Arunachal Pradesh State Cabinet approves panel for survey of Siang mega dam
The Arunachal Pradesh State Cabinet approved the constitution of an Empowered High-Level Committee to guide and coordinate the Pre-Feasibility Report (PFR) survey for the proposed Siang Upper Multipurpose Project (SUMP) in Siang and Upper Siang districts.
The project is a storage-based hydropower scheme on the Siang river, the name given to the Brahmaputra as it enters Arunachal Pradesh from Tibet, with a proposed capacity of around 11,000 MW.
The state government stated the panel's purpose is to ensure the survey proceeds in a transparent, peaceful, and people-centric manner, amid local apprehensions over displacement and submergence.
The project was originally accorded "National Project" status by the Union Government in 2008, reflecting its designation as a strategically and developmentally significant hydel scheme.
The Brahmaputra river system and the Siang
The Brahmaputra originates as the Yarlung Tsangpo near the Chemayungdung glacier in the Kailash range of Tibet, flows eastward across the Tibetan plateau, then takes a sharp southward turn — the "Great Bend" — around the Namcha Barwa massif before entering India through Arunachal Pradesh, where it is known as the Siang. After being joined by the Dibang and Lohit rivers in Assam, it takes the name Brahmaputra proper and eventually merges with the Ganga system in Bangladesh (as the Jamuna) to form the Ganga-Brahmaputra-Meghna delta.
Key Details
- The Brahmaputra is unusual among major Indian rivers for changing names multiple times across its course (Yarlung Tsangpo, Siang/Dihang, Brahmaputra, Jamuna) and is conventionally referred to as a "male" river in Indian nomenclature.
- It is a trans-boundary river flowing through China (Tibet Autonomous Region), India, and Bangladesh, making it central to India's riparian relations with both neighbours.
- The river's steep gradient drop through the Himalayan gorge near the Great Bend gives this stretch exceptionally high hydropower potential, which is the basis for large dam proposals on both sides of the border.
The Siang Upper Multipurpose Project is sited on precisely this high-gradient stretch of the river soon after it crosses into Indian territory, which is also cited as a reason for its strategic significance relative to hydro-engineering activity upstream in Tibet.
India-China trans-boundary river cooperation (or its absence)
India and China have no binding water-sharing treaty over the Brahmaputra/Yarlung Tsangpo, unlike India's treaties with Pakistan (Indus Waters Treaty, 1960) or Bangladesh (Ganga Waters Treaty, 1996). Cooperation is limited to a 2006 Expert Level Mechanism (ELM) for discussing trans-border river issues and periodically renewed Memoranda of Understanding on sharing hydrological (flood-season) data for the Brahmaputra and the Sutlej.
Key Details
- The Brahmaputra hydrological data-sharing MoU was first signed in 2002 and has been periodically renewed; data-sharing has been interrupted in the past during periods of bilateral tension, underscoring its non-institutionalised nature.
- Unlike the Indus Waters Treaty, 1960 (a World Bank-brokered, legally binding water-allocation treaty with a Permanent Indus Commission and dispute-resolution mechanism), the India-China ELM is a diplomatic dialogue mechanism with no arbitration or legally binding entitlement.
- China has announced its own large hydropower project on the Yarlung Tsangpo near the Great Bend in Tibet, upstream of Arunachal Pradesh, envisaged as a cascade of dams.
Upstream dam-building activity in Tibet, combined with the absence of a binding water-sharing framework, is cited as part of the rationale for India's own storage project on the Siang — both to assert an upstream water-use claim and to provide flood-moderation storage against sudden flow variations from upstream projects.
Environmental and forest clearance process for hydel projects
Large hydropower projects in India require statutory clearances before construction: environmental clearance under the Environment Impact Assessment (EIA) Notification, 2006 (issued under the Environment (Protection) Act, 1986), and forest clearance under the Forest (Conservation) Act, 1980 (renamed the Van (Sanrakshan Evam Samvardhan) Adhiniyam, 1980 after a 2023 amendment) where the project involves diversion of forest land. A Pre-Feasibility Report (PFR) survey is typically among the first technical steps, informing later Detailed Project Reports and the formal EIA process, which includes public hearings.
Key Details
- The EIA Notification, 2006 categorises river valley/hydel projects as "Category A" (requiring Union-level environmental clearance via an Expert Appraisal Committee) or "Category B" depending on capacity/area thresholds, and mandates public consultation, including public hearings in the affected district.
- The Forest (Conservation) Act, 1980 requires prior Union Government approval for diversion of forest land to non-forest use; large hydel reservoirs in hill states typically involve substantial forest submergence.
- Arunachal Pradesh is not a Fifth Schedule state, so the Panchayats (Extension to Scheduled Areas) Act (PESA), 1996 does not apply there; land and forest matters are instead governed by state-specific regulations, general environmental/forest law, and the Bengal Eastern Frontier Regulation, 1873 (the Inner Line Permit regime).
The newly approved committee is meant to steer the PFR stage of the project, which precedes the statutory EIA and forest-clearance processes that will determine whether, and on what conditions, the dam can proceed.
- Siang Upper Multipurpose Project (SUMP): proposed capacity approximately 11,000 MW, located in Siang and Upper Siang districts, Arunachal Pradesh.
- Declared a "National Project" by the Union Government in 2008.
- The Brahmaputra is called the Yarlung Tsangpo in Tibet, the Siang/Dihang in Arunachal Pradesh, and the Brahmaputra in Assam; it becomes the Jamuna in Bangladesh.
- India-China Brahmaputra hydrological data-sharing MoU: first signed 2002, periodically renewed; no binding water-allocation treaty exists between the two countries, unlike the Indus Waters Treaty, 1960 with Pakistan.
- Governing clearance framework for the project: EIA Notification, 2006 (under the Environment (Protection) Act, 1986) and the Forest (Conservation) Act, 1980, for environmental and forest clearances respectively.