Roads are one of the most significant components of a country's development. They make the first impression when tourists or foreigners visit a country. Roads are the backbone of a nation's prosperity and beauty in the world. Whether it's economic growth or rural, regional, or urban development, roads play a fundamental role. Roads are vital for agricultural development, social and cultural exchange, tourism, educational and health access, and much more. Hence, the significance of roads in today's world is profound and cannot be adequately summarized within the scope of this brief piece. As a former American president stated, "Roads are the arteries through which the economy pulses."
Now, let's move on to the conditions and life of roads in Nepal. Let's examine some of the critical aspects of roads and their condition over the years. In general, and in most cases, we can say that Nepal's roads are infamously unsafe. But why? Let’s delve deeper into the reasons behind this, and also let’s search for what can be done to minimize these problems.
Till September 2024, approximately 101,513 km of roads have been built which includes 34,267 km of national roads and 67,246 km of local roads. And most of the roads are located in the hilly area as there are many hilly areas, and we need to build more roads in that area. So, the key point in the discussion of roads in Nepal is its geographical vulnerability.
Let’s look at two headlines: one from BBC on September 29, 2024, which says, "All roads connecting the capital are blocked due to floods" and another from Ratopati on July 6, 2024, which states, "All roads leading to Pokhara are blocked, landslides on six major roads of Gandaki." As we all know, Kathmandu and Pokhara are considered the most important and developed cities in Nepal. However, during the same year, and at different times, all the ways leading to these cities were cut off, thus isolating these big cities from the rest of the country . What challenges are our roads facing, and where are we going wrong?
Monsoon rainfall in Nepal is primarily caused by clouds originating from the Bay of Bengal and the Arabian Sea. In the present year at more than 25 stations, the highest rainfall was recorded in Nepal in the history at the end of the monsoon continuously for 48 hours (September 26, 27 and 28). The three days of rainfall caused huge damages across the country, resulting in an estimated economic loss of 17 billion rupees
All the highways connecting Terai to Kathmandu (B.P. Highway, Kanti lokpath, Prithvi Highway, Kulekhani Road, etc.) were blocked due to floods and landslides, with bridges and roads washed away. The nation suffered a Rs 4 billion loss in the energy sector, Rs 3.5 billion in the water supply sector, Rs 2.52 billion in roads, and Rs 1 billion in irrigation. Chief Secretary Eknarayan Aryal said floods and landslides damaged 37 highways, 16 hydropower projects with a capacity of 664 MW, 312 telecom sites, and five major transmission lines. The Armed Police Force reported 238 fatalities and 29 people as missing. As many as 1,769 houses and 55 bridges were totally damaged.
In high-risk areas, it’s essential to stabilize both the upper and lower surfaces of the ground but the concept of green road is highly effective in every region.
Even though the Meteorological Forecasting Division (MFD) had previously warned of a heavy rainfall for September 26, 27 and 28, the Ministry of Home Affairs reportedly failed to take adequate precautionary measures. The concept of floodplain is not practiced well. Twenty meters on both sides of the river should be left free for floodplain, but in Nepal, especially in the Kathmandu Valley, instead of floodplain there is the practice of a corridor road, which is a very bad practice in engineering. There is no recharge zone in the Kathmandu Valley. All the lands were concrete, and then the water was unable to infiltrate the ground and flowed toward the river, i.e., all the water was runoff causing serious damage to lives and properties. Had this rainfall occurred at the start of the monsoon, it might not have damaged to this extent because some amount of rainfall infiltrated into the ground and the remaining may occur as runoff. According to experts, the soil's infiltration capacity reaches its maximum due to previous rainfall at the start of the monsoon season in Ashar, Shrawan, and Bhadra (Nepali months).
As a result, a smaller percentage of rainfall is absorbed, and a larger percentage contributes to runoff, causing heavy floods in rivers. The main cause of such natural calamities is development that is done in an irregular manner, disturbing the natural condition of the environment. Human settlements, farming areas, open zones for recharge, factories, hospitals, and markets should all be strategically planned and located to minimize their vulnerability to natural calamities. Infrastructural development should be initiated with the planned way plus centralized engineering with eco-friendly development. The bridges collapsed due to the bad engineering practice. By using Gumbel’s law , the return period and probability of the flood can be calculated from which the bridge should be designed for this return period by adding some safety margin. But in Nepal, it seems that this practice has not been implemented properly.
