These cities are already improving their infrastructure. But most of the focus remains on big engineering solutions (like flood walls and embankments) rather than a more holistic plans that would involve every level of society. As we have recently argued in our research, these cities must instead become truly “resilient societies” – before it is too late.

BLUE-GREEN INFRASTRUCTURE

There have been some attempts to move beyond a simple focus on engineering. For instance, one approach is to put in place so-called blue-green infrastructure, which uses the planning system to integrate rivers, canals, or wetlands (the blue) with trees, lawns, parks, or forests (the green). This can involve anything from small-scale “rain gardens” that allow water to drain naturally through soil, to much larger-scale artificial wetlands or ponds.

For instance, the port city of Ningbo, where one of us is based, transformed a 3km strip of brownfield into an eco-corridor and public park.

Shanghai has also turned its new “Land of Starry Sky” park (so named because it neighbors an astronomy museum) into a sponge facility, using permeable materials to absorb rainwater. The Chinese government recognized sponge cities can achieve more sustainability goals than solely relying on traditional engineering structures.

WE NEED RESILIENT CITIES

In our new research, we studied existing practices and identified a lack of adequate engagement with key stakeholders (such as local industry, small businesses, and communities) as the main problem. Engagement with stakeholders such as these is key to improving outcomes of blue-green infrastructure, and such engagement is easier than ever thanks to the widespread use of mobile and digital technologies. Ideally, climate resilient infrastructures should be considered a co-production of all these various groups.

For example, sponge cities have successfully integrated nature-based solutions with traditional engineering. Yet these cities often struggle to get everyone involved in proactively thinking about the risk of floods. We argue that the key to resilient flood management lies in getting the whole society engaged in preventing floods where possible, in adapting to their worst impacts and in ensuring a timely return to the pre-disaster state.

The absence of this social engagement exacerbates flood impacts especially in poorer and more vulnerable parts of the world. Our research stresses that any truly resilient city must have a flood management plan that integrates natural, engineered and social systems.