Assessing low-impact development strategies using synthetic rainfall under climate change across different urbanization densities

Urban flooding, exacerbated by climate change and rapid urbanization, presents major global challenges. This study assesses flood dynamics and proposes management strategies for Hyderabad, India, focusing on urbanization density zones XII, IV, and V. Urban flood modeling evaluates the combined impacts of climate and land use/land cover (LULC) changes from 2020 to 2075, covering both present and future scenarios. The modeling uses the PCSWMM framework, integrating synthetic rainfall data derived from Hyderabad's Intensity-Duration-Frequency (IDF) curve for 2-, 5-, and 10-year return periods, and rainfall generated through the Markov chain method for 1- to 10-day durations. These datasets support both flood modeling and the development of management strategies. Low-impact development (LID) strategies are implemented based on critical catchment prioritization and available open spaces. PCSWMM results indicate significant reductions of 8-16.41% and 3.57-12.4% in maximum flow at outlets following LID implementation during extreme 1-10-day events in zones IV & V and XII, respectively. Additional reductions of 0.59-5.58% and 0.24-0.45% are noted for synthetic rainfall events with 2-, 5-, and 10-year return periods. The study recommends adopting multiple LID types to effectively mitigate flood damage and highlights the importance of enhancing LID infrastructure for improved flood resilience.