Vertical hill cutting, lack of paved shoulders to blame for damage to Parwanoo-Solan road

Ambika Sharma

Solan, September 4

The 39-km Parwanoo-Solan stretch of the Chandigarh-Shimla National Highway-5 had suffered extensive damage due to continuous heavy rain and landslides in the recent past. The damage was caused mainly because the hills were vertically cut for the construction and expansion of the highway due to limited availability of land.

The damage to the highway was aggravated in the absence of paved shoulders, which would have made water move away from the road before infiltrating into its base. Paved shoulders increase the life expectancy of the road surface.

At least five to seven stretches at Chakki Mod, Datiyar, near Dharampur, Sanwara, etc., were extensively damaged owing to large-scale erosion of excavated hill slopes due to heavy rain. Mounds of debris, boulders and fallen trees had continuously flowed down from the exposed slopes after every fresh spell of rainfall.

The right of way on the Parwanoo-Solan section of the highway was merely 28 m to 32 m. The work to expand the highway to four lanes was completed in April 2021. Experts say that the right of way should have been about 45 m to 50 m, giving more space for the creation of steps along the hills and avoiding vertical hill cutting up to 40 m. The maximum damage to the highway was caused due to the erosion of the exposed hill slopes that were left unprotected after being vertically cut.

Learning from its mistake, the NHAI has increased the right of way from 45 m to 50 m on the subsequent Solan-Kaithlighat stretch of the highway. This road stretch has paved shoulders, which have further provided stability to the highway, and has witnessed fewer landslides this monsoon season.

Regional Officer, NHAI, Abdul Basit says, “The Parwanoo-Solan stretch of the national highway-5 was the first project of the NHAI in the Himalayas where no pave shoulders were constructed. We are making improvements in the subsequent stretches of the highway.”