GS Paper 1
Syllabus: Important Geophysical Phenomena/Disaster Management
Source: HT
Direction: The article examines the causes of the recent incidents of land subsidence in Joshimath, as well as the preventive measures that are required.
Context:
- The Uttarakhand government has banned construction work in and around Joshimath due to land subsidence, which has resulted in cracks in over 560 homes, prompting panicked locals to protest.
- Joshimath is the starting point for many Himalayan Mountain climbing expeditions, pilgrimage sites such as Badrinath and Hemkund Sahib
- It is the location of one of Adi Shankara’s four cardinal monasteries.
Science behind the subsidence:
Location, topography:
- Also known as Jyotirmath, it is a town (of over 20,000 population) in the Garhwal Himalayas in Chamoli District in Uttarakhand, located on the NH-7 (Rishikesh-Badrinath) at an altitude of 1890
- It is situated in the middle slopes of a hill bounded by the Karmanasa and Dhaknala streams on the west and the east and the Dhauliganga and Alaknanda rivers on the south and the north.
- According to the Mishra Commission report (1976), the first instance of subsidence in Joshimath was reported way back in 1976 and the town is –
- Located on the site of ancient landslides
- Covered with thick layer of overburden material
- The town area is prone to landslides and highly vulnerable to sinking due to scattered and highly weathered gneissic rocks with a low bearing capacity and loose soil due to seepage from streams uphill.
Extreme weather events:
- Flood events of June 2013 and February 2021 (flooding of Rishi Ganga) had adverse impact on the landslide zone as a result of extreme erosion.
- According to the latest satellite data, mountain streams have expanded their channels and changed course, thereby inducing more slope instability in an already fragile belt.
Geology:
- According to the Uttarakhand State Disaster Management Authority (USDMA), Joshimath falls in Zone V of the Seismic Zonation Map and has witnessed several earthquakes of magnitude of less than 5 on the Richter scale.
- Joshimath being on a fault line makes it highly vulnerable to sinking because of tectonic activity.
Unplanned construction:
- The Border Roads Organisation (BRO) is building the Helang bypass that will reduce the distance to Badrinath shrine by about 30 km, using heavy machinery.
- Hydroelectric (HE) schemes have been sanctioned around Joshimath and Tapovan, including the Vishnugad HE Project and a tunnel boring machine (TBM) was employed for excavating the tunnel for the project.
- In 2009, it punctured a water-bearing strata and experts had warned that this sudden and large-scale dewatering of the strata had the potential of initiating ground subsidence in the region.
Improper water drainage: According to the USDMA, this could be the reason for increase in ground seepage of water from the surface, which is a probable cause for subsidence.
Preventive measures:
| Immediate | Long-term |
| ● Relocating residents to a safer place.
● Experts recommend that all development and hydroelectric projects in the region be halted completely. |
● The town’s planning must be reimagined to accommodate the new variables and changing geographical factors.
● One of the most important factors that needs to be studied and redeveloped is drainage and sewer planning. ● Experts have also suggested replanting in the region, particularly in vulnerable areas, to retain soil capacity. |
Conclusion: To save Joshimath, the government and civil bodies must work together, with the assistance of military organisations such as the Border Roads Organisation (BRO).
Insta Links:
Mains Links:
Q escribe the various causes and the effects of landslides. Mention the important components of the National Landslide Risk Management Strategy. (UPSC 2021)
