More Than 1,100 Himalayan Hydropower Projects Raise Fears for Asia’s Water Tower

The Himalayas, known as Asia’s water tower, now host more than 1,100 hydropower projects that are operating, under construction or planned. The concentration of facilities is drawing renewed scrutiny after devastating floods and landslides struck the Nepal-China border region.

The Hindu Kush-Himalaya and Tibetan Plateau feed 11 major rivers and supply water to as many as 3 billion people. Their glaciers, steep terrain and abundant year-round water make the region highly attractive for hydropower. Nepal alone operates 166 plants producing 3,167 megawatts and plans to expand to 538 plants with a combined capacity of 10,265 megawatts.

“

Important ecosystem components will be seriously damaged if development continues in the same manner as now.

But the region also faces recurring earthquakes, glacier loss, floods and landslides. In 2021, a collapse of ice and ground in India’s Uttarakhand state damaged four hydropower plants, including the Rishiganga facility. A glacial lake outburst flood in Sikkim in 2023 killed more than 170 people and destroyed the 1,200-megawatt Teesta 3 plant. Nepal’s 2015 earthquake killed more than 9,000 people and disrupted 30% of the country’s hydropower supply.

“

A small project itself may struggle to affect the surrounding environment, but when multiple projects are concentrated, they can help push the overall environment beyond a critical threshold.

Researchers say the danger lies not only in individual projects but in their cumulative impact. South Korean researcher Hwang Seok-hwan said several small projects in a confined area could push the wider environment beyond a critical threshold. Michigan State University researcher Yadu Pokhrel similarly warned that dense clusters of small, run-of-river plants could cumulatively deplete river flows, cause flooding, fragment wildlife habitats and alter water regimes.

The World Bank’s International Finance Corporation, which led private investment in Nepal’s Upper Trishuli-1 project, issued a cumulative-impact assessment in 2020. It identified habitat fragmentation, shrinking watershed areas, water shortages and rising landslide risks in the Trishuli basin. At the time, six plants were operating, seven projects were under construction and at least 23 more were planned. The South Asia Network on Dams, Rivers and People said authorities had failed to address the risks linked to disasters, glacial floods, cross-border effects and climate change.

“

Small and run-of-river hydropower projects, when densely developed, can cumulatively cause river-flow depletion, flooding, wildlife-habitat fragmentation, changes in flow regimes and impacts on conservation areas.