Robust and climate-adapted blue-green solutions for stormwater management

In order to cope with climate change and increasing urbanization, green infrastructures for stormwater management are becoming key solutions. In Norway, the 3-step strategy is used. It consists in 1) managing day-to-day rains at the source based evapotranspiration and infiltration depending on local conditions, 2) dampen and delay  the larger rain events through local drainage, and 3) ensure safe diversion through defined floodways. The is a need to link different disciplines such as climatology, urban hydrology and risk quantification to increase understanding of how the steps in the 3-step strategy can be aligned with the operational implementations to provide robust and climate-adapted stormwater management in cities.

PhD candidate Vincent Pons has developed a new framework for designing blue-green solutions in alignment with the 3-step strategy. The framework proposes to move away from an event-based design to look at both long term continuous simulation and large datasets of extreme rain events. The goal is to quantify the retention performance for step 1, and evaluate the design limits in terms of detention through step 2. At the same time, you will receive information about when the solution(s) fails, which will provide useful information and guidance for designing of the floodways (step 3). Vincent also developed a new method based on statistical-temporal downscaling to be able to assess the future performance of the solution(s) using the same framework. Finally, Vincent has also studied the effect by scaling up from a single solution to many solutions within a neighbourhood/district.