Siang Upper Multipurpose Project: Key Details, Location, and Significance

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The proposed **₹113,000 crore** **Siang Upper Multipurpose Project (SUMP)** faces strong opposition from local indigenous **Adi** and **Galo** tribes in **Arunachal Pradesh**.
This opposition stems from serious displacement concerns and a growing trust deficit between the local communities and the authorities.

The **Siang Upper Multipurpose Project (SUMP)** is a planned mega-hydroelectric and flood-control project with a targeted installed capacity of **11,000 MW to 11,200 MW**.
It combines two previous project plans into a single storage reservoir standing **280 to 300 meters** high.
This massive reservoir will hold **9 billion cubic meters** of water and generate **47 billion kWh** of clean electricity every year.

The project is located near **Geku** village in the **Upper Siang** district of **Arunachal Pradesh**.
The main river for this project is the **Siang River**, which enters India near **Gelling** after originating as the **Yarlung Tsangpo** at **5,300 meters** altitude in the **Chemayungdung** mountain range near **Mansarovar** in Tibet.
After flowing **197 km**, the Siang joins its largest right-bank tributary, the **Shiyomi River**, and later meets the **Dibang** and **Lohit** rivers in Assam to form the **Brahmaputra River**.
The high-altitude **Yar Gyap Chu** stream flowing through the **Mechuka Valley** also feeds into this river basin.

The project is currently stalled due to widespread local opposition.
Grassroots movements led by the **Siang Indigenous Farmer's Forum (SIFF)** and **Adi Banne Kebang (ABK)** have physically stopped the executing agency **NHPC** from carrying out pre-feasibility surveys.
Public resistance spans across three targeted locations including **Ugeng**, **Dite Dime**, and **Parong**, making village submergence and displacement estimates highly disputed.

The river flows through the **Yarlung Tsangpo Grand Canyon**, featuring steep gorges that offer tremendous hydropower potential but are ecologically sensitive.
The region lies in an earthquake-prone **eastern Himalayas** zone where landslides can block rivers and cause sudden downstream flooding.
Downstream alluvial plains contain rich fertile soil supporting a flourishing orchard economy centered on **kiwi**, **mandarin oranges**, and **large cardamom**.
Unpredictable monsoon patterns trigger major variations in river flow, causing heavy soil erosion and destruction of agricultural land.

Building water infrastructure on the Siang strengthens India's **prior-use claims** under international water law against upstream developments.
The large reservoir can absorb excess floodwaters, significantly reducing downstream flood risks for **Arunachal Pradesh** and **Assam**.
The project will produce renewable energy, expand irrigation, generate local employment, and turn **Arunachal Pradesh** into a green energy hub.