INTEGRATING GREEN AND GRAY: Creating Next Generation Infrastructure

INTEGRATING GREEN AND GRAY: Creating Next Generation Infrastructure


As a joint undertaking of the World Bank and World Resources Institute, this report highlights how the next generation infrastructure can integrate natural systems (green infrastructure) with traditional, built projects (gray infrastructure). By advocating the “putting nature to work” thinking, the report provides a guide to developing countries on how to incorporate natural capital to projects in order to increase the quality of the services and reduce the total costs. It also features case studies of successful projects on how natural systems contribute to infrastructure services ranging from water purification and storage to flood management.


With increasing threats from Climate Change, traditional infrastructure systems (gray infrastructure) can no longer provide climate resiliency. This report provides a framework to evaluate green infrastructure from 3 perspectives namely: technical and environmental; social; and economic.

From a technical and environmental perspective, green infrastructure can take advantage of the natural and regenerative capacity of natural systems which can increase the resiliency and generate a myriad of positive environmental impacts. It puts emphasis on the vital roles of watersheds, wetlands, mangrove forests, river floodplains, and agricultural soils in uniting green and gray infrastructure. In addition, green infrastructure also has an important social dimension since it empowers communities by having an active role in project operations. With multiple stakeholder support, the viability of the project is assured. Lastly, in terms of the economic aspect, integrating nature to mainstream infrastructure systems can be both low-cost and cost effective, and therefore generate monetary and non-market benefits.


Browder G, Ozment S, Bescos IRehberger, Gartner T, Lange G-M. Integrating Green and Gray: Creating Next Generation Infrastructure. World Resources Institute. 2019. doi:10.46830/wrirpt.18.00028.


  • World Bank Group, Washington DC, USA
  • World Resources Institute, Washington DC, USA