At present, the Sponge City Concept (SCC) is gaining ground, Sponge Cities technologies are becoming more and more accepted by Chinese city governments, and the first best practices are being shared. However, there are still many challenges ahead which hamper effective implementation and upscaling. This paper presents an overview of some opportunities and constraints for the take up of this approach and has drawn upon international experiences. In China at the national level, the State Council has set a progressive target for the SCC initiative to be achieved in 2030. This target seems to be ambitious as the time needed for integrative planning and design and implementation is much longer than traditional sectoral approaches often omitting to address social well-being, the (local) economy, and ecosystem health. This particularly holds true for the existing building stock. Transforming the existing building stock requires a long-term planning horizon, with urban restoration, regeneration, and modernization being key drivers for adapting the city to become a sponge city. A key challenge will be to align the sponge city initiative (SCI) projects with infrastructure and urban renovation portfolios. Moreover, substantial investment needs and a lack of reliable financing schemes and experience also provide a huge challenge for China. This calls for an integrative opportunistic strategy that creates enabling conditions for linking the SCI investment agenda with those from other sectors. These transformations cannot be made overnight: completing the transformation process will typically take a life time of one generation. The progress in sustainable urban water management is also impacted by innovations in technologies as well as in management strategies. These technological innovations create fertile ground for businesses to adapt state-of-the-art developments from around the world and contextualize them into fit-for-purpose products. China is well-placed to play a leading role in this process in the coming decade.

Worldwide, an increase in flood damage is observed. Governments are looking for effective ways to protect lives, buildings, and infrastructure. At the same time, a large investment gap seems to exist—a big difference between what should necessarily be done to curb the increase in damage and what is actually being done. Decision-makers involved in climate adaptation are facing fundamental (so-called deep) uncertainties. In the course of time, the scientific community has developed a wide range of different approaches for dealing with these uncertainties. One of these approaches, adaptation pathways, is gaining traction as a way of framing and informing climate adaptation. But research shows that “very little work has been done to evaluate the current use of adaptation pathways and its utility to practitioners and decision makers” (Lin et al. 2017, p. 387). With this paper, the authors, as action researchers and practitioners involved in two of the world’s largest real-life applications of this approach in flood risk management, aim to contribute to filling in that gap. Analysis of the experience in the United Kingdom and the Netherlands in long-term planning in flood risk management shows that the adaptation pathways approach is effective in keeping decision processes going forward, to the final approval of a long-term plan, and helps increase awareness about uncertainties. It contributes to political support for keeping long-term options open and motivates decision-makers to modify their plans to better accommodate future conditions. When it comes to implementing the plans, there are still some major challenges, yet to be addressed, amongst others: the timely detection of tipping points in situations with large natural variability, the inclusion of measures that prepare for a switch to transformational strategies, and the retention of commitment of regional and local authorities, non government organizations, and the private sector, to climate adaptation as national policies move from blueprint planning to adaptive plans. In delivering this feedback, the authors hope to motivate the scientific community to take on these challenges.

Three different conceptual frameworks of resilience, including engineering, ecological and social–ecological have been presented and framed within the context of flood risk management. Engineering resilience has demonstrated its value in the design and operation of technological systems in general and in flood resilient technologies in particular. Although limited to the technical domain, it has broadened the objectives of flood resilient technologies and provided guidance in improving their effectiveness. Socio-ecological resilience is conceived as a broader system characteristic that involves the interaction between human and natural systems. It acknowledges that these systems change over time and that these interactions are of complex nature and associated with uncertainties. Building (socio-ecological) resilience in flood risk management strategies calls for an adaptive approach with short-term measures and a set of monitoring criteria for keeping track of developments that might require adaptation in the long-term (adaptation pathways) and thus built-in adaptive capacity as opposed to building engineering resilience which involves a static approach with a fixed time horizon a set of robust measures designed for specific future conditions or scenarios. The two case studies, from a developing and a developed country, indicate that the concepts of ecological and socio-ecological resilience provide guidance for building more resilient flood risk management systems resulting in an approach that embraces flood protection, prevention and preparedness. The case studies also reveal that the translation of resilience concepts into practice remains a challenge. One plausible explanation for this is our inability to arrive at a quantification of socio-ecological resilience taking into account the various attributes of the concept.This article is part of the theme issue ‘Urban flood resilience’.

To prevent floods from becoming disasters, social vulnerability must be integrated into flood risk management. We advocate that the welfare of different societal groups should be included by adding recovery capacity, impacts of beyond-design events, and distributional impacts. To prevent floods from becoming disasters, social vulnerability must be integrated into flood risk management. This Comment advocates that the welfare of different societal groups should be included by adding recovery capacity, impacts of beyond-design events, and distributional impacts.