New Delhi, March 31: India has in principle approved two new dams on the Brahmaputra in Arunachal Pradesh as a buffer in case China siphons the river’s waters from Tibet to its parched northwest.

The plan is to build the twin dams on the river Siang — which is what the Brahmaputra is called in Arunachal Pradesh as it enters the state from Tibet — Union water resources ministry officials said.

The dams’ reservoirs are expected to store 10 billion cubic metres of water, collected from the Siang and smaller rivers in the area, which can be released into the Siang if China turns off the tap.

With Arunachal giving its nod to the project, after earlier raising submergence concerns, a detailed project report is expected in the next five years.

“The principal concern is strategic. In case Beijing diverts the river, then at least the Brahmaputra will not run dry,” a senior ministry official told The Telegraph.

Besides, the dams are expected to generate 10,000-12,000MW power. And in case Beijing does not divert the waters, the Siang project will at least reduce the threat of yearly floods in Assam.

For the past few years, there has been talk in the Chinese media about the ambitious diversion plan on the Tsangpo — which is what the Brahmaputra is called as it originates in Tibet and flows eastward towards Arunachal’s northeastern tip. Such diversion would come at a huge cost to Assam and Bangladesh, heavily dependent on the Brahmaputra’s waters.

The twin dams are being planned some 60km from the Chinese border, the sources said. The government gave the go-ahead for a feasibility study this month.

Arunachal had held up the plan for the past few years, mainly because it feared the project would submerge the town of Tuting in Upper Siang district. It also had environmental concerns.

Ministry officials said the project had now been “redesigned” to spare the inhabited areas — instead of a single dam generating over 12,000MW electricity, two smaller dams would be built. Delhi also plans to compensate Arunachal for any submergence.

But one huge “challenge” still remains, ministry officials concede -- the Siang flows though a highly seismic zone.

Delhi believes that Beijing is determined to go ahead with the diversion project. “Every time we ask them, the reply is in the negative. But you never know,” a senior official said.

The Chinese media has been making references to a huge budget allocation for a new road in Tibet, the Bomi-Medog highway, linking the lower Tsangpo valley with Tibet’s main east-west highway. The allocation is astounding considering Medog’s sparse population, and Indian officials suspect the road is meant to facilitate the Tsangpo diversion project.

Delhi also has in mind how China exploited the Mekong without regard to the other countries the river flows through, the officials said.