A scenario-based analysis of wetlands as nature-based solutions for flood risk mitigation using the TELEMAC-2D model

作者：Kirk B. Enu, Fabian Merk, Hongren Su, Manuel Rauch, Aude Zingraff‐Hamed, Karl Broich, Kristian Förster, Stephan Pauleit, Markus Disse · 发表于：Nature-Based Solutions · 年份：2025 · DOI：10.1016/j.nbsj.2025.100236 · 被引用次数：4 · 研究领域：Flood Risk Assessment and Management、Water resources management and optimization、Land Use and Ecosystem Services

Urban flooding is an escalating threat in rapidly urbanising regions, particularly in sub-Saharan Africa (SSA), where unregulated expansion and climate change intensify risks. Nature-based Solutions (NbS) are increasingly recognised as sustainable and cost-effective, yet empirical evidence to support their strategic planning, especially through high-resolution modelling in data-scarce settings, remains limited. This study presents one of the first integrated applications of spectral indices and TELEMAC-2D hydrodynamic modelling to assess NbS effectiveness in a rapidly urbanising SSA city, the Greater Kumasi Metropolitan Area (GKMA) in Ghana. Focusing on the Aboabo catchment, we analysed wetland ecosystem loss (1986–2023) and evaluated the impact of NbS interventions (floodplain restoration and wetland creation) on flood dynamics. Specifically, we assessed the flood reduction potential of different implementation scenarios and how these scenarios affect the timing and intensity of peak flows under varying storm conditions. Results show that wetland cover declined (59 %) while built-up areas expanded (134 %), leading to reduced cumulative discharge and more intense, shorter-duration floods. The combined scenario (floodplain restoration and wetland creation) achieved consistent peak flow reductions (16–19 %) in prolonged storms, while the ambitious_restoration scenario (restoring the full floodplain network) performed best (24 %) in short-duration events. In contrast, the landsc...