Vietnam – March 2020 

Bioengineering – or the use of vegetation to serve an engineering function – can constitute a low-cost option to supplement conventional infrastructure engineering design and increase resilience of local communities to the impacts of climate change and extreme weather events.

In March 2020, the Global Environment Facility (GEF) released a Good Practice Brief on Nature-Based Solutions (NBS) for erosion control based on the findings and experience of the project Promoting Climate Resilient Rural Infrastructure in Vietnam, administered by the Asian Development Bank and implemented by ICEM – International Centre for Environmental Management, which demonstrated bioengineering techniques for road and riverbank slope protection.

Two demonstration sites were installed on riverbanks in Bac Kan and Son La provinces, and two other sites on roadside slopes in Son La and Thai Nguyen provinces. All demonstration sites were co-located with sub-projects of the large Sustainable Rural Infrastructure Development Project which is building rural infrastructure with conventional designs.

Two years after project completion there were no signs of erosion at either of the demonstration sites despite several serious floods and intensive rainfall events. The bioengineering measures also provided social, economic and ecosystem co-benefits, for example engaging local communities in construction, repairs and maintenance and providing fodder and firewood.

Key lessons learned through the implementation of the project and highlighted in the brief include:

  • Bioengineering should be considered at the earliest stage of project planning
  • High risk locations need to be identified as early as possible using proven vulnerability assessment and slope condition criteria
  • Specific slope problems need to be identified and assessed using low-cost geotechnical investigation procedures
  • Integration of hard and soft measures need to be considered to solve problems where bioengineering alone is insufficient
  • Active engagement of local contractors and communities should be sought in designing the intervention, identifying suitable plant species, sources, replication methods and planting seasons and to monitor the project for maintenance
  • Considering social aspects are key to success. This includes identifying communities willing to host demonstrations, identifying demonstration sites with tangible community benefits, and reviewing plant options for their potential economic uses and local availability

While the project demonstrates the strong potential of NBS, sustained commitment will be needed to ensure the mainstreaming of these techniques in national design standards. The brief identifies several beneficial next steps which will support this goal. These include the establishment of a more extensive network of pilot demonstrations accompanied by development of technical standards and cost norms, and inclusion of bioengineering techniques in training curriculum for engineers.