Preventing landslips

THE National Highways Authority of India (NHAI) has finally got down to the task of minimising landslides by initiating the process to stabilise the mountain slopes along the Parwanoo-Solan section of NH-5. Ever since the four-laning of the Chandigarh-Shimla highway began in 2015, this section has become more vulnerable to landslips. The lives of motorists are imperilled and several fatalities have been reported, too, as mounds of debris and boulders often come crashing down from excavated slopes during the rainy season. Notably, the construction of this Rs 748-crore stretch has been mired in controversy due to lapses in landslide-prevention measures. Doubts were raised over the design work when some retaining walls caved in during the monsoon in 2015. While the hills were vertically excavated by 15m to 30m, breast walls of only 1.5-3m height were raised. They proved to be too low to contain landslides as the exposed slopes gave way easily.

Even as need-based modifications were made, the NHAI must learn a lesson from this experience. Whenever it undertakes such jobs in the Himalayas, engineering technologies to prevent landslides must be utilised right from the outset rather than later. As per the National Remote Sensing Centre data released in February, the north-west Himalayas account for 66.5 per cent of the landslides in the country, followed by the north-east Himalayas (18.8 per cent) and the Western Ghats (14.7 per cent). Rudraprayag, Tehri Garhwal (Uttarakhand), Rajouri, Pulwama (J&K) and Thrissur (Kerala) are the top five hill districts most vulnerable to damage by landslips as they are not only landslide-prone but also have a high density of people, livestock, houses and roads exposed to these disasters.

With the hill states undergoing rapid concretisation, they should follow Aizawl’s landslide action plan. To ensure the slopes’ stability, it has made a geo-technician’s assessment mandatory for construction activity in the vulnerable zones.