From geology to unplanned construction:
Decipher why Josimart is going bankrupt
At 1890 meters above sea level, Joshimath is a Ghawal Himalayan town and an important stopover for both pilgrimage and trekking routes. But the city of over 20,000 people sits on a fragile hillside made even more vulnerable by unplanned and indiscriminate development.
This is the science behind the decline.
1. Location, Terrain, and Extreme Weather
Josimas is located on a hillside and is bounded by the Karmanasa and Daknara rivers to the west and east, and the Dhauliganga and Alaknanda rivers to the south and north. According to the Uttarakhand Disaster Management Department (USDMA) investigation, the city is located in a landslide-prone area and the Mishra Commission report in 1976 reported the first ground subsidence.
“The area surrounding the city of Josimart is covered by a thick layer of excess material. Large boulders of gneiss and fragments of bedrock and shale are embedded in a greyish, silty, sandy matrix. This makes the city highly vulnerable to collapse," said USDA Executive Director Piyoosh Rautela.
According to USDA research, perennial streams, heavy snow in the upper reaches, and heavily weathered and weakly cohesive gneisses make the area vulnerable to landslides. “The flood events of June 2013 and February 2021 will be driven by toe erosion and landslides along the Ravigram Nara and Naw Ganga Nara rivers, which have increased since the Rishiganga flood on February 7, 2021. It had a negative impact on the landslide zone,” said the study. This refers to the eruption of a glacial lake that caused flooding that killed 204 people, mostly migrants working on hydroelectric projects.
The landslide zone further weakened when Joshimath recorded 190 mm of precipitation in his 24 hours on October 17, 2021.
The effects of extreme precipitation events can be seen in the latest satellite data. This indicates that the mountain stream has widened its channel and changed course, causing slope instability in an already vulnerable belt. The enormous amount of debris-laden water that has been carried in has exacerbated toe erosion along the left bank of the lower Alaknanda River, which joins the Dhauliganga River at Vishnu Prayag. This has adversely affected the stability of the slopes on which the city of Josimart is located," the USDA report said.
2. Geology
The study also showed that ecostructural and geomorphological factors combined with meteorological features make the Jocimat region highly susceptible to subsidence. Joshimath is in the Chamoli district, which is within zone V of the seismic zoning map, and on the Richter scale he has witnessed multiple earthquakes below 5.
Joshimath is located almost at the summit of He Vaikrita Thurst (VT), a tectonic fault line. The city is also very close to the main geological fault lines, Main Central Thrust (MCT) and Pandukeshwar Thrust (PT). The MCT passes under Helan just south of Joshimas Town and borders the rocks of the Garhwal Group (Joshimas Formation), placing the town within the sphere of tectonic activity of the MCT.
A scientist at the Dehradun Geological Institute, who spoke on condition of anonymity, said, "Josimart is located near one and two fault lines and is highly vulnerable to subsidence due to tectonic activity."
In Helang, the Border Road Organization (BRO) is building the Helang Bypass, which uses heavy machinery to reduce the distance to Badrinath Temple by about 30 kilometres. Experts said this could lead to more landslides under "earth tectonic activity." His 1976 report on the Mishra Commission (headed by his MC Mishra, who was then a senior bureaucrat in Uttar Pradesh) recommended a ban on heavy industry in the Joshimath area. 3. Unplanned construction
Hemant Dhyani, an environmentalist and member of the High Power Commission (HPC) appointed by the Supreme Court for the Char Dham project, is well aware of the geological vulnerability of the area. said hydropower plants have been approved around Joshimath and Tapovan, including Vishnugad. HE project.
“The project headrace tunnel traverses the entire geologically vulnerable area beneath Josimart. A Tunnel Boring Machine (TBM) was used to excavate the tunnel. December 24, 2009 , broke through the aquifer about 3 km inward from the left bank of Alaknanda near Shelong village. More than a decade ago, experts warned that this sudden and widespread drainage of the formation could cause subsidence in the area. It's not surprising that the city is sinking because no corrective action was taken," he explained.
According to locals, several new skyscrapers were built in and around the town of Josimath during this decade. One such building recently collapsed due to ground subsidence. Kailash Joshwal, a Joshimath resident, blamed the state-owned Thermal Power Corporation's construction of a hydropower project for exacerbating the situation, with water from power tunnels seeping into homes and widening cracks. “In the landslide hazard zone, the construction of retaining walls has spawned many new buildings. I was.
According to his USDA research report in August 2022, unplanned development activities that do not fully consider soil bearing capacity are exacerbating problems related to slope instability at Josimas.
4. Poor drainage
An expert and his USDA pointed out why water infiltration from the surface has increased. First, human activity on the surface has disrupted natural drainage systems, forcing water to find new drainage channels. Second, the city of Josimat does not have a sewage and sanitation system. “Infiltration reduces the shear strength of the top layer soil,” Dhyani said. This can be seen around the village of Sunil in Josimaat, where the effects of land subsidence can be seen on bent water pipes.
