Climate Adaptation of Urban Stormwater Systems

Precipitation is intrinsically associated with high uncertainty, which is exacerbated exponentially over time, especially concerning climate change. However, the current design practice in urban drainage infrastructure remains firmly bound to deterministic assumptions regarding the design load. This approach is too simplified—focusing only on the return period of the design event—and ignores the complexity of drainage systems and the potential changes in catchment hydrology and the at-risk valuable assets within. Therefore, the current design approach is inherently an unsustainable practice that cannot deal with extreme uncertainties associated with urban drainage and flood resilience in changing climate and society. In this presentation, we will examine the current deterministic design practice and encourage a collective discussion on the need for a paradigm-shift in the engineering of urban drainage infrastructure. In a changing society and an uncertain climate, climate adaptation should be a continuous work that needs to be integrated into societal development and become part of traditional management and maintenance work. The ultimate objective is to enable problem-owners, engineers, and decision-makers to quickly and continuously see where the problem is the biggest and which measures should be implemented where and when. In the shadow of economic difficulties and the limitation of resources, this shall be done with regards to the assessed risk landscape for our cities through a risk-based design.