As heavy rains wreaked havoc in Himachal Pradesh, with dozens of deaths reported due to rain-induced landslides, experts on Thursday said that unscientific constructions in the ecologically fragile Himalayas, depleting forest cover, and structures near streams blocking the flow of water are causing frequent landslides in the region.
The surge in landslides is primarily attributed to extensive hill slope cutting for construction and road widening, tunnel blasting and hydro projects, according to geological expert Prof Virender Singh Dhar.
Himachal has observed vertical mountain cutting for road construction, often featuring retaining walls as small as 5 to 10 feet, he observed.
As per experts, the slopes in Himachal Pradesh have grown increasingly susceptible to landslides due to rock cutting at the foothills, inadequate drainage systems and exacerbated by intense rainfall, which collectively worsens the situation for the state.
Scientist Suresh Attre, specialising in climate change, has said the intensified rainfall, accompanied by elevated temperatures, has contributed to a heightened risk of landslides. This is particularly notable in areas where cutting has taken place downstream on the foothills, causing the strata to loosen.
Rainfall and Landslides in Himachal
On average, Himachal Pradesh receives around 730 mm of rainfall during the entire monsoon season spanning from June to September. However, this year, the state has already received 742 mm of rainfall, as reported by the Meteorological Department.
During the 55 days since the monsoon’s commencement, Himachal has encountered 113 landslides, according to the state’s emergency operation center. Notably, the Public Works Department (PWD) incurred a loss of Rs 2,491 crore, while the National Highways Authority of India (NHAI) suffered losses totaling about 1,000 crore, officials said.
Six-fold Increase in Landslides in 2022
Data compiled by the disaster management department reveals a concerning six-fold increase in major landslides in 2022. This year, there have been 117 significant landslides, marking a notable rise from the 16 incidents recorded in 2020.
17,120 Landslide-prone Sites
The state has identified a total of 17,120 sites prone to landslides, with 675 of them located near critical infrastructure and habitations, as per available data. Chamba holds the highest count of prioritised sites at 133, followed by Mandi with 110, Kangra with 102, Lahaul and Spiti at 91 and Una with 63. Additionally, Kullu stands at 55, Shimla at 50, Solan at 44, Bilaspur at 37, Sirmaur at 21 and Kinnaur at 15.
Noteworthy active landslide and sinking sites span across various regions are: Jhandota and Kakroti villages, Sapdoth Panchayat in Chamba; McLeodganj Hill and Bariara village in Kangra; Baridhar to Kalyan Ghati Road; Mansar near Salogra; Jabalpatwar village in Solan; and Kotrupi, Doada Hanogi, Mile 5, 6, and 7 near Pandoh, along with Nagani village in Mandi district.
Furthermore, notable locations encompass Urni Dhank, Batsari, Nesang, and Purbani Julha in Kinnaur, along with Nigulsari—site of a major landslide disaster on August 11, 2021, resulting in 28 deaths and 13 injuries.
Shimla district highlights ten marked sites: Krishna Nagar, Halog, Bangla colony, Totu, Baldiyan, Mehali-Malyana road, Nerva Rest House, Patti Dhank, Niyani, Dharali, Kool Khad, Browni khad, Ladanala, Kotighat, Jiskon, and Rohru-Chirgaon-OdtaKwar road.
Based on the Landslide Atlas of India by the National Remote Sensing Centre, ISRO, Hyderabad, all twelve districts of Himachal Pradesh are susceptible to landslides.
The Landslide Exposure Analysis covers 147 districts across 17 states, ranking Mandi district of Himachal at 16th place, followed by Hamirpur (25), Bilaspur (30), Chamba (32), Solan (37), Kinnaur (46), Kullu (57), Shimla (61), Kangra (62), Una (70), Sirmaur (88), and Lahaul and Spiti (126) in the socio-economic parameter risk exposure map.
Landslide-Affected Regions This Monsoon
Abdul Basit, NHAI Regional Officer in Himachal Pradesh, revealed that the recent heavy rainfall had left the mountains saturated, triggering cloudbursts and landslides that inflicted substantial damage to the road infrastructure.
Notably impacted are key stretches like Shimla-Kalka, Shimla-Matour, Manali-Chandigarh and Mandi-Pathankot.
Basit said instances of road cave-ins and landslides have been reported even in areas without any rock cutting activities. He said that the implementation of tunnels stands as the sole viable solution for ensuring continuous and unimpeded connectivity.
For addressing these challenges, a comprehensive plan has been set in motion. Sixty-eight tunnels have been proposed for Himachal Pradesh, with 11 already constructed, 27 currently under construction and 30 at various stages of preparation for detailed project reports.
(With inputs from PTI)