Why is the land sinking in Joshimath?

Last Updated13/01/2023

Cracks first appeared in a few houses in Uttarakhand’s Joshimath town in October 2021.
Over a year later, by January 11, 2023, 723 houses in all of the nine wards in the town had developed major or minor cracks on the floors, ceilings and walls.

Elevation: Situated at a height of 6,107 feet
State: In the Chamoli district of Uttarakhand
Population: ~ 23,000
Heavily built-on: Hotels, resorts, & a market for tourists, pilgrims, trekkers & personnel of the Army & Indo-Tibetan Border Police (ITBP).
Strategic importance: It leads to villages along the India-China border & en route to Barahoti, a disputed territory along the border.
Cultural significance: Gateway to Badrinath & Hemkund Sahib; & Valley of Flowers, a UNESCO World Heritage site.

Joshimath’s geological setting & unplanned construction: Cracks appeared around town and residents resorted to repairs.
Built on the deposits of an old landslide: It means that the slopes can be destabilised even by slight triggers.
Located in Seismic Zone V: It denotes the highest risk as it lies between two thrusts, the Main Central Thrust (MCT) and the Vaikrita Thrust (VT).
High slope mobility: Because of the MCT, the area around Joshimath is highly active in terms of slope mobility.
Extreme weather conditions: Climatologically, Joshimath lies in a region that frequently receives high-intensity, focussed rainfall which could trigger landslides.
Impact of floods of 2013 & 2021: It heightened erosion in the area that worsened the subsidence and vulnerability to landslides.
Lack of drainage and wastewater disposal systems: ~ 85% of buildings in the town aren’t connected to a sewerage system & have soak pits that could create “cavities between soil and boulders”.

About: It warned against heavy and unscientific construction in the town saying that Joshimath is a deposit of sand and stone.
Warning: Cautioined that vibrations produced by blasting and heavy traffic will also lead [to] disequilibrium in natural factors.

Blame by locals: They said that NTPC’s 520-MW Tapovan Vishnugad hydropower project, under construction in the area, exacerbated Joshimath’s land subsidence.
Background:
December, 2009: A tunnel boring machine punctured an aquifer ~ 5 km from Joshimath - released water at 700-800 litres per second.
After the incident: water sources in Joshimath started to dry up.
Continuing discharge of water: The amount of discharge has reduced over the years, it has still not stopped.
Denial of NTPC: No scientific studies establishing links between the puncture and the subsidence in Joshimath.

Helang-Marwari bypass: A 6 km highway being built by the Border Roads Organisation (BRO), is under scrutiny for destabilising the local topography.
Part of the 825-km Char Dham highway expansion project: Already being questioned for unscientific slope-cutting, leading to landslides.

This is image title