Multiple early studies in Joshimath, underline rapid land subsidence, or sinking of land, in recent weeks in the town of Uttarakhand.
One preliminary estimate notes that areas where there is a high population, including tourists, witness high extraction of groundwater and high seepage of waste water into the ground which in turn aggravates sinking of land.
There are other areas in Uttarakhand as well as in the neighbouring state of Himachal Pradesh that face the risk of land subsidence and associated impacts on houses.
About four months ago, in September 2022, a state government report confirmed that Joshimath, a town in Uttarakhand, situated at an altitude of 1,875 metres, is sinking.
Last week, a preliminary report by the Indian Space Research Organisation (ISRO)’s National Remote Sensing Centre (NRSC) showed satellite pictures confirming a rapid subsidence event in early January in Joshimath.
Experts that Mongabay-India spoke to, following the rapid subsidence situation in Joshimath, have linked the land subsidence – or the sinking of land – to the most recent case of cracks developing in houses. As of January 17, 849 houses had developed cracks and 838 people had been evacuated.
According to the NRSC satellite-based preliminary study, which is now no longer in the public domain, Joshimath, the gateway to many famous pilgrimage sites, including Auli, Badrinath, and Hemkund Sahib, sank 5.4 cm in just 12 days.
The report noted that between April and November 2022, Joshimath sank by 8.9 cm. But a rapid subsidence event occurred between December 27, 2022, and January 8, 2023, during which the land subsided by 5.4 cm and over a larger area as well.
This report, however, has been removed from the ISRO site after getting instruction from the National Disaster Management Authority (NDMA), which restricted government organisations from interacting with media, claiming it is “creating confusion”.
Experts that Mongabay-India spoke to, however, feel that the free flow of information and knowledge-sharing is important at this time.
While there has been awareness, discussion and government committee recommendations about land subsidence in Joshimath for decades, a renewed set of complaints came in 2022 from residents, following which the Uttarakhand State Disaster Management Authority commissioned a study.
A multi-institutional team, comprising experts from IIT Roorkee, Geological Survey of India (GSI), Central Research Building Research Institute (CBRI) Roorkee, Wadia Institute of Himalayan Geology, and Uttarakhand State Disaster Management Authority (USDMA), arrived in Joshimath in August 2022 to study the causes of ongoing subsidence and suggest remedial measures.
In its report, submitted in September 2022 following a four-day survey, the team noted that there is evidence of ground subsidence happening in Joshimath and surrounding areas.
It highlighted that the town in Chamoli district lies on an unstable foundation – a fact that is well-documented, with one of the earliest records being from 1886 when Edwin T. Atkinson wrote about landslide debris where the town is based in the Himalayan Gazetteer.
Referring to the land subsidence in Joshimath, the USDMA report notes, “Joshimath and surrounding areas are known to experience ground subsidence since the Mishra Committee Report of 1976. After almost 50 years, there exists no data, record or report that could help in analysing and studying the state of affairs scientifically in a sequential manner; either with regard to the ground subsidence or measures put in place in accordance with the recommendations of the Mishra Committee and others that were constituted afterwards.”
Protests Blame Hydro Project
As cracks in Joshimath homes widen and residents are displaced, protests have started emerging.
Many parts of Joshimath are witnessing protests from people who put up banners against NTPC, the public sector energy conglomerate building large hydro projects near the town.
Experts, residents, activists and others attribute the ongoing situation of cracking homes, triggered by rapid subsidence, in Joshimath, to the NTPC Tapovan Vishnugad Hydro Electric Project (HEP) and the Char Dham national highway project.
However, NTPC has dismissed its role in the situation.
According to a media report, NTPC noted that the Tapovan Vishnugad hydroelectric project is 1.1 kilometres from the town and 1.1 kilometres below the ground – by which it means that the projects are at sufficient distance and not in a position to accelerate land subsidence.
NTPC has submitted this information to the union Ministry of Power, which sought NTPC’s explanation regarding its role in the subsidence of the town.
S.P. Sati, a professor of geology at the College of Forestry in Tehri Garhwal, says there is a need for a proper study to understand the impact of these projects on Joshimath.
