The hill town of Joshimath, located in the Garwhal Himalayas in Uttarakhand, faces the risk of sinking. Residents of the town took out protests demanding action by the state government after cracks gradually developed in homes, roads and fields over the past 14 months.
Widespread panic ensued when a temple collapsed in Joshimath on January 6, alarming residents who have been living under constant fear amid heavily cracked walls of their houses for over a year.
After a team of experts conducted an on-the-spot inspection of the town, Chief Minister Pushkar Singh Dhami on Saturday ordered immediate evacuation of 600 families living in houses at risk.
But why is this town, nestled in between pilgrimage sites like Badrinath and Hemkund Sahib and serving as a pit stop to skiing destination Auli, and Valley of Flowers, at risk of sinking?
Experts have attributed the subsidence to mainly two things. Geological and man-made reasons.
Alarm bells by experts are however not recent. As early as 1976, the Mishra Committee in its report had written about the town's location on an old subsidence zone, corroborating with E Atkinson's words from 1886 that Joshimath was located on landslide debris.
The town was built over a century ago on landslide debris which has a low bearing capacity. The reason why settlements built on landslide debris are considered unstable is due to the loose structure of the upper layer of soil.
Loose soil cannot hold heavy construction especially when built in an unorganised manner.
As Joshimath is the gateway to tourist and pilgrimage destinations, haphazard construction activities have been going on in the area for a long time without thinking about the pressure the town is capable of coping with, Kalachand Sain, director of the Wadia Institute of Himalayan Geology said on Friday.
He added this may also have led to cracks appearing in the houses there.
‘Hotels and restaurants have mushroomed everywhere. The pressure of population and the size of the crowd of tourists has also increased manifold,’ Sain said.
‘Many houses in the town are unlikely to survive and people living in them must be shifted to safe locations as life is precious,’ he added.
According to experts, when construction work is done in high altitude places like the town of Joshimath, it obstructs the natural flow of water, adding to drainage woes.
When natural flow of water is obstructed, it finds different ways to come to the surface thus building pressure which the loose soil cannot bear.
However, Sain stated that the factors contributing to Joshimath's sinking are not recent. Rather, they have built up over a long period of time, he said.
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Apart from being developed on the debris of a landslide triggered by an earthquake, two other principal factors for subsidence are the town's location in seismic zone V which is more prone to earthquakes besides gradual weathering and water percolation which reduce the cohesive strength of the rocks over time, Sain told PTI.
Dr. Swapnamita Vaideswaran, Scientist, Wadia Institute of Himalayan Geology also revealed in a 2006 report that the drainage system of the town of Joshimath is not well maintained. Waste water from the days' usage flows through the improper drains.
Speaking to India Today, Dr. Swapnamita said, 'The nalas of Joshimath have been blocked by the sludge that came from the 2013 Himalayan tsunami and the Rishiganga flood disaster of 2021 worsened the situation. It was followed by incessant rainfall in the region between August to October 2021. The problem has been long spreading.'
Dr. Satyendra Mittal, professor of Civil Engineering Department at IIT Roorkee on Thursday told news agency ANI, 'There is under-construction activity in the affected area, the tunnel work is going on and its lining is not completed yet. So in this situation, water inside the tunnel, seeping out from any point of the tunnel is not surprising.'
He added, 'The water which is seeping out from some unknown place of the tunnel must be getting accumulated somewhere and when that water gets accumulated beyond the land's capacity, it increases hydrostatic pressure, whose aftermath is land subsidence.'
Rightly stressing measures to stop such disasters, Dr Mittal said, 'A team should be constituted for surveying the land, and identify the places from where water seepage is taking place.'
'And apart from this, the locals of Joshimath should be trained so that they be prepared for such situations. They should also be taught 'Architectural Art'. They should be given the knowledge of avoiding any work which can be fatal in future,' he added.
After the evacuation of people in affected areas to safety, microzonation of the town, replanning of its drainage system and rainwater outlets besides assessment of rock strength among others should be undertaken, Kalachand Sain suggested.
with PTI inputs
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