A review of hydro-meteorological hazard, vulnerability, and risk assessment frameworks and indicators in the context of nature-based solutions

Nature-based solutions (NBS) are increasingly being implemented as suitable approaches for reducing vulnerabilityand risk of social-ecological systems (SES) to hydro-meteorological hazards. Understanding vulnerabilityand risk of SES is crucial in order to design and implement NBS projects appropriately. A systematic literaturereview was carried out to examine the suitability of, or gaps in, existing frameworks for vulnerability and riskassessment of SES to hydro-meteorological hazards. The review confirms that very few frameworks have beendeveloped in the context of NBS. Most of the frameworks have emphasised social systems over ecological systems.Furthermore, they have not explicitly considered the temporal dimension of risk reduction measures. Thestudy proposes an indicator-based vulnerability and risk assessment framework in the context of NBS (VR-NBS)that addresses both the above limitations and considers established NBS principles. The framework aims to allowfor a better consideration of the multiple benefits afforded by NBS and which impact all the dimensions of risk. Alist of 135 indicators is identified through literature review and surveys in NBS project sites. This list is composedof indicators representing the social sub-system (61% of total indicators) and the ecological sub-system (39% oftotal indicators). The list will act as a reference indicator library in the context of NBS projects and will beregularly updated as lessons are learnt. While the proposed VR-NBS framework is developed considering hydrometeorologicalhazards and NBS, it can be adapted for other natural hazards and different types of risk reductionmeasures.