The Brahmaputra has been the lifeline for many in Assam and Arunachal Pradesh, helping 80 per cent of the 27 million people in these two states pursue agriculture.
SD Mishra wrote in Rivers of India, "The Brahmaputra, the river normally neglected by most writers, is probably the most significant in the present day geopolitical context." Researchers like DC Goswami, head of Guwahati University's environment science department, say the river and its tributaries constitute the most powerful fluvial system in India. It also possesses one-third of India's hydro-power potential.
This potential would disappear if China proceeds with its reported plan to divert the water of Tsangpo at the 'Great Bend'—where the river makes a sharp bend southwards—to feed that country's parched northern regions. In such a case, agriculture and water resources experts in Assam say China would control the flow of water into northeastern India and Bangladesh.
"Diversion or damming of the Tsangpo would affect the ecological balance of the region; besides, the route the Tsangpo-Brahmaputra takes is highly seismic," says Goswami. There is also the danger of a "double blow"—China withholding water for power generation and irrigation during the dry season and releasing excess water during the rainy season.
The nutrient-rich sediments that enrich the soil of the Brahmaputra valley would also be retained in the proposed Chinese reservoirs, thereby rendering the downstream land barren over the years.
The impact would perhaps be felt most by biodiversity hotspots like the Kaziranga National Park, home of the world's largest number (1,855) of one-horned rhinoceroses, and the Pobitora Wildlife Sanctuary, which boasts of the largest concentration of the animal. Both depend on the Brahmaputra to be cleansed of weeds and 'recharged' during 'normal' floods.
Too much water or too little would go a long way in destroying Kaziranga's grassland, the rhinos' source of sustenance.