Sri Lanka is exposed to multiple hazards, such as violent tropical storms, flash flooding, and landslides. In 2017 alone, floods caused 213 deaths, damaged over 88,000 houses, and displaced over 100,000 people. As the country’s urban population has continued to expand, so have development and construction projects that sprawl on the periphery of major cities and transportation networks. These urban sprawl patterns have encroached on the island’s ecosystem of wetlands, which act as a highly effective natural barrier against floods and also act as natural air conditioners, water and air purifiers, carbon sinks, agricultural havens and safe harbors for biodiversity.

Sri Lanka’s hilly regions are also exposed to significant landslide risks, especially during the monsoon season. Poor communities living in these regions are especially vulnerable to these hazards. Many settlements in these high-risk areas were constructed decades ago and have not been maintained with professional construction practices. The National Building Research Organization (NBRO) has identified around 5,200 families (around 25,000 people) who live in high-risk areas and another 5,700 families (26,000 people) who live in settlements with moderate landslide risk.

To overcome the recurring challenges posed by flooding and landslides, the World Bank and the government of Sri Lanka have identified nature-based solutions (NBS) as cost-effective, eco-friendly, and sustainable measures that can be incorporated into risk management approaches. NBS makes use of natural processes and ecosystem services to address hazards such as floods, erosion, and landslides. The use of NBS has already achieved important successes in Sri Lanka, as evidenced in the capital city of Colombo, where wetland ecosystems have become an important solution for the flood-prone cities future. Following technical assessments carried out by the World Bank that showed that protection from flooding depended on the city’s natural wetlands, the Metro Colombo Urban Development Project protected and restored 20 square kilometers of freshwater lakes, wet woodlands, wet grasslands and swamps, offering a natural defense to flooding. In FY22, GFDRR provided financial support to communities living in areas exposed to landslide hazards to explore NBS mitigation measures and to enhance the capacity of local and provincial authorities to ensure the sustainability of the mitigated landslide sites completed under the country’s Climate Resilience Improvement Project (CRIP).

Thanks to the success of NBS initiatives in Colombo, the government intends to replicate wetland preservation across the country, with to date 49 development plans for conserving wetlands across Sri Lanka approved with 21 more in development. With regards to landslide hazards, multiple partner institutions—including the National Building Research Organization Sri Lanka (the mandated landslide mitigation entity in Sri Lanka), the Uva Provincial Road Development Department (PRDD; the Uva PRRD CRIP Implementing Agency), and the Central Province Education Department—received valuable data on the identification of areas and populations most at risk from landslides.

Key local stakeholders were sensitized to the value and advantages of NBS solutions, and a booklet highlighted strategies to mitigate landslide risks—such as bioengineering unstable slopes by planting new vegetation—was produced and distributed to Sri Lankan DRM practitioners and stakeholders.

National and local government agencies should routinely consider integrating NBS as either standalone or hybrid infrastructure approaches (or both) in regional and master planning. NBS should also be considered in land-use planning processes, such as river basin and urban development plans, as they offer an opportunity to bring down the costs of conventional engineering measures while providing an adequate level of safety. Moreover, government agencies should build productive supportive partnerships with approving bodies, civil society organizations, potential co-investors, and technical experts.