Landslides Hazards

Another form of the natural hazards in the state is the occurrences of landslides. The hills and mountains of Himachal Pradesh are liable to suffer landslides during monsoons and also in high intensity earthquakes. The vulnerability of the geologically young and not so stable steep slopes in various Himalayan ranges, has been increasing at a rapid rate in the recent decade due to inappropriate human activity like deforestation, road cutting, terracing and changes in agriculture crops requiring more intense watering etc.

Landslides are known to pay havoc causing death and destruction. In India, Western and Eastern Ghats, Jammu and Kashmir, Himachal Pradesh, Uttranchal and North Eastern Parts as well known for landslides. Delineation of landslide-prone areas requires a large data set. Various forms of landslides are slumps; debris or rock slides, debris falls or rock falls. Various factors influence the landslides: steepness of slopes, saturation by heavy rains or melting snow and ice, rocks vibrations, excess load from embankments, fills and waste dumps, changes in water content, frost effect, weathering of rocks, effect of ground water, and change in vegetal cover.

The hills and mountains of Himachal Pradesh are liable to suffer landslides during monsoons and also in high intensity earthquakes. The vulnerability of the geologically young and unstable steep slopes in various Himalayan ranges, has been swiftly increasing in recent decades due to inappropriate activity, such as deforestation, road cutting, terracing and changes in agriculture pattern requiring more intense watering.

The important slides in Himachal Pradesh which caused huge damage are:

• Maling (1968). This slide damaged 1 Km NH-22 and is still active.
• Kinnaur (Dec.1982) This occurred at Sholding nala collapsing 3 bridges and 1.5 of road was vanished.
• Jhakri (March 1989) At Nathpa about 500 m of road was damaged due to this slide and is still active.
• At Luggarbhati on 12 Sept.1995, 65 (39 as per official record) were buried alive during the slide.
• Prominent slides in Beas valley are at Marhi, Bhang, Chhyal, and Mandu in upper catchment of the Beas river.

The devastating landslides in H.P. need more intensive scientific studies and engineering measures focused on the problem of landslides. As per the first step, it will be necessary to prepare zoning maps of landslides and rock fall prone areas through geological and geo technical studies. The landslide prone areas should avoided while locating new settlement or buildings, and those, which are already occupied, should either be resettled or protective measures undertaken based on expert advice. The landslide proneness of the districts as compiled by the BMTPC is as under:

Landslide Prone Areas of Himachal Pradesh 
(Area in square kilometer)

Source: BMTPC, Landslide Hazard Zonation Atlas of India.

• Template for preparation of Detailed Project Report for site specific Landslide Risk Mitigation (Source: NIDM)
• Landslide Hazard Risk Assessment Report