Explained: Why mountains in Himachal are rolling down

While cloudbursts and flash floods in recent years have become a regular feature in the hill state of Himachal Pradesh, the loss of life caused by natural calamities can be mainly attributed to the increasing human interference, particularly in eco-sensitive Himalayan zones.

Experts on Wednesday said that since mountains in Himachal Pradesh are part of Himalayan range that are young and fragile in nature, creating cracks and fractures in the rock could widen in future and create a rockfall or slope failure zone -- a phenomenon in which a slope collapses abruptly under the influence of rainfall or an earthquake.

They say anthropological intervention along with climate change have worsened it further. Be it development of hydropower projects or tunnels or roads.

Seven people died in the exceptionally high rainfall across the cold desert of Lahaul-Spiti district on July 27-28. Keylong and Udaipur subdivision of the district faced 12 incidents of flash flood after a cloudburst in which the Tozing Nallah impact was devastating, says a government report.

Two days before this disaster, nine people were killed by a landslide in Kinnaur district as boulders fell and hit the vehicle they were travelling in.

Both Lahaul-Spiti and Kinnaur fall in the Himalayan ranges, known for geological and ecological vulnerability.

This monsoon the heavy rains also caused major landslides in the state's Kangra district, claiming 10 lives. Terrifying videos capturing massive landslides in Sirmaur district are common these days.

Explaining why flooding and landslides are common in the hill states, Y.P. Sundriyal of the Department of Geology with Hemwati Nandan Bahuguna Garhwal University in Uttarakhand said, "Higher Himalayas, both climatically and tectonically, are highly sensitive, so much so, that at first stance the construction of mega hydro-projects should be avoided.

"Or else they should be of small capacity. Secondly, the construction of roads should be done with all scientific techniques. At present, we just see roads are being made or widened without taking proper measures such as no slope stability, lack of good quality retaining wall and rock bolting. All these measures can restrict the damage done by landslides up to some extent."

Citing a huge gap between planning and implementation, Sundriyal said for instance rainfall patterns are changing, temperatures have been increasing along with extreme weather events.

"There is no denying about the fact of development but hydropower plants, especially in higher Himalayas, should be of less capacity," he added.

Environmental activists claim the state's policy of promoting mega hydropower projects is being implemented in a fragile and eco-sensitive zone, without an appreciation of the cumulative impact of the works.

They say more than 140 hydropower projects have been allocated in the Sutlej basin and disasters like the ones in Chamoli and Kedarnath are in the making.

They demand a moratorium on the construction of all new hydropower projects located in the Sutlej and Chenab river basins until a study on the cumulative impact of the projects on the fragile ecology and livelihoods is done.

Saying urbanisation has led to decrease in soil infiltration capacity, resulting in floods, Central Water Commission Director (Flood Forecasting and Monitoring) Sharath Chandra said, "Himalayan systems are very young and fragile, making them unstable. The rain which was earlier recorded during the span of days now outpours within a handful of days only.

"This has led to an increase in incidence of flash flooding and landslides, making the region very vulnerable to natural disasters. If the landslide comes down to the river stream, it increases the chances of floods."

Experts say the higher Himalayas were once home to a lot of glaciers, which have now retreated owing to global warming and climate change.

Glacier is a moving mass of ice, soil and rocks and thus, it consists of lots of loose sediments.

According to geologists, the retreating glaciers have left behind unlimited sediments that consist of an unstable mix of earth and rocks in the higher reaches of Himalayas.

In such cases, even less rainfall is good enough to move the boulders and debris downstream. Hence, the higher Himalayan region is very unsuitable for dams and tunnels due to higher concentration of sediments.

Centre for Policy Research Senior Fellow Manju Menon said the social and environmental risks of large dams are well-documented.

Experts of Himalayan rivers have been warning about these risks for decades but unfortunately Environmental Impact Assessment (EIA) for these projects withhold or underlie this information so that projects get approved.

"Given all these projected risks, development and environmental policies should really not be selecting these options that put people at great risk. This is a moment for all our decision-makers in state governments, courts and Parliament to review their support for Himalayan dams," she added.

The hills of Himachal Pradesh, especially in Chamba, Kinnaur, Kullu, Mandi, Shimla, Sirmaur and Una districts, are prone to natural disasters like flash floods, cloudbursts and landslides.

Manshi Asher of environment research and action collective group Himdhara Collective told IANS that the local people have been speaking up against hydropower development for more than a decade now. And now the youth are also actively demanding a halt on these projects.

"It is high time the government listens to people's voices because the constitution grants tribals (of Lahaul-Spiti and Kinnaur) the right to say 'no' to any development that threatens their existence and survival," she said.

Prakash Bhandari of her group added, "Apart from being a geological and ecologically fragile region, Kinnaur is a strategically sensitive area. And most importantly this is a scheduled V area with a majority tribal population. It has a thriving apple economy which should be protected."