Observation pillars were erected on the identified vulnerable slopes around the Naini lake after devastating Sher-ka-Danda landslide of 1880 and these were monitored using theodolite till 1997 to assess the threat posed to the lake city and undertake mitigation measures, besides sounding a warning when required.
Monitoring unstable slopes
But then Joshimath in Chamoli district of Uttarakhand is known to experience ground subsidence since Mishra Committee Report of 1976. No institution around has however bothered to monitor the slope movement and so after almost 50 years, there exists no data or record to analyse the state of affairs scientifically and sequentially – either to identify risk prone areas or correlate the rate of subsidence with precipitation or toe erosion.
If not anything else, it is the recommendation to undertake regular monitoring of the slopes around Joshimath, for which the multi-institutional committee of officials from IIT, CBRI, WIHG and GSI constituted recently by Uttarakhand SDMA needs to be appreciated. Really speaking, mitigation works have to be planned and prioritized on the basis of differential risk assessed by monitoring.
Slope instability – A popular knowledge
Apart from this, most assertions of the committee are well known to one and all.
Everyone around knows and is aware of subsidence around Joshimath and structures witnessing cracks and fissures. These are no doubt commonplace around Ravigram, Sunil, Sema and Marwari as put forth by the committee, but people clearly perceive that other areas are really not safe and stable.
As regards the role of water, the committee has clearly quoted masses being aware of the role of toe erosion by Alaknanda river and enhanced pace of slope instability after floods in the river in 2013 and 2021.
The masses are also aware of the role of overloading the fragile slopes by heavy structures.
Though no scientific institution or committee has so far mustered the courage to comment on the role of tunnelling through the slopes that are long known to be unstable, masses are amply out vocal on this controversial issue as well.
As regards the observations of the committee – there being no in situ outcrops around middle and upper slopes and slope material being studded with bounders; it is not hard to deduce that the town is located over thick pile of old slide material.
The attitude of the rocks on the opposite bank of Alaknanda river all the more makes it amply clear that the slope material is poised for instability that can be exacerbated by anthropogenic activities; be these construction or tunnelling.
With no factual data available, the committee has deduced the areas around Ravigram, Sunil, Sema and Marwari to be more vulnerable only on the basis of visual impact on the structures.
As regards the recommendations, committee has nothing new to offer.
Reducing stagnation of water and facilitating speedy runoff have been known measures of landslide mitigation utilised traditionally by the people of the region – unbunded far flung agricultural fields and jungle guls.
These have at the same time been the main recommendations of the Ramsay Committee of 1880, as also several others formulated from time to time.
As such the committee has not much in concrete to offer. Slope monitoring and planning for water disposal should however be taken up immediately to realistically quantify and assess the seriousness of the problem and to retard the pace of ground subsidence.
Regulating construction could well be perceived a good suggestion, but it is hard to be implemented. Same is the case with evacuating people from identified vulnerable areas.
With economic activities concentrated around Joshimath and Auli, people are left with no choice but to take risk. If you don’t like calling this risk informed decision making you can call it a gamble.
Making public the slope monitoring data could however help people be more judicious, and it is ultimately voluntary action that is to make the difference.