Being built along river basins, Bhutan’s hydropower projects are vulnerable to flash floods and Glacial Lake Outburst Floods. As climate change increases the frequency and intensity of such events, the government says safety is being built into hydropower projects, from the planning and design phase to monitoring and emergency response after commissioning.
Bhutan’s rivers are the country’s greatest source of hydropower.
But they can also expose projects to natural hazards.
The government says flood safety has been part of hydropower development from the beginning. For newer projects, the design approach has become more rigorous.
Hydraulic structures are designed to safely accommodate extreme floods, including the Probable Maximum Flood, which means building structures to handle the absolute largest flood that is possible in that specific region.
And where GLOF threats exist, potentially hazardous glacial lakes and possible outburst scenarios are assessed as part of the Detailed Project Report.
Energy and Natural Resources Minister Sonam Tashi said, “Dams are designed to withstand hazardous glacial lakes and possible outburst scenarios. All these disaster risks have been incorporated into the design. We also have the dam safety guidelines, which we have followed and will continue to follow.”
He added that safety does not end when a project is commissioned. Bhutan’s Dam Safety Guidelines provide a framework for surveillance and inspection, with designated dam safety teams conducting inspections twice a year.
Where GLOF threats have been identified, such as in Mangdechhu, Chamkharchhu, and Punatshangchhu river basins, real-time Early Warning Systems are already in place and operational.
But authorities acknowledge that these measures cannot eliminate the risks posed by extreme natural events. Instead, the country’s approach is based on multiple layers of protection.
“The Punatsangchhu basin is particularly vulnerable. In case of a flood or GLOF from Thorthormi, the 140-kilometre distance to PHPA-II dam would provide time to manage and empty the river flow before the flood reaches the project,” said the minister.
As extreme weather events become more frequent, authorities say continued monitoring, early warning systems and timely action will remain critical to keeping Bhutan’s hydropower infrastructure and downstream communities safe.
Deki Lhazom
Edited by Phub Gyem
