The Bhutanese Leading the way.
The monsoon season in Bhutan, spanning from July to September, brings with it significant challenges for road infrastructure, leading to frequent blockages that disrupt travel and daily life. According to the Department of Surface and Transport (DoST), the Fiscal Year (FY) 2023-2024 recorded a total of 363 roadblocks across various highways, emphasising the severity of the issue.
Notably, the Regional Office (RO) in Sarpang reported the highest number of roadblocks, with 113 incidents, followed by RO Samdrup Jongkhar with 73 and RO Tingtibi with 56. In contrast, RO Thimphu reported the fewest blockages, with only 12 incidents, all occurring along the Primary National Highway (PNH). This distribution suggests that the southern regions of Bhutan are particularly vulnerable to road disruptions during the monsoon.
A closer analysis reveals that the majority of these roadblocks, 306 out of 363, are categorised as minor and typically cleared within 24 hours. For instance, Sarpang’s RO reported 17 major and 96 minor blockages.
The primary causes are attributed to heavy rainfall during the monsoon and occasional snowfall in the winter. An official from DoST said, “The roads in the southern part of Bhutan are particularly vulnerable to slope failures due to poor geological conditions exacerbated by heavy rainfall. Additionally, newly constructed roads may experience slope failures as freshly cut slopes require one to two years to stabilise.”
Landslides are the most frequent cause of roadblocks, with 241 incidents reported, followed by debris flows, which accounted for 57 roadblocks. Certain regions, particularly in the southern part of Bhutan, experience road blockages more frequently due to their geological and climatic conditions. Notable locations include Aie Slip along the Gelephu-Trongsa PNH, Boxcut along the Gelephu-Trongsa PNH, Ossey along the Gelephu-Trongsa PNH, Shawja, Sonam Ja, and Kezari along the Manitar-Lhamoizhingkhar PNH, Reotala along the Gelephu-Trongsa PNH, Stretches along the Gyelposhing-Nganglam PNH, Praling along the Tingtibi-Panbang PNH, Tsebar-Mikuri Secondary National Highway (SNH) and Khagochen along the Sunkosh-Dagana SNH.
While corrective measures have stabilised locations like Aie Slip and Khagochen, Boxcut remains a challenging site. DoST has developed a detailed project report for an alternative road alignment to bypass this chronic block location, with construction scheduled to begin this year.
The official from DoST said, “These locations frequently experience roadblocks due to their unstable nature and failure slip surfaces, which are challenging to address due to their large-scale failures. The geological and climatic conditions in these areas play a significant role in triggering these roadblocks. No suitable alternatives have been found at most of these locations because of very poor geological conditions requiring highly expensive solutions.”
Meanwhile, DoST said that they have been proactive in addressing these issues. For critical locations like Boxcut, an alternative road alignment is planned, with construction set to commence this year. Additionally, slope stabilisation projects, supported by the Japan International Cooperation Agency (JICA), have been implemented at several critical points along major highways, such as the Wangdue-Trongsa PNH and Phuentsholing-Samtse PNH.
These efforts are part of a broader strategy to improve the resilience of a country’s road infrastructure against climatic challenges. The ongoing World Bank project, Strengthening Risk Information for Disaster Resilience, also aims to create comprehensive hazard maps, which will aid in making informed decisions and planning effective interventions.
The official said, “Despite these measures, the mountainous terrain of Bhutan continues to present significant challenges, making it difficult to predict the frequency and exact locations of roadblocks. However, DoST remains committed to clearing roadblocks swiftly to minimise disruption.”
According to DoST, the road network in the country, especially its highways, has seen notable improvements through regular widening, maintenance, and enhanced drainage systems to mitigate road failures from heavy monsoon runoff.
Likewise, to address slope stability, DoST, with technical and financial assistance from JICA, has implemented several slope stabilisation projects.
DoST has undertaken initiatives, such as constructing a rockfall countermeasure at Tekizampa on the Wangdue-Trongsa Highway, and implementing bio-engineering works along the Wangdue-Chuserby and Phuentsholing-Samtse highways. These projects enhance the resilience of road infrastructure against climate-related impacts.
DoST is proactively adopting advanced, climate-resilient designs to better withstand monsoons and other climatic challenges.
