Impact of land use and rainfall change on runoff and flood resilience of an urban environment: a case study of Chennai City, India

Abstract

Urban flooding can differ significantly from rural flooding due to the influence of rapidly changing land use and rainfall patterns on runoff in urban areas. Consequently, understanding and managing urban flooding necessitate a comprehensive grasp of these influential factors. This study focuses on assessing the impact of land use and rainfall changes on runoff and flood resilience in urban areas of Chennai, India, utilizing the InVEST-UFRM model. The research includes an evaluation of flood risk and potential damage to building infrastructure, examining 14 sub-basins within the study area with diverse land use and rainfall depths for 2015, 2020, and 2025. Observed rainfall and land use data were employed for 2015 and 2020, while future rainfall data relied on Global Circulation Models (GCMs) of the Coupled Model Inter-comparison Project-6 (CMIP6) outputs and QGIS MOLUSCE plugin predicted land use for 2025. The study identified that the change in land use had a more significant impact on runoff than the temporal change in rainfall amount. Notably, the reduction of water bodies in the study area emerged as a major contributing factor to excessive runoff. The estimated maximum potential damage to built infrastructure in the study area reached approximately 10 billion USD. This research provides valuable insights into urban flood resilience and the impact of land use and rainfall changes and proposes effective measures for flood adaptation and mitigation. The study findings can serve as essential tools for urban planners in an effective management of urban floods in similar regions as investigated here.