Each monsoon, when highways close after heavy rain or traffic halts due to rock fall, we usually see only the immediate crisis. A landslide occurs, excavators move in, debris is cleared, and traffic resumes, until the next failure. We treat each landslide as a crisis to be managed, not a pattern to be understood. What often goes unnoticed is the deeper, recurring problem beneath these disruptions: Nepal’s highway maintenance system still focuses largely on pavement, while the slopes that physically support our roads receive little systematic attention.
Not every landslide can be prevented. Complex geology, extreme rainfall, shifting land use, and the interplay of natural and human forces will continue to trigger new failures. However, evidence indicates that proactive slope management and risk-based prioritization might have eliminated or significantly reduced a large portion of road obstructions and economic losses in Nepal. Over time, the country’s heavy reliance on emergency response has blurred the boundary between unavoidable natural hazards and avoidable institutional neglect.
The data increasingly make this clear.
A growing economic burden and a clear warning spike
Department of Roads (DoR) records for fiscal years 2077–2081 BS reveal a troubling trend. Roadside landslide incidents and road closures remained relatively stable between 2077 and 2080 BS, but escalated sharply in 2081 BS. In that single year, reported roadside landslide events exceeded 800, compared to roughly 250 in preceding years, an increase of more than 220 percent.
The economic damage was even more alarming. Estimated closure-based losses rose nearly fourfold in 2081 BS, surpassing Rs 4,000 crore. These figures primarily reflect the direct cost associated with road closures and do not fully capture wider economic disruptions such as travel delays, traffic congestion, supply-chain interruptions, and lost productivity.
This disparity matters. Nepal’s largest losses from landslides are not the costs of clearing debris or rebuilding damaged structures. They arise from immobilized movements including stalled freight, delayed services, and inflated transport costs. Nepal’s highways function as narrow economic lifelines. When they fail, the consequences ripple far beyond the landslide site, affecting regional and national economy.
Emergency response has become routine
Longer-term maintenance records reinforce the same pattern. DoR data for fiscal years 2069–2078 BS show total maintenance budgets rising steadily, alongside recurring emergency maintenance expenditure year after year, largely driven by post-landslide debris clearance and rapid traffic reopening.
There exists a difference in between identified needs and actual budget allocation for slope-related maintenance activities. DoR records show that demand for slope management, driven by aging protection works, expanding road networks, and increasing climate stress, has risen steadily over time. Yet allocations remain substantially lower, with no effort to close the gap.
This chronic underinvestment ensures that known vulnerabilities persist, gabion walls deform, wire mesh corrodes or tears, rock bolts loosen, bio-engineered slopes degrade, and over-steepened cut slopes remain untreated. Instead of being addressed through timely maintenance, these weaknesses are left to fail, only to reappear as emergencies, at far greater economic and social cost.
Why slopes matter as much as pavement
Nepal’s road network has expanded dramatically, from about 4,000 km in 1980 to over 100,000 km today. Nearly 80 percent of the country’s strategic roads traverse hills and mountains, where road performance depends more on slope stability and drainage than on the quality of asphalt.
The difference in consequences is fundamental. Poor pavement leads to uncomfortable travel and higher vehicle wear. Slope failure, by contrast, causes complete road closure, economic paralysis, and sometimes weeks of isolation for entire regions. In mountainous terrain, treating slopes as a secondary concern is not merely inefficient, it is dangerous.
Nepal has already invested heavily in slope protection works, including retaining walls, wire mesh, rock bolts, drainage channels, check dams, and bio-engineering measures. Yet these systems are rarely treated as maintainable assets. These are slow but visible processes, ignored until collapse forces costly emergency intervention.
The Narayanghat–Mugling road illustrates this problem clearly. Along this corridor, advanced slope stabilization structures and monitoring instruments were installed at considerable cost. Today, many monitoring systems are non-functional or no longer tracked, and upstream check dams designed to protect the highway are repeatedly damaged during monsoon seasons with little maintenance response. Similar patterns exist across Nepal’s highways, where expensive protective works gradually lose effectiveness due to neglect.
The issue is not only maintenance, but also prioritization. Each monsoon triggers dozens of roadside landslides, yet there is little evidence that budget demonstrate systematic risk-based prioritization: distinguishing which slopes are critically unstable, which pose high economic risk, and which can be managed through low-cost preventive measures. Without such differentiation, resources are spread thinly or deployed only after failure occurs.
An integrated approach to maintenance
International experience shows this cycle can be broken. Transportation agencies facing recurrent slope failures have adopted systematic slope management systems that integrate inventories, inspection schedules, condition databases, and predictive analysis.
Nepal’s own research on Himalayan highways points in the same direction. Combining pavement condition data with slope-failure susceptibility mapping using GIS allows smarter maintenance prioritization, by both functional importance and failure risk.
Four practical steps stand out.
First, treat slopes as assets. Every retaining wall, drainage structure, rockfall barrier, and check dam should be inventoried and tracked, just like bridges. Nepal already has technical guidance, including the DoR’s Guide to Road Slope Protection Works (2003), but these recommendations remain largely absent from routine maintenance.
Second, inspect systematically. Maintenance contracts should require regular slope inspections using standard checklists, enabling early detection of warning signs such as cracking, seepage, deformation, and drainage blockage.
Third, budget for prevention. Slope work should no longer be buried under “emergency maintenance.” Routine budgets must explicitly fund mesh repair, bolt tightening or replacement, vegetation management, erosion control, and minor stabilization work. Evidence consistently shows that every rupee spent on prevention saves several rupees in future repair and closure-related losses, especially in mountain highways where closure costs dominate.
Finally, the integrated system is a must. Pavement and slopes are managed by the same agency yet treated as separate problems. Integrated planning improves technical outcomes and makes better use of limited public resources.
Beyond pavement
The sharp escalation in 2081 BS should be treated as a warning, not as anomaly. Climate change is intensifying rainfall extremes, increasing the likelihood that small maintenance defects will turn into major failures. In mountain highways, pavement is merely the visible surface. Slopes are the foundation.
Until Nepal’s maintenance philosophy reflects that reality, roadside landslides will continue to surprise us, though the warning signs have been clear all along.
