Himachal: Rains wash away ₹2,739 cr NH-22, geologists blame unscientific design

Three years of efforts of four-laning in the first phase of the national highway (NH-22) in Himachal Pradesh between Parwanoo to Solan towns have again virtually been washed away this monsoon—with less than 10% of the 39-km long, newly-laid road motorable in one stretch.

Motorists say the maximum damage to the road is on a 30-km stretch between Parwanoo and Kumarhatti, where over 20 km is either badly damaged or piled with boulders and muck due to frequent landslides.

They fear a threat to life from the falling debris while travelling through the hills that have been excavated for highway widening.

Even the executing agency, the National Highway Authority of India (NHAI), for the project—which aims to cut travel time between Chandigarh and the Himachal capital Shimla by shortening the distance by 17 km—does not know what to do with the falling boulders and muck.

It is simply putting the blame on heavy rains that are triggering landslides, damaging the road network time and again. Last year, too, this stretch was damaged by landslips during the monsoon and had to be rebuilt.

“We can't do much as the loose hill strata could hardly withstand the rains,” said Gursewak Singh Sangha, NHAI Regional Officer in Shimla.

He said that, in some stretches, NHAI had constructed retaining structures like breast walls up to the height of 12 metres but sliding rocks and boulders damaging them badly—as well as the highway.

“For the past two months we have not made much progress in the construction of the stretch between Parwanoo and Solan owing to rains,” he added.

The ₹748 crore outlay for four-laning the Parwanoo-Solan highway lapsed in March. A total of 23,785 trees faced the axe for its widening.

Geologists blame unscientific cutting of precipitous hills, largely of shell, sandstone and clay, for the frequent landslips.

"Most of these mountain slopes are of sedimentary formation and have become destabilised with the reckless cutting by heavy earth-moving machinery. The loose and naked boulders with muck will continue to roll down on the highway for eight to 10 years more," former state geologist Arun Sharma told IANS.

The highway construction lacks proper design and has been poorly executed... the debris could continue to fall till the angle of repose (slope stability) is maintained in the mountain cutting, he said.

The angle of repose is the angle of maximum slope at which a heap of any loose solid material will stand without sliding.

"On the Parwanoo to Solan stretch, most of the hill cutting was done largely vertically than horizontal. At some points, large-scale vertical cutting was carried out," Sharma said.

Vertical cutting was mainly done due to less land acquisition as horizontal cutting needs more land, added Sharma, a member of the Union Environment Ministry's State Expert Appraisal Committee to assess projects.

Driving uphill to Shimla or the Kasauli hills is not pleasureable for motorists these days, remarked Ramandeep Bains, a motorist from Chandigarh.

"In fact, it's a nightmare now. Almost every day one comes to know of incidents of landslips and falling rocks hitting moving vehicles," Bains told IANS.

Some of the stretches along the Parwanoo-Solan stretch have become permanent landslide points like Chakki ka Mor. The risk of driving is aggravated after dusk.

In the next phase, the four-laning of a 22-km-long stretch between Chambaghat and Kaithlighat is scheduled. It will cost around ₹598 crore. Then work will begin on the last stretch between Kaithlighat and Shimla.

Official sources said that the four-laning of the 89.71-km stretch that connects Shimla and Parwanoo—on the Haryana-Himachal border—would cost ₹2,739 crore as per initial estimates.