The Concept of Workable Rainwater Harvesting Drainage System in Reducing Flash Flood Risk in Historical City

This study investigates how rainwater harvesting drainage systems can help mitigate flash flood risks in historic urban areas facing increasing threats from rapid development and climate change. Historic cities often have extensive impermeable surfaces, such as roads and buildings, preventing water from soaking into the ground. This leads to greater surface runoff during heavy rainfall, heightening the risk of flash floods. The research evaluates the effectiveness of existing rainwater harvesting drainage systems by combining quantitative data analysis and qualitative case studies. Field data are analysed using the Statistical Package for the Social Sciences (SPSS) to ensure robust results. Key features of successful systems include their capacity to capture, store, and redirect excess rainwater, thus reducing surface runoff volume and speed. Early findings show that rainwater harvesting drainage systems effectively reduce flash flood risk by promoting water infiltration and conserving rainwater for reuse. These benefits align with sustainable urban development goals. Additionally, enhancing drainage infrastructure can protect public buildings, homes, and critical services from flood damage, offering economic and social advantages. The study concludes by recommending improvements in drainage system design, legal enforcement, and urban planning practices. It emphasises the importance of context-appropriate solutions and regulatory compliance to building flood-resilient historic cities. Ultimately, these insights are intended to guide urban planners, policymakers, and developers in making informed decisions for safeguarding heritage cities from urban flooding.