Indian government has raised concerns about possible downstream impact of project
China has started damming the middle reaches of the Brahmaputra river, or the Yarlung Tsangpo as it is known in Tibet, to begin construction on a 510 MW hydropower project that has raised concerns in India.
The government for the first time revealed that it has, since November 8, begun damming the Tsangpo's flow to allow work to begin on the hydropower project at Zangmu. This is the first major dam on the Brahmaputra and has been billed by the Chinese government as a landmark hydropower generation project for Tibet's development.
A news report on Monday said the “closure of the Yarlung Zangbo river on November 12 marked the beginning of construction.” Work is expected to continue beyond 2014, when the first set of generators will be put into operation. The total investment in the project is 7.9 billion yuan ($1.2 billion).
The Indian government has raised concerns about the possible downstream impact of this project during talks with China earlier this year. Chinese officials have assured their Indian counterparts that the project would be “run of the river,” having little impact downstream.
China has said that its projects were only for hydropower generation, and were neither storage projects nor designed to divert the water.
Officials at India's Ministry of External Affairs have, however, voiced frustration over China's general lack of willingness to share information regarding the Zangmu project, meaning they had little means to verify claims on the specific construction plans and impact on flows.
According to Ramaswamy R. Iyer, former Water Resources Secretary of the Government of India, for India “the point to examine would be the quantum of possible diversion and the impact it would have on the flows to India.”
Usually, to ensure that the flow downstream remains unaffected during the period of construction of a dam, the water is diverted through streams around the construction site and returned to the river.
“Since the flow of the water cannot be stopped, the water will be diverted so there will be no reduction of flow in this stage,” Mr. Iyer, who is an authority on dams and transboundary water issues, told The Hindu on Monday, speaking from New Delhi.
He stressed that he was speaking in general terms regarding any dam construction, and did not have specific details regarding how China was carrying out this particular project.
There is still some uncertainty on what China intends for the project, and whether or not a storage reservoir, which could affect downstream flows, will be built beyond the minimal “pondage” required to operate the turbines.
Chinese media reports indicated that the Zangmu project is unlikely to be the last on the Brahmaputra. A news report on the widely read portal Tencent said the Zangmu dam was “a landmark project” for Tibet's development, being the first major dam in Tibet, and “a project of priority in the Eleventh Five Year Plan.”
The report said that such projects would “greatly relieve the energy stress in the middle regions of Tibet” and upgrade power capacity from 100 MW to over 500 MW.

‘No treaty'

Mr. Iyer said a larger concern for India was the absence of a water-sharing treaty with China, which does not allow India to either qualify or address Chinese claims regarding specific projects.
“Between India and Pakistan, we have a treaty which specifies what we should do,” he said. “We're not supposed to retain a drop, and [even] during a stated period of construction, inflow is equal to outflow.”
“But with China,” he added, “we have no treaty. So what they will do, we have no idea.”