Strategic Assessment of Urban Flood Risk and LID Mitigation under Climate Change: A Case Study of the Beitou–Shilin Technology Park

This study evaluates the hydrologic resilience of the Beitou–Shilin Technology Park (BSTP), a high-density newly developed district in Taipei, under intensified extreme rainfall induced by climate change. To support climate-adaptive urban water management, an integrated modeling framework combining urban drainage simulation and future climate projections was established.A detailed urban drainage model was developed using EPA SWMM to characterize the drainage system of the study area. Subcatchment geometries were delineated through QGIS-based spatial analysis, while infiltration parameters were assigned based on land-use types and vegetation coverage. This modeling framework provides a physically-based representation of surface runoff generation and urban flood response.To address climate uncertainty, future rainfall data were generated using the MultiWG stochastic weather generator. The projection process incorporated five Global Climate Models (GCMs) under three Shared Socioeconomic Pathway scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5). After completing data preprocessing, the daily synthetic rainfall series were temporally downscaled to an hourly resolution to enable continuous hydrologic simulations within the SWMM framework.Finally, a systematic sensitivity analysis of Low Impact Development (LID) strategies was conducted. Incremental implementation levels ranging from 0% to 100%, at 20% intervals, were simulated to quantify their effectiveness in reducing peak discharge and mitigating urban flood risk under extreme rainfall conditions. The results reveal a clear nonlinear relationship between LID implementation scale and runoff reduction efficiency. These findings provide quantitative insights for optimizing LID configurations in compact urban developments and support long-term, ESG-oriented urban infrastructure planning.