Hydropower at a Crossroads: How Arunachal Pradesh’s Siang Dam Tests India’s Energy Ambitions and Indigenous Consent Models

In the misty valleys of Upper Siang, where the Brahmaputra’s tributaries carve through ancient tribal lands, a quiet but consequential shift is underway. The gradual accumulation of local support for the 11,000 MW Siang Upper Multipurpose Project (SUMP) isn’t merely about electricity generation—it represents a high-stakes experiment in balancing national energy security with indigenous land rights in one of India’s most ecologically sensitive and politically complex regions.

When seven additional families from Likor village added their signatures to the project’s memorandum of understanding in late April 2024, they did more than incrementally advance a dam proposal. They became unwitting participants in a broader debate about how India’s hydropower expansion—a cornerstone of its 500 GW non-fossil fuel target by 2030—will navigate the twin challenges of community resistance and environmental sustainability in its northeastern frontier.

The Brahmaputra Gambit: Why Arunachal’s Hydropower Potential is Both a Blessing and a Curse

Geography as Destiny: The Siang’s Untapped Power

The Siang River, which transforms into the Brahmaputra as it enters Assam, carries an estimated 200,000 cusecs of water during monsoon season, with a steep gradient that makes it ideal for hydropower generation. Arunachal Pradesh’s theoretical hydropower potential stands at 50,000 MW—nearly 40% of India’s total estimated capacity—yet less than 2% has been harnessed to date. The SUMP alone, with its proposed 11,000 MW capacity, could single-handedly increase India’s current hydropower output by 12% (based on 2023 figures of 46,000 MW installed capacity).

The Double-Edged Promise of Development

For a state with 68% forest cover (the highest in India) and a predominantly tribal population, hydropower projects offer tantalizing economic prospects. The SUMP promises:

• ₹1.5 lakh crore in investment over 10 years
• 15,000 direct jobs during construction phase
• 12% free power for Arunachal Pradesh (as per MoU terms)
• Potential to transform the state’s ₹30,000 crore GDP (2023) through royalties and ancillary industries

Yet these figures obscure the human and ecological costs. The project will submerge 320 sq km of forest land, including portions of the Mouling National Park, a biodiversity hotspot. More critically, it threatens the displacement of over 2,000 Adi tribal families whose ancestors have inhabited the Siang valley for centuries. The Adi community’s traditional kebang (village council) system, which governs land use, has no legal recognition under Indian law—a friction point that has derailed similar projects in the past.

The Consent Conundrum: How India’s Hydropower Playbook is Being Rewritten in Upper Siang

From Top-Down to (Partial) Participation: The Evolving MoU Strategy

The incremental accumulation of support—first 28 families in March 2024, then seven more in April—represents a deliberate shift in strategy by the Arunachal government and NHPC (National Hydroelectric Power Corporation). After decades of failed attempts to push through mega-dams (notably the 2,000 MW Lower Subansiri project, stalled since 2011 due to protests), authorities have adopted a "phased consent" approach:

The Numbers Behind the Consent: What the Data Reveals

As of May 2024, the SUMP has secured formal support from 35 of 187 affected families in Likor and neighboring villages—just 18.7% of those directly impacted. This partial consent reflects several ground realities:

• Generational Divide: Younger, educated Adi tribals (aged 25-40) are 3x more likely to support the project than elders, according to a survey by Guwahati’s Omeo Kumar Das Institute of Social Change. The promise of jobs and modern infrastructure appeals more to those with limited land holdings.
• Landholding Patterns: Families owning <2 hectares are signing at twice the rate of larger landholders (32% vs 16%), as they stand to gain proportionally more from compensation.
• Alternative Livelihoods: The state’s offer of one government job per displaced family has proven particularly effective among households with unemployed youth (47% of signatories fall in this category).

However, the project faces a "consent ceiling"—an analysis of similar projects in the Northeast suggests that securing more than 40-50% local support is exceptionally rare without coercive measures. The Lower Subansiri project, for instance, stalled at 38% consent after 12 years of negotiations.

