Context

The Char Dham project, inaugurated in 2016, aims to widen roads in India’s Himalayan state of Uttarakhand. However, the study of rocks in a key area where blasting is underway shows that the project is responsible for many of the landslides have been occurring recently.

About

• The project is one of the largest road-widening projects in the Himalayan region of India.
• The project aims to widen the roads to four of Hinduism’s holiest shrines in the Himalayas:
  • Kedarnath
  • Badrinath
  • Gangotri
  • Yamunotri

Which area is in question?

• The area in question is Tota Ghati (‘Parakeet Valley’), a less-than-10 kilometre stretch.
• It lies between Kodiyala and Sakhni Dhar on National Highway 58 in Tehri district, Uttarakhand.
• In this stretch, the highway passes through a complex geological terrain, with multiple rock types and slopes susceptible to ‘failures.’
  • A slope failure is a phenomenon in which a slope collapses abruptly due to weakened self-retainability of the earth under the influence of a rainfall or an earthquake.
• Tota Ghati, where there are seemingly stable rock slopes, has been in the news of late for having had a number of slope failures recently.
• The narrow stretch of Tota Ghati is dominated by limestone and interbedded shale rocks, shattered light grey dolomite, with occasional pockets (as fracture filling) of gypsum and purple grey shale and limestone.
  • This is called a ‘Karol formation’ in geological terms.
• The calcareous (calcium containing) rocks are highly jointed (two to three sets of intersecting joints), fractured and sheared due to three ‘thrusts’ passing proximally to Bayasi, Shaknidhar, and Teen Dhara.
• Field investigations reveal that Tota Ghati’s rocks are widely sheared, faulted and fractured.
• Often, the competent (strong) rock types such as quartzite also occur as shear bands and completely crushed rocks in the stretch.