The water from the Dhauliganga at Tapovan, where the tunnel for the Tapovan-Vishnugad project begins, should be compared to a sample of water leaking at Marwadi of Joshimath. It will give a sense whether the power project has any connection with the land subsidence, he added.
Joshimath Situated on Old Landslide Debris
Y.P. Sundriyal, a professor and head of the geology department at the HNB Garhwal University, recently wrote a discussion paper on the precarious situation of Joshimath and Bhatwari, two Himalayan towns in Uttarakhand.
The paper, written along with researchers from Doon University, Uttarakhand, Oslo Metropolitan University, Norway and National Geotechnical Facility, Uttarakhand is a pre-print and currently under review for the journal Natural Hazards and Earth System Science.
The pre-print attempts to estimate the possible displacement of land (sinking) in the future, in different scenarios and notes that based on factors such as gravity, rainfall, building load, domestic discharge, and seismic load, “the displacement in these hillslopes (sinking of land) might reach up to 20-25 metres that will further aggravate the situation” of subsidence in these disaster-prone towns.
The paper notes that the town is situated along a narrow gorge at the confluence of two major rivers; Dhauliganga and Alaknanda and is close to the Main Central Thrust (MCT) fault passing through on the southern side of town.
So, it is prone to earthquake and also frequent rainfall.
Sundriyal explains that Joshimath is located on the debris of an old landslide and there are fine materials like clay, soil, etc. between the boulders.
Highlighting the role of seeping water (natural and anthropogenic drainage) in the current situation in Joshimath, he said that when the drainage water seeps through the surface and goes underground, it loosens the material that is locked between boulders, which in turn shifts the boulders.
Another researcher, Vipin Kumar from the Department of Geology, Doon University, who was part of this study, says that Joshimath town is situated on an active paleo landslide which means the landslide debris, including soil, boulders, and other materials, continue shifting.
However, it is likely that the displacement (of slope materials) might have increased in the last three to four months.
Kumar notes that the high number of tourists that visit Joshimath leads to high extraction of groundwater and also discharge of liquid waste which seeps into the ground and affects the already-weak natural regime.
He added that their study found that those areas, where there are a high number of people and discharge of liquid waste, will get the most displacement in the form of hilltop material sliding down.
Similar Situation Arising in Neighbouring Areas
There are many villages across the state where cracks have been developing in the houses over the last several years. Other than Joshimath, Dar, a village of the Darma valley in Uttarakhand’s Dharchula sub-division has witnessed cracks in houses.
Experts say that about 200 villages of the Dharchula and Munsyari sub-divisions are developed on paleo landslides and are prone to subsidence.
Syana Chatti in Yamuna Valley, Kharsali Janki Chatti, Bhatwari in Bhagarithi valley, a few villages in Bhilanghana Ghati are some of the other areas where houses are witnessing cracks currently, says Kumar.
From Jaggi Bhagwan area in Mandakini valley people are already leaving their homes, Joshimath and Karnprayag are already in the news, there are many villages in Kaali valley as well, he said adding that there is no official record of habitations where cracks are witnessed.
There is a list of 395 villages that the Uttarakhand state government has identified between 2018 to 2021 as prone to disasters and that need to be relocated immediately.
According to S.P. Sati, there are many other towns across the Himalayas, especially in Uttarakhand – such as Gopeshwar, Pauri, the upper part of Srinagar, Guptakashi, a part of Augustmuni, Munsiyari, and a big portion of Nainital – where unplanned growth is happening, and they may face a similar fate in the coming future.
It is almost impossible to save Joshimath but we should learn a lesson from here and use it to protect other towns and cities, he added.
Like Uttarakhand, its neighbouring state Himachal Pradesh is also facing a similar situation of land subsidence.
On January 16, while speaking at the 148th Foundation Day of the India Meteorological Department (IMD), the chief minister of Himachal Pradesh, Sukhvinder Singh Sukhu, said that many places in the state are gradually experiencing land subsidence and urged the centre to take timely measures to avoid the Joshimath-like situation.
(This article was originally published at Mongabay. It has been republished here with permission.)
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