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A landslide on the evening of 13 August 2026 pushed a sudden surge of water and debris into an under-construction tunnel of the 444 MW Vishnugad-Pipalkoti Hydroelectric Project in Uttarakhand's Chamoli district, near Mayapur in the Pipalkoti area.
Around 22 workers were inside at the time; seven were killed and 14 injured, with rescue teams accounting for 21 of them as operations continued.
The collapse created a cavity in the upper part of the tunnel, which is how the debris and water entered.
VPHEP is a run-of-the-river scheme on the Alaknanda, developed by THDC India Limited and financed by a US $648 million World Bank loan; construction work is being executed by Hindustan Construction Company.
The site is in the same district as the February 2021 Chamoli flash flood that destroyed NTPC's Tapovan-Vishnugad project, and the accident revives the question of tunnelling risk in the fragile Higher Himalaya.
A run-of-the-river scheme does not impound a large reservoir. It diverts part of the flow at a barrage or low dam, carries it through a long tunnel that gains height difference along the way, drops it through turbines, and returns it to the river further downstream — at VPHEP, about 18 km below the diversion. Because there is little storage, output tracks the river's own flow and falls in the lean season, which is why such projects are valued for peaking rather than firm base-load power. The trade-off that matters for the Himalaya is that the reduced dam size is bought with kilometres of tunnelling: VPHEP's head race tunnel alone runs 13.4 km through young, fractured, tectonically active rock. The environmental cost shifts from submergence to the stretch of river left with depleted flow, and the engineering risk shifts underground.
Simple Analogy: A storage dam is a bathtub; a run-of-the-river plant is a pipe fitted into a stream — it borrows the water briefly, uses the fall, and hands it back downstream.
| Project | River | Capacity | Developer | Known for |
|---|---|---|---|---|
| Vishnugad-Pipalkoti HEP | Alaknanda | 444 MW | THDC India Limited | The August 2026 tunnel debris surge; World Bank financed |
| Tapovan-Vishnugad HEP | Dhauliganga | 520 MW | NTPC Limited | Devastated by the February 2021 Chamoli flash flood, with workers trapped in its tunnel |
Developer of VPHEP; originally a joint venture of the Government of India (74.496%) and the Government of Uttar Pradesh (25.504%). Under a share purchase agreement of March 2020, NTPC acquired the central government's stake, so THDCIL is today a subsidiary of NTPC with the Uttar Pradesh government retaining 25.504%. It also operates the Tehri complex.
Executing the civil construction work at the project site
Financier of VPHEP through a US $648 million loan
The Alaknanda meets the Bhagirathi at Devprayag to form the Ganga; its five confluences — Vishnuprayag, Nandprayag, Karnaprayag, Rudraprayag and Devprayag — are standard prelims geography.
A rock-and-ice avalanche in the Rishiganga catchment sent a flood down the Dhauliganga, destroying the Rishiganga plant and flooding the tunnel of NTPC's Tapovan-Vishnugad project — the closest precedent for tunnel entrapment in this district.
Also in Chamoli district; the 2023 subsidence crisis put Himalayan tunnelling and slope stability at the centre of the hydropower debate.
Response to such incidents runs through the NDRF and SDRF under the Disaster Management Act, 2005, with the district administration as first responder.
GS Paper I > Geography — Physical geography of India, Himalayan rivers; GS Paper III > Infrastructure, energy and disaster management
General Awareness > Indian Geography and Current Events
General Awareness > Current Events of National Importance
A hydropower scheme with little or no storage that diverts flow through a tunnel and returns it downstream
The tunnel carrying diverted water from the intake to the powerhouse; VPHEP's is 13.4 km long
The tunnel returning water from the powerhouse to the river; VPHEP's is 3.04 km long
Electricity supplied during hours of highest demand, the role VPHEP is designed for in the Northern Grid