On the morning of June 28 along the Narayangadh-Muglin road section, two buses were washed away, apparently to due to poorly built local roads, and improper management of stone quarries, according to experts. Experts believe that if these activities had been done correctly, the incident could have been prevented. This has been a serious problem for several years. The local government owns its own dozer, and a large amount of excavation occurs improperly in hilly areas and near highways, which ultimately weakens the stability of the ground surface. There are also many areas where multiple roads are built on a single hill, one above the other, without conducting a geological survey. Examples of this can be seen in areas like Lalitpur and Makwanpur. An Initial Environmental Examination (IEE) and Environmental Impact Assessment (EIA) must be conducted for different lengths of roads as per the new guidelines. For example, any new road longer than 25 km requires an EIA. However, both the local and central governments are failing to implement these criteria effectively.
Two years ago, an organization called Oxford Policy Management conducted a study on "Landslides, Road Construction and Disaster Risk Reduction in Nepal's Land Policy" and concluded that 61 percent of the landslides in 35 districts across the country in 2077 BS were caused by roads. Similarly, a study conducted in 300 local levels of the Himalayan and hilly areas in 2075 BS, except for Terai Madhesh, revealed that 51 percent of the water source has dried up due to random construction of roads and buildings in the name of development (Kantipur).
We often focus only on the length and width of the road. However, the walls of the road play a vital role as well. While we focus on increasing road dimensions, the condition of supporting walls is consistently overlooked. Engineers have to make a proper study while widening the road in hilly areas. Prioritizing only the surface of a road neglecting the surrounding walls can lead to significant issues. And to expand or widen the roads, walls are often cut in straight 90-degree angles neglecting the crucial need for retaining walls or other support structures. This practice is detrimental in civil engineering as these unsupported vertical cuts can destabilize the soil above.
According to Dr. Ranjan Kumar Dahal, a geologist, the guidelines for cutting the road wall are wrong. There is a practice of cutting the mountain rock and placing a normal towel on the bottom and leaving it on top. This approach is flawed and leads to landslides even during the moderate rainfall (Gorkhapatra). For hard rock, a vertical cut is acceptable, but due to carelessness and corruption, vertical cuts are also made in weathered rock. When it rains, water wets the weathered rock, causing it to slide and potentially destroy the entire road.
In engineering, the concept of slope stability is that the shear strength of soil must be greater than the shear stress for a stable slope. The causes of slope failure are either due to an increase in shear stress on slope or a decrease in shear strength of soil on the slope. Rainfall significantly contributes to increased shear stress on slopes. As rainwater flows downslope, seepage forces increase, leading to higher shear stress and subsequent erosion. This continuous erosion process gradually steepens the slope inclination. Also, some other causes are dynamic loading like earthquakes and load increments in slope. Now for the decrease in shear strength of soil on slope, the main causes for here also are raining by wetting the soil particles and reducing friction and other causes like dynamic loading and weathering of rock on a slope.
There are many preventive measures for slope failure. The first and most important is reducing the slope's inclination by cutting and filling. The main factor that causes ground surface movement or landslides is water flow, which increases pore pressure, thereby decreasing the soil's shear strength and ultimately causing soil movement due to active earth pressure. And when soil saturates it becomes heavier and more likely to slide. Therefore, the primary mitigation measure for landslides along roads is a proper drainage management system.
Another important measure is reducing the load on the slope and ensuring a proper water drainage or management system. However, bioengineering and retaining walls are not the only solutions. In high-risk areas, it’s essential to stabilize both the upper and lower surfaces of the ground but the concept of green road is highly effective in every region. Efforts to prevent landslides in the Krishnabhir area along the Prithvi Highway have proven effective through the planting of bamboo, babio and various grasses. This natural approach is effective as well as economical. Countries like Japan have implemented extensive bioengineering techniques, known as sabo technology, to prevent landslides along the roads. Also, some sensing and advanced monitoring technologies can be applied in highly risky zones which have been in practice for a long time in countries like Spain and Italy.
