Integrated Approach Mitigates Landslides

As the monsoon season brings heavy rains to Nepal, the country becomes more exposed to one of its most common natural disasters: landslides. Landslides, a natural phenomenon that has shaped Nepal's mountainous landscape for ages, are now posing an increasing threat to the country's infrastructure, economy, and civilian safety. 

In recent years, the frequency and intensity of landslides have increased, with disastrous results. This concerning trend has been attributed to a combination of natural and human caused factors, including climate change, deforestation, unplanned development, and substantial road construction in sensitive terrain. A landslide is the downhill movement of rock, soil, and debris along a slope, caused mostly by gravity. This natural process can occur unexpectedly, with devastating consequences, especially in areas with steep slopes and fragile geological structures. Nepal, with its varied geography and active tectonic background, is especially vulnerable to such catastrophes.   

Natural triggers

A comprehensive study of landslides in Nepal found that steep slopes, intense monsoon rains, and the Himalayas' underlying geological structure are the key natural triggers. However, human actions have worsened the situation. The development of rural roads without sufficient engineering studies, deforestation for agriculture, and haphazard settlement expansion on susceptible slopes have all led to a rise in landslides.    

The human toll from landslides is astounding. Every year, hundreds of people are killed and many more displaced. The economic impact is as significant, with infrastructure, farm, and property destruction totalling millions of rupees. For example, during the 2024 monsoon season, Nepal saw a series of devastating landslides, killing over 50 people and displacing over 18,000. The interruption of transportation networks, particularly in steep and mountainous areas, has further isolated communities, making rescue and relief efforts difficult.  

The impact on agriculture, a vital part of Nepal's economy, is equally significant. Fertile grounds are frequently buried in debris, and irrigation systems are damaged, resulting in lower agricultural output and food insecurity in impacted communities. Furthermore, landslides can cause secondary disasters, such as floods, exacerbating the damage and making recovery even more difficult.    

Climate change has emerged as a significant contributor to the rising frequency of landslides in Nepal. The country's monsoon patterns have become increasingly irregular, with periods of heavy rain followed by dry spells. These erratic weather patterns destabilise the landscape. Intense rainfall saturates the soil, increasing its weight and decreasing its cohesiveness, making slopes more likely to crumble.   

Furthermore, the rising temperature accelerates the melting of glaciers in the Himalayas, resulting in the formation of glacial lakes. These lakes are frequently unstable, and their abrupt outbursts can cause landslides and floods downstream, endangering populations in the region.  Unplanned and poorly controlled development operations have contributed significantly to Nepal's landslide disaster. The rapid construction of road networks, particularly in rural regions, has been cited as a major contributor. Many of these roads are built without sufficient geological surveys or engineering controls, which causes slope instability.   

Using heavy machinery such as bulldozers in road construction makes the situation worse by increasing the risk of land instability and environmental damage. The excavation and cutting of slopes produce loose debris and weakens the terrain's structural integrity, making it more vulnerable to landslides during heavy rainfall.  

Similarly, unplanned urbanisation, particularly in mountainous areas, has resulted in the construction of structures and villages on unstable terrain. The absence of effective land-use planning and construction code enforcement has resulted in structures being built in landslide-prone locations, endangering residents' lives.  

Addressing landslides in Nepal needs a comprehensive approach that includes scientific research, careful land-use planning, infrastructure development, and raising community awareness. One key strategy is to create landslide hazard maps. These maps help identify areas at risk of landslides and can guide where to avoid or limit development. They can also inform the safe placement of roads, buildings, and other essential structures. 

Disaster preparedness

Reforestation and planting new trees can help make slopes more stable and reduce soil erosion. Trees with deep roots hold the soil together, lowering the risk of landslides. Additionally, keeping natural vegetation intact helps protect the land from heavy rains. Improving drainage systems in landslide-prone areas is also crucial. Good drainage prevents water from building up in the soil, which reduces the chance of landslides. Engineering solutions like retaining walls, terraces, and special materials can also strengthen slopes. 

Community-based disaster preparedness programmes are vital. Educating local people about landslide risks and the importance of early warnings can save lives. Involving communities in hazard mapping and planning ensures their knowledge and needs are included in mitigation efforts. In summary, Nepal faces many landslides due to steep hills and heavy rain, but we can reduce the damage with smart planning. By using better building methods, protecting the environment, and helping communities prepare, lives and homes can be saved. Nepal needs to focus on development that is safe and mindful of nature. This means balancing progress with safety to protect people from future disasters. 

(Khadka is executive director of Nepal Physical Society and Baniya is B.Sc Physics student)