Spatial–Temporal Assessment of Urban Flood Vulnerability Using GIS and AHP in Klang River Basin

Abstract

Urban flooding has become an increasingly critical issue in rapidly urbanising regions, particularly in low-lying areas within river basins. Taman Sri Muda, Shah Alam, Malaysia, located in the Klang River Basin, has experienced recurrent and severe flood events, exacerbated by intense rainfall, rising water levels, and extensive urban development. Although numerous studies have applied Geographic Information Systems (GIS) to flood risk mapping, most assessments remain spatially static and fail to capture how flood vulnerability evolves in response to both environmental and anthropogenic changes. This study aims to assess the spatial-temporal evolution of flood vulnerability in Taman Sri Muda across three periods: 2016, 2020, and 2024 by integrating multiple factors that influence floods.  A GIS-based multi-criteria decision analysis approach was employed, incorporating rainfall, water level, elevation, slope, and land use/land cover (LULC). The Analytic Hierarchy Process (AHP) was applied to determine the relative importance of each parameter, followed by a weighted overlay analysis to generate flood vulnerability maps for each period. The findings indicate a significant increase in flood risk between 2016 and 2020, primarily driven by extreme rainfall and urbanisation, with slight improvements observed by 2024 following flood mitigation measures. However, areas in the northern part of Taman Sri Muda remain consistently classified as high-risk due to low elevation and proximity to the Klang River. This study presents a comprehensive spatial-temporal framework for assessing urban flood vulnerability and offers practical insights to support evidence-based urban planning and flood risk management in flood-prone cities.