The last 125 km

Published: Tuesday 15 July 2008

Tapping energy or sapping the Himalayas?

Down to Earth
Chandi Prasad Bhatt
A series of dams are being planned on the Ganga between the Gangotri glacier and Uttarkashi to generate hydropower. The government has an economic agenda that requires huge amount energy. Well, it can go ahead, but only after it has satisfied me on seven counts.

There should be a detailed, in-depth study of the geology and the structures, by a team of scientists whose credential is proven and who should be inducted from reputed research organizations.

There should be an inventory of both active and old landslide deposits at the project sites. Sediments going to be flushed into rivers that are already sediment-laden must be estimated. This inventory will help assess the threat of inundation downstream.

For a long time now, I have been requesting a specific kind of study. The area the projects are coming up in has experienced two major earthquakes in the last decade. But, till today, except for some work related to an increase in landslides, it is still not known how these quakes changed the terrain.

Thus, there should be a study that give us an insight into the nature and distribution of fractures and fissures prior to the earthquakes, and after. This is essential we must avoid incidents like Bhenti and Varnawart, deadly landslides where entire villages were swept away.

Just to remind you, the area the projects are being planned in, called the main central thrust (mct) of the higher Himalaya, is known to be very sensitive in terms of landform stability. A majority of landslides, flash floods and termors occur in the vicinity of the mct. If one travels from river Kali to river Tons, one can see both active and stabilized landslides distributed on the southern slope of the mct zone. We are still grappling in the dark as to exactly when the fractures will lead to threshold perturbation.

We all know our engineers can make stable structures, using state-of-the-art technology. But how can they strengthen rocks that have been pulverized and are prone to small perturbation? Think of Chain village, near the Vishnuprayag project tunnel, which is showing signs of subsidence. Can engineers ensure the up-coming projects will not do the same to other villages?

Down to Earth
I am told that the fragile reservoir rim area around Tehri dam has already become unstable. As a result, much sediment is getting into the reservoir from the slopes. What if something similar happens in the new proposed projects?Water discharge data are simply too scanty. I request our planners to remember the frightening experience with the Vishnuprayag project, where planners failed to anticipate the decrease in water discharge during the winter. Considering that the new projects are located in the higher Himalaya, where water discharge is largely modulated by seasonality, this aspect should be takenseriously. More so, mounting evidence suggests that Himalaya glaciers are receding at an alarming rate. If that happens, the future of these projects is going to be seriously affected. Have we thought about this?

We must realise that in spite of the rugged terrain, people living in the region still depend on agriculture. With the rise inpopulation, individual landholding has significantly reduced over the years. In addition, expansion of urban areas, road building activity and hydroelectricity projects have further marginalized the individual landholding in Uttarakhand.

In the last few years, there has been a significant increase in the number of proposed hydroelectricity projects in various river basins. A majority of these projects are run-of-the-river schemes, implying no major submergence is involved. But as we know, a sizeable number of productive agricultural fields is located proximal to the river beds which are irrigated through traditional canal system. Many such productive fields will be submerged forever.

Have we estimated the consequences of depriving locals of their productive agricultural fields?

One more caveat. The impounding of water behind barrages is certainly going to change the micro-environment of the basin (at local scale). Down-stream, too, there will be reduced flow. We have no idea how these changes are going to affect the micro-biological and ecological environment. Do we know what we are doing to the Himalaya?

Chandi Prasad Bhatt is an eminent activist and environmentalist

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