Resilience Assessment Framework for Nature Based Solutions in Stormwater Management and Control: Application to Cities with Different Resilience Maturity

Cities face unprecedented demographic, environmental, economic, social, and spatial challenges. In recent years, the implementation of nature-based solutions (NBS) is becoming more relevant in cities to improve urban resilience and to cope with climate change. NBS represent cost effective solutions that simultaneously provide environmental, social, and economic benefits and help build resilience. A comprehensive and multi-dimension Resilience Assessment Framework (RAF) to evaluate the NBS contribution to urban resilience, focused on NBS for stormwater management and control, was developed. This RAF is aligned with the RESCCUE RAF and the main assessment frameworks focused on NBS and urban resilience. This RAF for NBS is driven by the definition of resilience objectives and is able to evaluate short- and long-term changes, considering a comprehensive definition of the urban resilience and addressing the environmental, social, and economic capabilities. Regarding the initial resilience maturity and the available information in the city, three analysis degrees were proposed for the RAF application, namely, the essential , complementary , and comprehensive degrees, for which a pre-defined selection of metrics is proposed. This paper aims to present the application of the RAF essential analysis degree and its extensive validation regarding cities with different resilience maturity and available information. The application to seven cities with different resilience and NBS challenges allowed an in-depth validation of the pre-defined metrics included in the RAF essential analysis. In this sense, the analysis of the resilience maturity of the participating cities is presented, the main challenges and consolidated aspects in the cities are identified, and the cities ready to apply the complementary analysis degree are recognized. To conclude, to validate the essential analysis degree, the assessment of the main requirements of the RAF for NBS are verified, based on the RAF metrics results for the cities. In this light, the main requirements of the RAF for NBS were aggregated in three main categories, namely, NBS aspects, resilience capabilities, and the performance, risk and cost analysis.