Mega dams have always been a controversial issue. While their construction has been advocated as a non-polluting source of power generation and for flood control and irrigation, critiques have opposed them on three counts: environmental degradation, displacement of thousands from the villages that will be submerged and aggravating flood havoc downstream when due to heavy rains huge quantities of water have to be released to save the dams from being breached.

One major controversy relates to the Narmada River Valley Project which will displace 1.5 million people. A movement has been going on against it since the mid-1980s. Some environmentalists have called it “India's greatest planned environmental disaster.”

The dams - some proposed and some under construction - that have caused widespread resentment in the North-East are the Lower Subansiri, Lower Siang (both in Arunachal), Tipaimukh, Tuivai, Tuiral, Tuivawl and Serlui 'B' - all in Mizoram. The 2000 MW Lower Subansiri project is scheduled to be commissioned in 2012, while the 2700 MW Lower Siang project may be completed by 2017. Comparatively small are the ones in Mizoram - Tipaimukh (1500 MW), Tuivai (210 MW), Turial (60 MW) Tuivawl (40 MW) and Serlui 'B' (12 MW).

India seems keen on speeding up the Lower Siang project primarily for countering the Chinese who are building a number of hydel projects in Tibet. The Siang basin has an estimated hydel potential of 20,000 MW. The three projects that have been identified in the first phase, together have a capacity for generating 11,000 MW.

Assam has been firmly opposed to building big dams in Arunachal, especially the Lower Siang and Lower Subansiri projects for the adverse environmental impact they are likely to cause. Chief Minister Tarun Gogoi has given his firm “No” to construction of mega dams and claimed that Prime Minister Manmohan Singh was also not in favour of big dams. The new Governor of Assam, Shiv Charan Mathur, is also opposed to the construction of big dams in the North-East.

Last month Aizawl witnessed a massive procession of the Hmars who live in north Mizoram, protesting against building of hydel projects in areas inhabited by them. They fear large-scale eviction and loss of their traditional livelihood. In Assam, The Krishak Mukti Sangram Samity has been leading a movement against big dams. The Assam Gana Parishad (AGP) has threatened to launch a mass movement against building of dams in Arunachal and so has the powerful students body, the All Assam Students Union (AASU).

In Arunachal Pradesh, organizations of different tribes have expressed their fear not only about the environmental impact of big dams but also on account of the entire zone being tectonically unstable. A major earthquake, they fear, may cause disasters by breaking the dams. The All Arunachal Pradesh Students' Union (AAPSU) is also opposed, but for a different reason. More such projects will mean the influx of more “outsiders” who will eventually marginalize the local populace. This is their fear.

In the midst of this ballyhoo, Union Environment Minister Jairam Ramesh flew in to Guwahati last month and had a day-long heated “interaction” with eminent citizens and leaders of mass organizations. He tried to allay their fears on this account but did not seem to have succeeded. However, before leaving, he promised he would apprise the Prime Minister of the apprehensions of the people of Assam on the dam issue.

Meanwhile, the Arunachal Pradesh Government seems determined to go ahead with the hydro projects. It has signed ten MoUs for mega schemes which are expected to generate 30,000 MW of power in ten years' time. The State certainly does not need even a fraction of this power, nor does the industrially backward north-east. So the bulk of the power generated will have to be delivered to the national power grid for consumption by other States. But what will be the social and environmental cost? Most of the environmental damage will be irreversible and their full impact can be assessed only over a long period of time.

India is rightly apprehensive about the likely impact on the Brahmaputra of the dams that the Chinese are reportedly building in Tibet. If so much of the river's water is drawn and stored in dams upstream, so goes the argument, the waterflow and current velocity in the Brahmaputra will be reduced, increasing siltation and consequently causing more floods in Assam. (IPA Service)