Netting the slopes: Highway safety boosted as landslide risks reduced

In a bid to stabilise landslide-prone, excavated slopes along the Parwanoo–Waknaghat stretch of National Highway-5, the National Highways Authority of India (NHAI) has intensified slope protection measures using wire netting and other advanced techniques. These efforts have significantly reduced landslide incidents this monsoon, making travel safer for motorists on this four-laned highway.

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Historically, the 39-km Parwanoo–Solan and 22-km Chambaghat–Kairighat stretches have faced recurrent monsoon-triggered landslides since the hills were carved out for widening the highway. The situation turned particularly grim in July 2023, when heavy rainfall and cloudbursts wreaked havoc on the region. The state recorded 249.6 mm of rain from July 1 to 11—over three times the normal of 76.6 mm. This deluge led to flash floods, massive landslides, and the closure of key highway sections, including a 70-metre hill collapse at Chakki Mor near Parwanoo.

In total, 26 critical points—including Chakki Mor, Datiyar, the Barog bypass tunnel and Sanawara—faced severe damage, often disrupting vehicular traffic. A recent spell of heavy rain again caused temporary closure of parts of the highway, highlighting its ongoing vulnerability.

To mitigate future risks, the NHAI awarded the slope protection work to Jammu-based SRM Contractors Limited in 2023. Since then, engineering interventions such as wire netting and shotcrete have been deployed. Work has already been completed at several locations including Saproon and Rabon near Shamlech, while efforts continue at others like Dharampur and Waknaghat.

Anand Dahiya, Project Director, NHAI, Shimla, noted that engineering designs are being customised based on the unique geological conditions of each site. At Chakki Mor — one of the most erosion-prone areas — construction is set to begin soon after design vetting by Satluj Jal Vidyut Nigam, which has been engaged as a technical expert.

The highway was widened to four lanes in April 2021, but slope protection gained urgency only after repeated instances of slope failure. Initially, only minimal stabilisation (1.5–3 metres) was done, leaving vertical slopes of up to 30 metres highly susceptible to erosion from water seepage during the monsoon. The current protection drive, incorporating broader and technically advanced solutions, now offers renewed hope for long-term safety and road stability.