Fragile ecology, competing interests: The red flags in building Himalayan dams

Why in the News

A glacier collapse near the China Tibet border has triggered floods in Nepal that have killed over 1,100 people, with thousands still missing. The event has renewed expert concern about recent human made changes in a mountain system whose climatic conditions are shifting quickly. 13 hydropower plants, including several under construction projects, were affected. The tension is that dam and reservoir building is proceeding across the Himalayas as both an energy programme and a geopolitical signal, while the disasters it is exposed to cross national boundaries and no mechanism obliges the upstream state to share what it knows.

Why is the Himalayan system already fragile?

1. A naturally unstable mountain system: The Himalayas are prone to earthquakes, landslides, avalanches and flash floods before any human intervention is added.
2. The topography concentrates risk: The region carries lakes formed by melting glaciers, fast flowing rivers and steep slopes, in a zone highly vulnerable to strong earthquakes.
3. Climate change acts on the pace of natural processes: Temperature change affects the pace and frequency of snow melting and thawing, and of glacial lake outburst floods (GLOFs), which occur when water collected from melting glaciers overflows its containing barrier.
4. Attribution and risk are separate questions: Linking any single disaster directly to climate change still requires more scientific assessment, and the overall level of risk appears to be increasing.

How does infrastructure build up compound the toll?

1. Dams carry a genuine benefit: Dams and reservoirs regulate the flow of water and extend access to services for people living in remote regions.
2. Construction alters the geology: Building a dam disturbs the geology of the area and makes it more prone to earthquakes, and the drilling and tunnelling required for further projects extends that effect.
3. Damage runs through the assets themselves: The loss of hydropower plants in this flood dented both generation capacity and access to power.
4. Exposure has risen with use: Infrastructure build up and high tourist footfall together compounded the disaster’s toll.

How extensive is Himalayan hydropower now?

1. Across the Tibetan region: One recent study identified at least 193 dams built or planned across the wider Tibetan region since 2000.
2. In Nepal: A Nepal hydropower database lists more than 570 projects at different stages.
3. The largest single project: China is building a massive dam on the Yarlung Tsangpo, the upper course of the Brahmaputra, near Arunachal Pradesh.
4. A fault beneath it: In July, Chinese researchers flagged an active fault line, a fracture between two blocks of rock, directly beneath the Yarlung Tsangpo mega dam.

Why is Himalayan dam building also a geopolitical contest?

1. Infrastructure as a sovereignty marker: Chinese infrastructure building in Tibet is treated by China as a marker of sovereignty over Tibet, not only as an energy programme.
2. The response is more dams: India, Nepal and Bhutan have responded with their own set of dams, and India is helping Bhutan build a series of hydropower projects.
3. Signalling and counter signalling: The result is a pattern of signalling and counter signalling in which project decisions answer each other rather than answering the basin’s hydrology.

What is missing in transboundary cooperation?

1. No substantial ecosystem cooperation: There has been no substantial cooperation between China and Nepal, or between China and India, on managing the shared ecosystem.
2. The existing mechanism is narrow: Disasters in the 2000s prompted a memorandum of understanding between India and China in 2002, with an expert level mechanism on transboundary rivers created in 2005. That mechanism has to be expanded to cover other aspects such as GLOFs.
3. Transparency differs across the border: Nepal officially publishes fairly detailed project and licensing information. Chinese project level information exists but stays scattered across separate official documents and announcements rather than in a comparable consolidated public database.
4. No real time upstream data: There is no clearly established public system between China and Nepal for continuous, real time sharing of upstream river flow, reservoir operations or glacial lake conditions from Tibet.
5. Early warning fails at the border: Gaps in information and data sharing between countries complicate early warning for hazards that originate across a boundary.
6. No arbitration route: Downstream countries lack the consensus to build alliances that can deal with China, and there is no scope for international arbitration. Even a signed agreement would face a state that does not follow such international norms, as the South China Sea dispute shows.

What would stronger cooperation require?

1. Continuous data sharing: Cooperation would necessarily include continuous sharing of hydrological, weather and climate data across the boundary.
2. Paying for upstream observation: Where sustained monitoring carries a cost, downstream countries could co invest in upstream observation systems or pay for specialised datasets, creating a model that benefits both sides.
3. Standing operational machinery: Automated public warning systems, joint scientific studies and regular emergency exercises would complement the data arrangements.
4. A landscape rather than a national frame: A nation state centric, container approach does not fit the Himalayas, since these disasters do not confine themselves within national boundaries and their ramifications run across the landscape.

Challenges to hydropower expansion in the Himalayas

1. Projects sit in the highest seismic risk zones: Much of the Himalayan arc falls in seismic zones IV and V, so a design earthquake is a live engineering assumption rather than a remote one. Eg. The 2011 Sikkim earthquake damaged structures at the Teesta III project and halted work.
   The Fix: Make site specific seismic hazard assessment and independent design review a published precondition for financial closure, not a post clearance formality.
2. Sediment load shortens the working life of a project: Himalayan rivers carry among the world’s highest silt loads, which abrades turbines and fills reservoirs faster than design assumptions allow. Eg. Run of the river plants on the Alaknanda and Bhagirathi shut down repeatedly during the monsoon for desilting.
   The Fix: Require measured basin sediment yield data in the detailed project report and size desilting capacity against it rather than against a regional average.
3. Cascade layouts convert one failure into several: Projects built in series on the same river mean an upstream breach delivers debris and water straight into the next structure. Eg. The 2021 Chamoli flood destroyed the Rishiganga project and then struck the Tapovan Vishnugad project downstream.
   The Fix: Assess clearances at the level of the whole river cascade, so cumulative and cascading failure is evaluated once rather than project by project.
4. Tunnelling destabilises slopes and drains aquifers: Long headrace tunnels cut through fractured rock, dewater springs and remove support from the slopes above. Eg. Land subsidence in Joshimath in 2023 followed years of tunnelling and construction in the same valley.
   The Fix: Publish pre construction and post construction spring discharge and slope movement monitoring for every tunnelled project, with construction halted on a defined trigger.
5. Rehabilitation is settled before the risk is understood: Displaced communities are resettled onto land whose hazard exposure has not itself been mapped. Eg. Resettlement colonies for Himalayan projects have been sited on debris fans and old landslide zones.
   The Fix: Require the resettlement site to carry its own hazard clearance before the displacement award is finalised.

Conclusion

Himalayan risk now runs through infrastructure as much as through geology. The two positions that cannot both hold are that dams are national assets worth building at scale and that the floods which destroy them cross three borders within minutes, with no obligation on the upstream state to say what is coming. Data sharing, not engineering standards, is the binding constraint on early warning. The concrete thing to watch is whether the India China expert level mechanism is widened past monsoon river flow data to cover glacial lake and reservoir conditions.

Matching Previous Year Question

“[2023, GS3, 10 marks] Dam failures are always catastrophic, especially on the downstream side, resulting in a colossal loss of life and property. Analyze the various causes of dam failures. Give two examples of large dam failures.”