Prognosis and mitigation strategy for major landslide-prone areas Varunavat Parvat landslide in Uttarkashi

Introduction
Himalaya isolates the Indian subcontinent from the rest of Asia. This highest and
youngest mountain of the world was formed as a result of the coming together and
eventual collision of India and mainland Asia. The people of Himalaya have borne the
consequences of the quickened paces of the earth’s processes including the
ever-threatening natural hazards (Valdiya, 2001). Major part of the state of
Uttaranchal (now called as Uttarakhand) lies in the fragile mountain belt of
Himalaya and has experienced tectonic turmoil several times in the distant past.
During the last quarter of twentieth century there has been an increase in the frequency
of natural disasters in this region. Major disasters in the last few years include
Uttarkashi Earthquake of 1991, Chamoli Earthquake of 1999, infamous landslides of
Okhimath and Malpa in the year 1998 and cloudbursts and flash floods in Khetgaon
and Budakedar area during the monsoons of the year 2002. Sudden increase in
anthropogenic activities like unplanned cutting of slope, blasting of highly jointed rock
mass for road construction and unplanned disposal of the slope cut debris have further
added to the fragility of Himalayan mountains and consequently there has been an
increase in the vulnerability of this region to natural disasters (Uniyal and Prasad,
2006).
In the first decade of the twenty-first century no other landslide in Himalayan region
got more media attention than the landslide events from the hill called Varunavat
Parvat in Uttarkashi township of Uttarakhand. Uttarkashi township in situated on the
banks of Bhagirathi river (which is called Ganga in the downstream of Devprayag) at
an elevation of 1,152 mts and is the district headquarters for the northern hill district of
Uttarkashi named after this township (Figure 1). The township of Uttarkashi has a
population of about 16,218 (Census of India, 2001, 2004) and is located on
Rishikesh-Gangotri National Highway (NH-108) at a distance of about 200 km (approx.)
from Dehradun, the capital of Uttarakhand state of India. This township lies in the
fragile mountains of Himalaya and has a long history of natural disasters. Flash floods
of Bhagirathi river in the late 1970s, Gyansu landslide more than two decades back in
1980, earthquake of the year 1991 have caused wide spread damage to life and property
in Uttarkashi township and elsewhere in the district. The most recent disaster in this
township has been large-scale landsliding from the hill called Varunavat Parvat, since
Prognosis and
mitigation
strategy
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Figure 1.
Location map of study
area