Case Study

Bioengineering in the Asia-Pacific  

Bioengineering offers a holistic approach to enhancing infrastructure and community resilience in the face of climate change. By harnessing the inherent strengths of nature-based solutions, engaging local communities, and reducing environmental impacts, bioengineering presents a powerful tool for building a more resilient and sustainable future.

The Asia-Pacific region faces the imminent threat of climate change and associated disaster events, such as floods, coastal erosion, storm surges, sea level rise, and landslides. Bioengineering has emerged as a nature-based solution to enhance the resilience of communities and infrastructure in the face of climate change and natural hazards, with the onset of climate change leading to growing demand in this sector. Bioengineering leverages the power of living plants and natural building materials to mitigate the impacts of climate change through carbon sequestration and other natural processes, whilst improving the long-term sustainability of infrastructure, for example in slope stabilisation and mitigating erosion risks. The Asian Development Bank (ADB) has implemented various such projects across Asia, including in Vietnam, Nepal and Bangladesh.

A subset of green infrastructure, bioengineering integrates vegetation into simple civil engineering structures. It relies almost exclusively on leveraging the power of living plants and natural building materials to reinforce infrastructure and absorb energy from water and wind, making it fully a nature-based solution. It aims to enhance infrastructure’s strength, flexibility, and ability to recover from damage over extended periods, typically at least ten years. This approach requires limited fossil fuel inputs than comparable techniques using ‘hard’ engineering only, lowering greenhouse gas emissions and contributing to climate resilience by reducing the carbon footprint of infrastructure projects.

One of the key advantages of this approach is the ability of the plants used in bioengineering to provide engineering functions to recover from damage. This inherent resilience, achieved through combination of plant and simple structures working together, ensures that bioengineered systems continue to perform effectively over time, even in the face of extreme weather events or other disturbances. Bioengineering also serves as an environmental mitigation measure to protect exposed surfaces and reinstate disturbed land, helping to restore ecosystems and biodiversity, and contributing to overall environmental resilience.

Techniques such as grass planting, brush layers and vegetated stone pitching, also provide cost-effective methods of surface protection for soil slopes. This surface cover of vegetation acts as armour, preventing erosion and soil degradation, which is crucial for resilience against any erosion and shallow landslides. Additionally, different types of plants and planting techniques in bioengineering produce varying rooting patterns. These root systems can bind or anchor the surface layer of soil, increasing its resistance to deformation and preventing shallow rills and deeper failures, enhancing overall stability.

Bioengineering techniques used by ADB have been primarily developed in hilly and mountainous environments, where they provide critical soil protection and stability. However, the versatility of these techniques allows them to be adapted to various terrain types, including plain areas (such as on embankments), and applicable in both rural and urban settings. Bioengineering is also a highly adaptable solution which can be incorporated in various sectors, including transport, water, urban spaces, and agriculture. It incorporates traditional and local knowledge and skills, making it an ideal candidate for community contracts or initiatives. Ensuring community involvement throughout these projects is crucial to their success, with training and capacity building of the local community being paramount to enhance the community’s ability to build and maintain the infrastructure, as well as to empower them to adopt similar methods in other projects.

Engaging local communities in bioengineering projects not only improves the resilience of infrastructure but also creates employment opportunities and fosters community ownership. This is evidenced, for example, in Vietnam where during a project on erosion control[1] (see Box X), the capacity and technical skills of 179 Vietnamese government personnel were improved along with university staff and students, and local communities. Rural community involvement also helps to ensure that the bioengineering methods used are appropriate to the local landscape, ecology, and culture. Following construction, residents can be more involved in the maintenance of bioengineered sites, using their skills in farming and forestry. These projects also have considerable inclusivity and wage benefits, and often include a large portion of women and ethnic minorities in the labour force. Moreover, if the plants used for bioengineering can have economic value as timber, fodder, grass or other commercial uses, bioengineering can support income generation and improved livelihoods of the local communities engaged in implementation and maintenance of the bioengineering works.

Bioengineering techniques are cost-effective, inclusive and are often proven to be significantly more economical than conventional engineering-based interventions. In the specific case of a slope-stabilisation project in Vietnam (see Box X), it was found that bioengineering methods incurred construction costs that were merely 10-23% of what conventional techniques would have required. This cost reduction translates to substantial savings, allowing for the allocation of resources to other vital community needs. Bioengineering’s ability to deliver resilience at a reasonable cost makes it an economically prudent choice that is accessible to a wide range of infrastructure projects, particularly in regions with limited financial resources. This makes bioengineering solutions one of the low-hanging fruits for implementing measures to improve climate resilience.

Promotion of bioengineering requires efforts at the policy level to establish or upgrade relevant guidelines, including norms and standards. To support this, the ADB has adopted and published guidance, standard specifications and courses intended to inform policymakers and practitioners. However, to realise the potential of bioengineering fully, this work must be taken on by a wider range of national and local governments and organisations, as well as academia.

Protecting roadside slopes and riverbanks in Bangladesh

The ADB has also been promoting bioengineering technologies by providing technical and financial support as a package to ADB’s developing member countries. This work is ongoing and will continue for the foreseeable future. For example, the ADB has implemented a project in Bangladesh to improve the stability of existing slopes and the construction and maintenance of roads to prevent landslide risks. This intervention was to help in mainstreaming nature-based solutions through roadside bioengineering, in government policies to inform and complement overall project design and implementation. With associated engineering options, roadside bioengineering can increase the resilience of roads to extreme climatic events by providing the surface protection of roadside slopes and riverbanks.

Erosion Control in Vietnam

This project demonstrated and promoted the application of bioengineering measures in road and riverbank slope protection and stabilisation to build the resilience of local communities to the impacts of climate change and extreme weather events. This included implementing four successful bioengineering interventions at four riverbanks and roadside slope sites and preparing landslide and flash flood risk maps for Son La and Bac Kan provinces. As an outcome of this project, four riverbank and roadside bioengineering demonstration sites were completed. After several years, these pilot sites proved that slope and embankment protection has increased community resilience to events such as extreme flooding. The bioengineering methodologies also created local employment and provided other benefits such as fodder, building materials and medicinal plants, and established aquatic and terrestrial habitats for plants and animals.

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