KATHMANDU, July 24: The Department of Roads (DoR) has begun surveying an alternative route along the Trishuli River as a parallel to the Narayanghat–Muglin Road, a section frequently disrupted by landslides during the monsoon. The Department said route surveying and alignment work for the proposed road are currently underway.
DoR Director Dr Bijaya Jaishi said preliminary route alignment work has already started.
"At the local level, track opening has begun at several locations for the proposed parallel road. The concerned road divisions are also carrying out preliminary work," Jaishi said. "Construction will formally begin once the route alignment and track-opening work are completed."
The 35-kilometre Narayanghat–Muglin Road section, stretching from Pokhara Bus Park in Narayanghat to Muglin, has long been prone to landslides due to its fragile geology. Despite a major upgrade completed in 2018 at a cost of more than Rs 2 billion with financial support from the World Bank, the highway continues to suffer frequent disruptions every monsoon.
The road expansion project, launched in January 2016 and completed in August 2018, widened the carriageway from 5.5 metres to between 9 and 11 metres.
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According to Narayan Lamichhane, chief of the Road Division Office in Chitwan, landslides frequently occur at Tuin Khola, Jalbire, Setidobhan and several other locations along the highway.
"The Road Division Office has launched a Rs 220 million project to permanently stabilize the landslide-prone area at Tuin Khola," he said.
Lamichhane said road blockages are usually cleared within one to two hours.
Jaishi said the highway passes through geologically fragile terrain, while unplanned construction and road excavation above the highway by local authorities have further increased the risk of landslides, even during light rainfall.
Engineering flaws blamed
Geotechnical experts say insufficient attention was paid to geological conditions and engineering design during the construction and upgrading of the Narayanghat–Muglin Road, leaving it highly vulnerable to landslides and earthquakes.
A geotechnical expert and former additional secretary at the Ministry of Physical Infrastructure and Transport said the BP Highway underwent extensive geological studies and slope stabilization measures during construction, reducing the risk of landslides.
"However, similar attention does not appear to have been given to the geologically sensitive Narayanghat–Muglin section," he said.
According to the expert, the highway lies in an area where the Indian Plate continues to push beneath the Eurasian (Tibetan) Plate, making the region highly vulnerable to earthquakes. The collision of the two tectonic plates has weakened the rock formations and soil, increasing the risk of landslides.
"The engineering design of a highway built in such a geologically sensitive area should have been far more rigorous than that of roads in other regions. That level of attention appears to have been lacking," he said.
He added that the Narayanghat–Muglin section lies within the Main Central Thrust (MCT) and Main Boundary Thrust (MBT) zones—two major tectonic fault lines in the Himalayas. While the MCT marks the boundary between the Indian and Eurasian plates, the MBT separates the Mahabharat Range from the Chure hills. Both fault zones contribute to the area's geological instability.
The expert said infrastructure development in watershed areas should be carefully planned to avoid destabilizing slopes above the highway. Although road projects typically consider land extending about 25 metres on either side of the highway, he said geologically sensitive sections such as the Narayanghat–Muglin corridor require assessments covering up to 40 to 50 metres beyond the road corridor to minimize landslide risks.
