Resilient roads: protecting critical lifelines in mountainous Tajikistan
By Daniel Kull, Ko Takeushi, Marinos Skempas, and Faridun Sanginov
Driving through mountainous terrain can be challenging anywhere in the world. With limited space for straightforward routes, winding mountain roads are often forced to traverse hazardous topography. In addition, these roads tend to be difficult to maintain, especially in very remote valleys, and suffer from constant wear and tear. This is especially true in Tajikistan, where 93 percent of the territory is covered by mountains and where summers are very hot and winters very cold due to its continental and semi-arid climate. Not surprisingly, roads in Tajikistan are constantly deteriorating and are often impacted by floods, mudflows, rockfalls, landslides, avalanches, and earthquakes.
When roads are damaged by natural hazards, the cost is far more than just the effects on the infrastructure. Lives can tragically be lost, and timely emergency response and reconstruction are needed. At the same time, temporary diversions of traffic impede drivers and slow down trade, especially when alternate routes are not available or practical, as in Tajikistan. Road interruptions can also cut communities off from critical services and markets, leading to a loss of access to income opportunities and social, health, and educational services. In high-risk settings common in mountainous areas, successive and regular disasters often compound these impacts.
In July 2015, a series of extreme events, including floods and mudflows, in Tajikistan’s most remote and mountainous region, the Gorno-Badakhshan Autonomous Oblast (GBAO), destroyed several bridges, interrupting key transport corridors and stranding villages. The World Bank has been supporting the Ministry of Transport to rebuild 17 of these bridges though the Strengthening Critical Infrastructure against Natural Hazards Project. Located in the Pamir Mountains with peaks over 7,000 meters, most of these bridges will re-open to traffic this year, and all have been rebuilt to be more resilient than before, following the principle of “build back better.”
Yet, just rebuilding and reinforcing damaged bridges is not enough. The Ministry of Transport, local road authorities, and road users need to understand where the main road hazards are, what can be done to reduce the risks, and what options are the most cost effective. To support this, the World Bank and the Global Facility for Disaster Reduction and Recovery (GFDRR) recently completed an Assessment of Economic Impacts from Disasters Along Key Corridors. This was supported by the Japan-World Bank Program for Mainstreaming Disaster Risk Management in Developing Countries, which is financed by the Government of Japan and managed by the GFDRR.
Despite some mobility constraints due to COVID-19, in 2020 assessment teams surveyed over 2,000 kilometers of roads, identifying and closely inspecting more than 330 individual locations highly exposed to natural hazards. This was complemented by reviews of local and satellite data, maps, reports, and statistics, as well as interviews with local stakeholders, ministries, departments, and regional road maintenance organizations. Of the inspected sites, 36 percent are threatened by mudflows, 31 percent by avalanches, 13 percent by rockfalls, 10 percent by flooding, 8 percent by landslides, and 3 percent by erosion.
What is more, Tajikistan is expected to be hard hit by climate change, with projected increases in temperature, extreme precipitation, and droughts. Heavy rains will likely lead to a rise in the number of mudflows and floods, and more intense snowfalls may lead to more avalanches, especially when combined with more frequent warm spells. Potential later seasonal onset of freezing temperatures and earlier onset of thaws will increase the risk of slope instability, landslides, and rockfalls. In the longer term, the thawing of mountain permafrost might become a serious threat to road transport infrastructure. More extreme weather generally will accelerate the deterioration of roads by eroding pavement integrity, weakening bridge foundations and expansion joints, and overloading existing drainage systems.
To increase the resilience of the roads against these hazards, the assessment proposes several different types of protection measures, including: avalanche galleries, snow barriers, retaining walls, flexible rockfall barriers, rockfall drapes, debris flow barriers, larger culverts, strengthened bridges, road realignments, replacement of soft/swamp material, roadbed raising, and surface water drains. This national suite of resilience investments protecting over 2,000 kilometers of key roads would come at a high cost, however, estimated at just over US$400 million. To help Tajikistan determine which of the proposed road resilience investments make financial sense, the team also evaluated the potential socioeconomic benefits.
Based on official statistics, 400 household surveys, and 15 key informant interviews, it was determined that total economic damage due to disasters on the road network is currently about US$45 million per year, or 0.5 percent of the national GDP. This is expected to rise to about US$80 million per year over the next decade. In this vulnerable mountainous context, roughly one-third of these losses stem from communities being severed from public services and livelihood opportunities. Through a cost-benefit analysis, the benefits of eliminating these losses were compared to the costs of the proposed suite of road investments. It was found that though it was not economically viable to implement the entire set of suggested measures, specific solutions on certain road sections would make economic sense.
All of the proposed resilience investments support physical infrastructure, some of which are very expensive due to the large amount of construction involved. For example, the 65 proposed avalanche galleries cost on average over US$4 million each and would generally protect only very short (albeit critical) road points (on average 175 meters). On roads with limited traffic and/or only a small number of disasters, these kinds of investments simply do not produce enough economic return. Instead, solutions that do not involve infrastructure investments may be more economically sound. Particularly for avalanches, this could include, for example, improved hazard monitoring and forecasting to temporarily close roads during high-risk periods.
Although the Government of Tajikistan will determine which road resilience measures to prioritize and pursue, the report also recommends that investment in improved emergency preparedness and response, including search and rescue capabilities, continue. Equally important are investments in warning systems to detect the early signs of a potential hazard and to warn road users, at-risk communities, and first responders to be ready. These systems are more economically viable, and by ensuring that people are in the right place at the right time, they would also enable faster response times to disasters and thus reduce loss of life—the most important goal.