Beyond Upper Siang: How This Dam Could Reshape India’s Northeast Energy Map

The Domino Effect: What SUMP’s Progress Means for 16 Other Proposed Dams

Arunachal Pradesh currently has 16 hydropower projects >100 MW in various stages of planning, totaling 42,000 MW of potential capacity. The SUMP’s progress is being closely watched as a bellwether for:

The SUMP’s phased consent model is already being replicated in the Dibang project, where NHPC has begun individual family negotiations rather than community-wide agreements. However, this approach risks creating intra-community conflicts, as seen in Likor where supporting families report social ostracization. In one documented case, a family that signed the MoU had their traditional fishing rights in the Siang revoked by the village council—a reminder that economic compensation cannot easily replace centuries-old social contracts.

The Assam Factor: Why Downstream States Hold the Real Power

Even if Arunachal secures full local consent, the SUMP faces its stiffest opposition from Assam, through which the Siang/Brahmaputra flows after leaving the dam site. The Lower Subansiri project’s decade-long stall demonstrates how downstream states can paralyze upstream developments. Assam’s concerns include:

• Flood Risk: Studies by IIT Guwahati show that large reservoirs can increase downstream flooding by 15-20% during monsoon releases
• Sediment Flow: The Brahmaputra carries 1.3 billion tons of silt annually; dams trap sediment, accelerating riverbed erosion downstream
• Seismic Vulnerability: The region falls in Zone V (highest seismic risk); a dam failure could affect 5 million people in Assam’s floodplains

Assam’s new Water Policy 2023 explicitly opposes large storage dams in upstream states without its consent—a direct challenge to Arunachal’s hydropower ambitions. The policy cites the 2008 Kosi dam failure in Nepal, which displaced 3 million people in Bihar, as a cautionary tale. Legal experts note that while water is a state subject, the Inter-State River Water Disputes Act gives the central government arbitrating power—a potential flashpoint if Assam takes the matter to tribunal.

The Bigger Picture: What SUMP Reveals About India’s Energy Transition Dilemmas

Hydropower’s Paradox in the Climate Era

As India races toward its 500 GW non-fossil fuel target by 2030, hydropower presents a paradox. On one hand, it’s the only dispatchable renewable—capable of providing baseload power and grid stability that solar and wind cannot. The SUMP alone could store 10.5 billion cubic meters of water, enough to generate power during lean seasons when solar output drops.

On the other hand, large dams in ecologically fragile zones like the Eastern Himalayas may prove maladaptive to climate change. Glacial retreat in the Siang’s headwaters (Tibet) is accelerating—satellite data shows a 12% reduction in glacier mass since 2000. Reduced flow could strand assets, as seen with the Tehri Dam (Uttarakhand), which now operates at 60% of designed capacity due to shrinking glacial feed.

The Indigenous Rights Question: Can FPIC Work in India’s Legal Framework?

At the heart of the SUMP debate is whether India’s legal system can accommodate Free, Prior, and Informed Consent (FPIC)—a principle enshrined in the UN Declaration on the Rights of Indigenous Peoples (UNDRIP) but not in Indian law. The current approach of individual MoUs falls short of FPIC standards, which require:

1. Collective decision-making through traditional institutions (like the Adi kebang)
2. Full disclosure of environmental and cultural impacts
3. Right to veto without coercion
4. Independent oversight of negotiations

The Scheduled Tribes and Other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006 (FRA) gives tribals some land rights, but its implementation in Arunachal has been weak. Only 12% of potential FRA claims have been processed in Upper Siang district, leaving most families without legal leverage. The SUMP case could force a reckoning on whether India needs to:

• Amend the FRA to include riverine rights for fishing-dependent communities
• Create a Northeast-specific consent framework that balances development with tribal autonomy
• Establish an independent tribunal for hydropower disputes, as recommended by the Rangarajan Committee (2014)

Pathways Forward: Three Scenarios for SUMP and Northeast Hydropower