Author(s): Maele Belmont; Agnes Jourda Martinez; Luca Rossi; Dominique Zurcher; Giovanni De Cesare
Linked Author(s):
Keywords: Sponge City Urban Floods Surface Runoff Stepped Bio-Retention Cell Sloped Street Network Numerical Simulation Infiltration Blue-Green Infrastructure Low Impact Development
Abstract: In urban areas, land-use change and soil impermeabilization lead to significantly increased stormwater runoff, particularly challenging in cities with steep topography. This study investigates the implementation of the "Sponge City" concept in Lausanne, Switzerland, where an average slope of 9% challenges traditional integrated stormwater management approaches. The research develops a methodology to evaluate the hydrologic performance of a blue-green infrastructure (BGI) solution adapted for sloped terrain: stepped bio-retention cells. Using the Storm Water Management Model (SWMM), the study first analyzes the BGI at the control scale, examining its performance under various slopes (2%, 5%, 10%), capture ratios (5:1, 10:1, 15:1), for various rainfall scenarios. The analysis then scales up to assess its effectiveness at the neighborhood level through a coupled 1D-2D model, using a neighborhood selected for its representative topography and urban runoff flooding susceptibility. This research addresses the current knowledge gap in modeling BGI in stepped configurations and aims to provide insights for implementing sponge city practices in challenging topographic conditions.
Year: 2025