Deep trust deficit stalling Siang mega dam in Arunachal Pradesh

Published 30 June 2026 · india

China’s rapid dam-building just across the border has prompted India to propose a massive countermeasure: an 11,000-megawatt dam on the Siang River in Arunachal Pradesh

China’s rapid dam-building just across the border has prompted India to propose a massive countermeasure: an 11,000-megawatt dam on the Siang River in Arunachal Pradesh. However, this strategic plan is locked in a bitter standoff with local indigenous tribes. While the ₹113,000 crore project is meant to stop devastating seasonal floods, secure India’s water rights, and lift the local farming economy, it remains stalled. With thousands of families facing displacement, the subcontinent’s largest planned dam cannot move forward until the government resolves a deep trust deficit with the people whose ancestral lands are on the line. The geopolitical threat and the Mighty Siang The race to control the Siang’s waters is driven by massive hydro-engineering projects currently being executed by China on the upper reaches of the river in Tibet. This includes a planned 60,000 MW “super dam” in Medog County, located just upstream of the Indian border. This upstream mega-project gives Beijing substantial control over transboundary water flows, presenting downstream India with two severe risks: flow disruption that triggers ecological devastation during dry months, and catastrophic artificial floods during sudden water releases. To counter these threats, the Government of India has prioritised the Siang Upper Multipurpose Project (SUMP). This initiative consolidates two earlier proposals from a 2013 Memorandum of Understanding (the 6,000 MW Stage-I and 3,750 MW Stage-II) into a single, massive storage-type dam near Geku village in the Upper Siang district. The primary focus of this project is safety, with power generation serving as a secondary benefit. Abhay Kumar Singh, Chairman and Managing Director of NHPC, has been quoted in the media as saying that the tentative investment for the project was around ₹1,13,000 crore and its height would be 280–300 metres. Siang project not just for generating power but mitigating flood risks posed by China: Arunachal CM Designed with an installed capacity of approximately 11,000 MW to 11,200 MW, the project will generate 47 billion kWh of electricity annually, making it the largest planned hydroelectric facility in the subcontinent.

The reservoir’s massive 9-billion-cubic-meter storage volume serves two key strategic purposes: establishing early physical “prior-use rights” to strengthen India’s legal claims under international transboundary water law, and creating a vital flood-buffer zone to absorb sudden upstream surges. The geography of the Siang basin To understand the scale of the project, one must trace the mighty Siang. Known upstream in Tibet as the Yarlung Tsangpo, the river originates in the Chemayungdung mountain range near Mansarovar at an elevation of 5,300 metres. It traverses 1,625 km parallel to the Himalayas, carves through the Grand Canyon, and enters India near Gelling, where it becomes the Siang. The river runs 197 km to its confluence with its largest right-bank tributary, the 170 km-long Shiyomi River (formed near Tato by the Shi and Yomi rivers). It continues for another 86.3 km to the Assam border, where it ultimately joins the Dibang and Lohit to form the Brahmaputra. The basin is fed by a dense network of smaller streams, including the high-altitude Yar Gyap Chu, which flows through the Mechuka Valley and holds deep religious significance for the local Buddhist populations. The Orchard Economy at risk Cradled by the alluvial-rich waters of the Siang river, the fertile delta region serves as Arunachal Pradesh’s primary economic backbone. For generations, the indigenous Adi and Galo communities have cultivated its slopes and valleys through terraced wet rice paddies and diverse agroforestry, earning steady household incomes between ₹4 and ₹7 lakh annually. The land, it turns out, is as generous as it is ancient. Under the State’s Horticulture Policy 2025-35, that generosity has translated into remarkable agricultural milestones, Arunachal Pradesh today stands as India’s largest kiwi producer, harvesting over 7,000 metric tonnes every year — and the first State to earn official organic certification for the fruit. Its mandarin oranges tell an equally impressive story: ranking second nationally at 84,000 metric tonnes, the prized varieties from Siluk and Dambuk have found their way to international shelves, including markets in the UAE. Meanwhile, in large cardamom, the State leads the entire northeastern region with a yield of 4,467 metric tonnes, a quiet dominance that speaks volumes about what this land, and its people, are quietly capable of.