Green Stormwater Infrastructures: A Sustainable Strategy for Mitigating the Ultra-Urban Impacts of Megacity Dhaka

Abstract

The megacity of Dhaka, Bangladesh, is becoming increasingly exposed to the negative consequences of rapid and uncontrolled development, such as chronic waterlogging, frequent flooding, and the intensification of the urban heat island effect. The expansion of impermeable surfaces, as well as the encroachment on natural drainage systems such as canals and wetlands, all contribute significantly to these difficulties. Traditional “gray” infrastructure has proven insufficient to accommodate the volume and complexity of stormwater management in this ultra-urban environment. This review paper investigates the potential of Green Stormwater Infrastructure (GSI) as a sustainable and resilient alternative. Using a variety of global and regional studies, the article assesses the suitability and effectiveness of GSI practices—such as rain gardens, tree trenches, permeable pavements, bioswales, and green roofs in densely populated areas like Dhaka. The review focuses on GSI’s multifunctional benefits, such as improved stormwater regulation, water quality, air quality, urban heat mitigation, and the return on investment for restoration of important ecosystem services. The findings highlight the importance of incorporating GSI into Dhaka’s urban planning framework to promote long-term environmental sustainability and urban resilience.