Triple Bottom Line Benefits of Implementing Green Infrastructure for Runoff Management

Abstract

Urbanization and climate change are intensifying challenges in urban water management, including increased flood risks, reduced water quality, sewer overflows, and exacerbated urban heat island effects. Green Infrastructure (GI) provides a sustainable alternative to traditional gray infrastructure by managing stormwater on-site through natural processes, which mitigates surface runoff and improves environmental conditions. This study evaluates the effectiveness of GI in a 12.7-hectare cluster in Dubai Land, UAE, an area comprising residential zones, open spaces, and local roads. Two scenarios were modeled: a traditional gray infrastructure system with pipes, manholes, and gullies and a GI system integrating Green Roofs (GR), Rain Gardens (RG), Pervious Pavements (PP), and grassed side ditches. The study shows that GI reduces runoff by 79% with 50% GR coverage and pervious asphalt for roads and by 68% with 25% GR coverage compared to conventional concrete and asphalt surfaces. Specific metrics-including runoff volume reduction, cost efficiency, groundwater recharge, and urban cooling potential-were used to assess GI’s performance. Economically, GI reduces the need for extensive gray infrastructure, with 60% GR coverage achieving costs similar to conventional systems but with improved runoff reduction. GI implementations covering 50% and 30% of roof areas yield 10% and 37% cost savings, respectively. Environmentally, GI lowers flood risks, enhances groundwater recharge, and improves water quality. Socially, GI fosters better air quality, recreational spaces, climate resilience, and public health. This study underscores the value of incorporating these triple bottom line (TBL) benefits into urban planning, illustrating GI’s role in immediate stormwater management and the long-term sustainability of rapidly urbanizing regions.