China’s hydroelectric dam has brought in its wake a flood of concerns, especially in India, regarding its downstream impact

China’s largest hydroelectric dam on the Brahmaputra River (known as Yarlung Tsangpo in Tibet) recently became fully operational. The $1.5 billion 510 megawatt Zangmu hydroelectric dam has brought in its wake a flood of concerns, especially in India, regarding its downstream impact.

It is not for nothing that the Tibetan plateau is known as the ‘third pole’ — it is the largest repository of fresh water in the world, besides the Arctic and the Antarctic. The headwaters of many major rivers, flowing into some of the most populous regions of South and Southeast Asia, can be found in Tibet.

The prospect that the Tibetan plateau might turn into a desert is a frightening one indeed for the 1.4 billion people downstream who depend on it for freshwater. This dire warning is part of the findings of a recent report by the Chinese Academy of Sciences. Temperatures on the Tibetan plateau are projected to rise by up to 4.6 degree Celsius by the end of the century. The effects of global warming are already evident, with the plateau warming twice as fast as the global average.

There are fears that rapidly worsening desertification and rangeland degradation could convert Tibet’s water tower into a vast dust bowl. A recent study warns of increasing incidence of both floods and droughts in the Brahmaputra basin.

For all the anxiety over the downstream impact of China’s dams, India’s dialogue with China on the Brahmaputra has been treading water. There is for instance, little clarity on the effects of the 39 run-of-the-river projects — hydroelectric projects with minimal or no water storage — on the Yarlung Tsangpo and its tributaries.

Evidence is emerging that run-of-the-river projects are far from the benign interventions with little environmental effect that they are often projected to be. They tend to trap rich silt deposits, resulting in decreased downstream sediment flows. This will have significant implications for the fertility of the Brahmaputra basin, particularly for food security, as this sediment plays a much-needed role in replenishing eroded land. By 2050, more than one million people in the Ganges–Brahmaputra delta are likely to be directly affected by erosion and land loss, primarily because of decreased sediment delivery and rising sea levels.

India needs to look beyond its fixation with water diversion and raise the critical issue of water quality. Toxic runoffs are increasingly becoming a reality, with extensive mining activities on upper reaches of the river. A particular area of concern for downstream countries will be the environmental degradation facing Tibet’s ‘three rivers area’, comprising the Yarlung Tsangpo, Lhasa River and Nyang Chu basins in central Tibet.

One of the most intensely exploited areas in this region is the Gyama Valley, with its large polymetallic deposits of copper, molybdenum, gold, silver, lead and zinc. The Gyama valley is situated south of the Lhasa River, one of the five great tributaries of the Yarlung Tsangpo. Studies by Chinese scientists are pointing to the possibility of a high content of heavy metals in the stream, with sediments and tailings that could find their way downstream.

Understanding the cumulative impact of dam-building projects in a region that is ecologically fragile and densely populated will become increasingly critical. In the geodynamically active Himalayas, devastating earthquakes are an ever-present danger, with a recorded history going back to the 13th century. In 1950, for example, an earthquake with a magnitude of 8.6 ravaged India’s Assam state. While the epicentre of that earthquake was in Rima, Tibet, it was the Brahmaputra Valley that bore the most extensive damage.

The earthquake blocked several tributaries of the Brahmaputra and created a 30-foot high wall of water, destroying several villages in its wake. Dam-induced earthquakes cannot be ruled out. Research by Chinese scientists has shown that the Sichuan earthquake of 2008, which resulted in 80,000 casualties, could have been triggered by the Zipingpu Dam.

India and China need to be mindful of the bargains they make. For instance, data-sharing protocols between the two countries have tended to be commercial transactions, with India paying to receive flood-forecasting data. It is critical to ask to what extent such market-based mechanisms undermine the larger philosophical argument that water has an intrinsic, rather than merely instrumental, value.

India and China will also need to navigate normative tensions that stem from their positions as lower and upper riparians, respectively. Neither India nor China are signatories to the 1997 UN Watercourses Convention. The convention tends to validate contradictory principles among co-riparians.

Lower riparians generally pitch in favour of the ‘no significant harm’ principle — the duty of states to use international watercourses only in ways that do not harm other watercourse states. This principle protects prior and pre-existing uses of water. Upper riparians advocate a diametrically opposite interpretation, supporting the principle of ‘equitable use’, which grants equal weight to the needs of present and earlier uses. The institutional logjam has meant that a set of international rules regulating shared water resources has remained elusive.

As a lower riparian, it is in India’s interest to start a serious conversation with China on questions of benefit sharing, risk allocation and trade-offs on the Brahmaputra. For its part, China has assured India that ‘nothing will be done that will affect India’s interest’. But trust in a transboundary river basin is hardly built on such rhetoric. As co-riparians, India and China have no choice but to wade in and start building trust.

Nimmi Kurian is Associate Professor at the Centre for Policy Research, New Delhi, India.