Introduction More countries are now considering the use of bioengineering in road infrastructure design and natural hazard work due to its positive impact on climate risks. Techniques, such as retaining walls, anti-erosion, and riverbanks protection built with natural materials, offer environmentally friendly, innovative, and sustainable solutions for managing, preventing or lessening the damage from slope instability, soil erosion, landslides, rock falls, debris flows, avalanches, forest fires, and floods. Bioengineering offers several advantages. The hiring of local firms boosts small countryside economies. By avoiding the use of steel and concrete and the transportation of materials over long distances, bioengineering techniques also reduce costs and carbon dioxide emission during construction. Natural materials (e.g., wood, logs, stones, rock, live vegetation) are generally available in the vicinity of the project sites. These require minimal maintenance for the first few years, and result in improved efficiency through the development of natural processes like vegetation regrowth. The positive effects of these techniques include the increase in the resilience of rural communities to unforeseen calamities and preserving ecological biodiversity (flora and fauna). With the highly variable climatic and natural conditions in Kazakhstan’s various geographic regions, the government sought the Asian Development Bank’s assistance to study the possibility of using bioengineering techniques in infrastructure design as part of preparations for the Saryagash Bypass Road project. Bioengineering for Road Design The study, which covered existing roads in the southeastern regions of Kazakhstan, indicated that natural hazard risks in road construction can be addressed through bioengineering techniques such as improving slope stability, addressing snowdrifts, and flood control depending on climatic and geological conditions of the region. These techniques provide added value by reducing greenhouse gas emissions from construction operations. Double log wall-retaining structures combined with live vegetation and drainage ditches for slopes could be used to stabilize road cuts or excavations in the Osinovski Pass Road, since it is in a mountainous area where logs are easily available. Geometrical design and live vegetation can be used for roads going to Taraz by using trees as live barriers to address long road closures during the winter season due to snowdrifts. Green embankments can be considered for rockfall protection on the Saryozek–Koktal road which goes through the mountains. The reinforced earth structures can be built with materials easily found on site. For the Saryagash bypass project that crosses almost flat, semi-arid land, bioengineering is suitable for flood control by water management techniques (e.g., infiltration ditches and temporary water ponding for agriculture), which use road embankments as “dams” for temporary water storage if the structure conditions allow these. While bioengineering is applicable in many Kazakhstan road projects, others still need traditional grey reinforcing works. For example, applying bioengineering in slope stabilization works depends on the availability of wood as construction material, which is rare in many regions of the country. Bioengineering for Flood Control Considering Kazakhstan’s climatic conditions, the study found that bioengineering techniques for flood control can be applied to several cases. For example: (i) road embankments can be adequately designed to retain water from scarce precipitations in semi-arid areas; and (ii) flood water should be retained, rather than discharged, for reuse during drought periods and to limit river flow peaks during heavy rains. These can be adopted in both urban and rural areas. Other techniques to consider include rainwater harvesting and attenuation storages, tree planting, filter strips and drains, detention basins, green roofs, and infiltration systems (Figure 1). Figure 1: Bioengineering for Flood Control Source: ADB. Conclusion Bioengineering use is continuously growing as it provides flexible ways to adapt to variable geological and climatic conditions for infrastructure. The flexible use of bioengineering for flood control and water management presents many opportunities in Kazakhstan. It can address a wide range of issues, such as drainage improvement and snowdrift mitigation. The techniques are best applied to small projects that can produce significant advantages to local communities in remote areas—bringing positive social, economic, and environmental impacts. In the past, Kazakhstan's road design specialists used the term "landscape gardening" for bioengineering. However, its practical application was limited due to its generic approach with no clearly defined specifications. There should be learning opportunities for road designers to analyze and justify the use of these techniques. The ADB-supported study provides examples of detailed technical specifications for a double log wall-retaining structure and live stack insertion. It also provides examples for potential designers to estimate the cost of using bioengineering. It would be helpful to develop a guide for road sector professionals to enhance their skills in using bioengineering in the design and construction of Kazakhstan’s roads. The guide could include requirements customized for each geographical region, and might be useful for the road design and engineering community at large designing new climate resilient roads. It would also support the country's efforts in improving the quality of climate resilient roads. Resources F. Oboni, et al. 2006. Environmental Restoration of a 60Mm3 Dry Asbestos Tailings Dump Using Risk-Based Decision Making. Canadian Land Reclamation Association Reclamation and Remediation: Policy to Practice. 31st Annual Meeting and Conference and 9th Meeting of the International Affiliation of Land Reclamationists. F. van Steenbergen, et al. 2021. Green Roads for Water: Guidelines for Road Infrastructure in Support of Water Management and Climate Resilience. Washington, DC: The World Bank. International Union for Conservation of Nature. 2020. Guidance for Using the IUCN Global Standard for Nature-Based Solutions. A User-Friendly Framework for the Verification, Design and Scaling Up of Nature-Based Solutions. First Edition. Gland. N. Gonzalez-Tarrio, et al. 2021. Improving the Performance of Linear Assets through Green Infrastructure. Main Guide (Phase 2, C772). London: Construction Industry Research and Information Association. Ask the Experts Claudio Angelino Natural Hazard and Nature-Based Solutions Expert Claudio Angelino is a civil geotechnical engineer with experience in studies, design and site supervision of complex natural hazards mitigation works for infrastructure. He has been involved in several ADB projects as road or geotechnical specialist and has worked in more than 15 countries. He has also been a member of the panel of experts set up by the European Union Technical Assistance Cooperation program to investigate the safety of dams in the Lao People’s Democratic Republic. Gulnaz Iskakova Digital Technologies Expert in Agriculture Gulnaz Iskakova focuses on the application of digital technologies in agriculture. She has consulted and coordinated projects for the Asian Development Bank, Michigan State University, American Soy Association, Kazakh National Agrarian Research University, Ministry of Agriculture of Kazakhstan, and Food and Agriculture Organization of the United Nations. She is currently a PhD student at Kazakh National Agrarian Research University where her thesis focuses on the development of the agro-industrial market in the context of food and water security in the Akmola region as example. Follow Gulnaz Iskakova on Asem Chakenova Senior Project Officer, Kazakhstan Resident Mission, Asian Development Bank Asem Chakenova supports Kazakhstan’s infrastructure operations, including transport. She is a member of ADB’s road sector and urban infrastructure projects, and involved in knowledge exchange and collaboration initiatives and mobilizing ADB resource assistance. She participates in all stages of ADB’s project cycle—from country assistance programming, loan and technical assistance processing to implementation. Asian Development Bank (ADB) The Asian Development Bank is committed to achieving a prosperous, inclusive, resilient, and sustainable Asia and the Pacific, while sustaining its efforts to eradicate extreme poverty. Established in 1966, it is owned by 68 members—49 from the region. Its main instruments for helping its developing member countries are policy dialogue, loans, equity investments, guarantees, grants, and technical assistance. 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