Investigating the potential of real-time control (RTC) and blue-green infrastructure integration in Rotterdam’s Spangen neighborhood

Abstract

The Spangen neighborhood in Rotterdam West, the Netherlands, is highly vulnerable to pluvial flooding due to its low elevation, numerous impervious surfaces, and proximity to the Delfshavense Schie canal and a surrounding feeder canal. These factors contribute to high local surface runoff and strain on the local combined sewer system (CSS), leading to combined sewer overflows (CSOs) and local street fooding (“water op straat”). This study investigates the potential of integrating blue-green infrastructure (BGI) together with real-time control (RTC) to mitigate flood risk by reducing both the volume and frequency of CSOs and swale overflow events. A hydrological model, built utilizing 20 years of meteorological data with a 10-minute resolution from November 01, 2004 to October 01, 2024, simulated the hydrological effects of three progressively integrated bioswale configurations, a baseline scenario, and further modeled the effectiveness of RTC as valves outfitted at the base of the swale overflow tructure in preemptively releasing forecasted runoff over a 12-hour lead time. Results demonstrated that while the baseline scenario revealed 582.5 mm of CSO overflow over 188 events during the study period, when implemented, bioswales alone reduced net flow to the receiving water body by up to 95%, and RTC-enabled bioswales, in the most intensive configuration, could fully, pre-emptively remove stored swale volume to completely eliminate uncontrolled overflow. The 25% interception fraction performed best for Configuration 1, and 50% fraction performed best for Configurations 2 and 3, which all minimized the net flow out to the receiving water body, most efficiently integrating the existing CSS and proposed bioswales. Beyond mitigating flood risks, BGI offer co-benefits such as enhanced ecological connectivity, improved water quality, and urban livability, serving as a tool to provide Gemeente Rotterdam with a new possibility to achieve other sustainability goals, such as increasing green space access. This research demonstrates that the integration of RTC with BGI can serve as a scalable model for climate-resilient urban water management in Rotterdam, and worldwide.