Context:

• The deaths and destruction by landslides in Himachal Pradesh recently have led to much-needed attention on the Himalayan ecosystem.
• This article highlights the need for building resilience against geohazards caused by different causative factors like natural processes, environmental degradation and anthropogenic activities. 

Stresses in himalayan ecosystem

• Tectonic or neo-tectonic activities, associated with numerous subsurface processes like rock deformation and reworking of rocks and surface processes such as erosion, weathering and rain/snow precipitation make the ecosystem inherently fragile. 
• Climate-induced excessive events like freezing/thawing and heavy rain/snow precipitation lead to avalanches, landslides, debris flow, glacial lakes outburst floods, landslide lakes outburst floods and flash floods. 
• The Himalaya is further stressed by anthropogenic activities.

Reasons for increased vulnerability of mountainous ecosystem to landslides

• Climate change induced adversaries: Climate change has adverse impacts on glaciers, riverine systems, geomorphology and biodiversity, which, in turn, have increased the vulnerability of people in the mountainous states.
• Land degradation aggravates the existing vulnerability.
• Geographical factor: The confluence of the Westerly Disturbance and the South West Indian Summer Monsoon have caused excessive and concentrated rainfall in parts of J&K, HP and Uttarakhand leading to landslides and flash floods.
• Hilly regions are associated with slope instability and are prone to landslides. 
• Riverine flow, the cutting down of the toes of slopes and deforestation are some other factors that make a region vulnerable to landslides. 
• The convergence of the Indian plate with the Eurasian plate in the Himalayan region has  created subterranean stresses that get released in the form of earthquakes which, in turn, cause fractures and loosen the litho-structures near the mountain surface. This increases the possibilities of rock movement along the slope. 

How to overcome the stresses?

• Integrated early warning system: 
  • A network of relevant sensors, real-time monitoring, analysis and integration of data and the development of an integrated Early Warning System (EWS) based on AI/ML algorithms are measures that need to be adopted urgently.
  • Landslide warning systems should draw on an understanding of the rainfall threshold of a slope. 
  • Monitoring through web-based sensors like rain gauge, piezometer, inclinometer, extensometer, InSAR, total stations can help. 
• Vulnerability mapping: Various parameters like debris flow and underground water can be used to prepare vulnerability maps and the region can be categorized according to risk zones — most vulnerable, moderately vulnerable and least vulnerable.
• A Council of Himalayan States must be forged to gauge the impact of surface and subsurface stresses. 
  • It should try to simulate the hazard scenario caused by natural processes, environmental degradation or climate-induced phenomena, and anthropogenic activities in hill stations or towns. 
  • The disaster management authorities of the states should come together under the centralized council. 
  • Though the Himalaya is heterogeneous over its long stretch, the knowledge from different sets of assessments needs to be disseminated and shared by all Himalayan states.
• Environmentally sustainable socioeconomic development of the region is of paramount importance for which a balance must be ensured between the exploitation of resources and ecological sustainability. 
• Efficient town planning that accounts for the idiosyncrasies of the mountain is needed. For instance
  • Heavy constructions should be barred.
  • Care should be taken to have a proper drainage system.
  • Scientific slope cutting.
  • Emphasis should be on having retaining walls and adherence to building codes. 
  • High-resolution mapping of all towns and an assessment of their load-bearing capacity should be essential to the framing of building codes.