Miscalculated Impact: Glacier Lake Flood Overwhelms Nepal Plant Despite Distance

[Anchor]

The developer of a hydropower plant in Nepal that was struck by a massive flood had predicted that the danger from glacial lakes would be limited due to the relatively large distance. However, that expectation proved wrong in the face of a flood of unimaginable power.

Reporter Choi Seung-hun has the story.

[Reporter]

This is the water-blocking facility of the Upper Trishuli-1 Hydropower Plant in the Rasuwa district of Nepal, filmed before the flood struck.

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

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

It cited floods caused by collapsing 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 lakes were located 30 to 60 km away from the water-blocking facility, it was expected that even when the flood was at its strongest, its impact 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 continued 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 mountain lake formed by melting glaciers burst out all at once, damaging some facilities under construction.

Doosan Enerbility, the builder, reinforced landslide and flood warning systems upstream and conducted evacuation drills twice this year.

Korea South-East Power 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 latest flood, which surged down so rapidly without leaving any 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: The glacial lake burst again, and as that water headed downstream, it triggered additional landslides and debris flows, going beyond the measures that had been established to a certain extent.]

Opinions are emerging that a new two- or three-tiered warning system utilizing satellites and other technologies is needed, going beyond the concepts of existing manuals.

[Video Editing: Won Hyeong-hee, Design: Jang Seong-beom]
※ Please note: This article was translated by AI and may contain errors.