Quantifying urban catchment scale hydrological resilience to assess green-gray infrastructure application effects

Background/Question/Methods

The existing methods for mitigating urban flooding have focused on the volume expansion of sewerage systems, however, these measures alone are expensive and primarily aimed at water treatment, making them an unsustainable solution to unpredictable rainfall. Thus, strategies have been proposed and applied over the past decade to control runoff and delayed peak flow by restoring natural hydrologic circulation and maximizing infiltration and retention capacities at the source. In this study, using the green infrastructure (GI) concept, a model simulation was conducted to quantify the effects of GI on flood events by changes in different techniques, flood events, and urban drainage system (UDS) conditions.

Results/Conclusions

According to the results, for rainfall events with long durations, the effect of the adaptation practice was better than those with short durations and high-intensity. Adaptation practice also lowered peak flooding in the first two–fifths of the flood time. Assuming that the GI adaptation practice is applied to the study site where UDS improvement has been made, an effect similar to that of UDS improvement was shown. The results of this study are significant as they improve model accuracy through parameter optimization and model correction considering both past and current time points, and quantify the potential effect of GI technology based on flood ideas of various characteristics.