Author(s): Fahad Ahmed; Lars Backhaus; Ho Huu Loc; Mukand Singh Babel; Juergen Stamm

Linked Author(s):

Keywords: 3-D digital city models; Nature-Based Solutions; Stormwater Management; Climate Change; Evidence-based decision-making; Udonthani City

Abstract: Urbanization disrupts the water cycle by replacing natural vegetation with impermeable surfaces that hinder rainfall infiltration into the ground. Urban drainage systems often overlook how changing land use contributes to urban floods during rainfall. Climate change influences both the frequency and intensity of extreme precipitation events and intensifies urban drainage pressure. "Green infrastructure" reduces runoff but cannot fully replace "grey infrastructure" due to safety concerns in extreme events. Also, ecological factors necessitate controlled construction scales for "grey infrastructure. " Hence, coupling "grey-green infrastructures” is crucial for optimal urban runoff control and enhancing water security. Assessing integrated flood management before construction is challenging, but numerical modeling and computational technologies provide a sustainable strategy. Digital city models offer streamlined management, communication, and consensus-building, efficiently showcasing the crucial role of NBS in flood mitigation to public authorities, stakeholders, and citizens. For Udonthani (Thailand), a flood-prone city, a numerical approach incorporating NBS is vital for evaluating the effectiveness of NBS in adapting to climate change. In this study, a 1-D SWMM5 model was built and evaluated with various standalone NBS and combinations of NBS measures. The model, developed with the GisToSWMM5 tool, was calibrated and validated, and NBS performance was evaluated under future climate projections from the CMIP6, with two shared socioeconomic pathway scenarios (SSP2-4.5 and SSP5-8.5). Additionally, a semantic 3-D digital city model, incorporating urban infrastructure and drainage networks, was developed. Various simulations, including standalone and combined NBS measures integrated with grey infrastructure, were conducted under two climate change scenarios. The integration of "grey-green infrastructures" showed promising outcomes in enhancing urban runoff control. The study introduces a digital web application using free and open-source software and open data to raise NBS awareness in urban stormwater management under climate change. This enhances evidence-based decision-making and streamlines global urban planning for flood-prone areas.

DOI: https://doi.org/10.3850/iahr-hic2483430201-1

Year: 2024