting glaciers, burst down all at once, damaging some facilities under construction.

Doosan Enerbility, the constructor, reinforced the landslide and flood warning system upstream and conducted evacuation drills twice this year as well.

KOEN also visited Nepal multiple times starting in October of last year to inspect the site conditions.

Nevertheless, the construction site suffered massive damage from this recent flood, which surged down so rapidly without time to escape that the downstream river water level soared by up to 9 meters in just 30 minutes.

[Hwang Seok-hwan / Research Fellow, Korea Institute of Civil Engineering and Building Technology (KICT): The glacial lake burst again, and as those waters traveled downstream, they triggered additional landslides and debris flows, exceeding the scope of the measures that had already been established to a certain extent.]

Opinions are emerging that new, dual and triple warning systems utilizing satellites and other technologies are needed, going beyond the concepts of existing manuals.

(Video Editing: Won Hyung-hee, Design: Jang Sung-beom)
※ Please note: This article was translated by AI and may contain errors.