One of the most critical problems Nepal faces is the lack of good alternatives to the main highways. For example, the Nrayangadh-Muglin road is one of the busiest and significant highways in Nepal. But every monsoon the road gets damaged and thousands of people face problems. Several thousand vehicles (more than 20,000), including large load-carrying vehicles, travel this road daily. To provide more viable and effective options to the highway, several alternative links could be developed. For example, the Gaindakot-Devghat-Dashdunga Muglin road or the Bhandara-Malekhu may serve as alternatives. Now the Terai-Kathmandu fast-track is also a good alternative for the Narayanghat-Muglin road. Also there has not been any good alternative road constructed for the BP highway either.
Over time highway walls and other structures get damaged because of the vibrations emitted by vehicles carrying loads heavier than the prescribed threshold but the periodic checks and strengthening have not been frequently done. The Prithvi Highway, which was opened in 2031 BS, has not received repairs to the walls, except for regular maintenance in 2048 BS. The East-West Highway, which was built in 2042 BS, has received only minor maintenance repairs despite extensive damages (OnlineKhabar).Weather conditions like extreme fluctuation in temperature , snowfall, rainfall can cause expansion and contraction and the materials used in road construction like asphalt degrades over time. Hence, maintaining highway infrastructure requires continuous monitoring. According to international practice, every highway should be reconstructed in seven to 10 years.
Nepal's complex geography requires a more comprehensive and cautious approach to road construction and maintenance. More attention has to be given to safety issues, engineering practices, and lessons learned in order to develop a more effective and reliable road network.
In a country like Nepal, where the geography is complex, road construction is a highly sensitive project, as any negligence can lead to major landslides. In areas like the Terai region or states like UP and Bihar in India, the terrain is mostly flat, providing significant advantages for road construction since there is minimal need for work on slope stability and retaining walls. However, in hilly regions, roads must not be constructed without thorough hydrological and geological studies and engineering. Unfortunately, this is not being done on a large scale, which is why problems arise over time.
Many experts say that even our design standards of national highways are not such as to protect against floods and landslides. A Detailed Project Report (DPR) must be completed before any road construction. However, many roads, especially rural roads, were constructed without a proper DPR. Even for main highways, although a DPR was prepared, it was flawed. The Narayangadh-Muglin project has admitted that the DPR is flawed. In the original DPR for the road, only a few bioengineering measures were suggested, but these measures were insufficient, which is why problems arise from time to time. So, the Narayangadh-Muglin road section does not appear to have undergone sufficient engineering processes. During its initial construction, China built it as a single-lane road, but later it was widened without proper geological study of the area. Many experts agree on this point. Many highways in the country are not an exception to this case.
Rock falling is also one of the main challenges on many roads like the Araniko Highway connecting Nepal and China. And nowadays rock netting and rockfall barriers are highly effective techniques to mitigate this problem. For prevention of slope failure on rock slope, rock bolting (for layered rock) and wire netting (for weathered rock) are effective ideas. Rock netting involves the installation of wire mesh or netting systems on rock slopes to prevent loose rocks from falling onto roads or populated areas. And it's good to see that these techniques are now being implemented in areas like the Siddhababha region and other locations.
In hilly areas, constructing roads often destabilizes the ground, hence increasing the chances of landslips and falling of rocks. Tunnels bypass these unstable slopes, which minimizes any chance of landslides. Tunnels provide shelter from extreme weather conditions such as heavy rain, snowfall, or strong winds, which are common in hilly areas. Developed countries with similar geography, like Japan and China, have already entered the tunnel era. We are also gradually moving in that direction, with projects like the Fast-Track being among the biggest and most essential developments in road infrastructure in Nepal.
In a nutshell, Nepal's complex geography requires a more comprehensive and cautious approach to road construction and maintenance. More attention has to be given to safety issues, engineering practices, and lessons learned in order to develop a more effective and reliable road network. It's now crucial to focus on the highways in our hilly areas. We need to consider rerouting, alternative roads, or implementing effective preventive measures based on thorough geological and engineering studies. We are still in the development phase and we are considerably behind other countries in terms of progress and development, so we must take action quickly and systematically.
(Ronish Sapkota and Bidur Ghimire pursuing their Bachelors of Engineering at IOE, Pulchwok Campus and IOE,Thapathali Campus, respectively.)
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