Integrating Green and Gray : Creating Next Generation Infrastructure :: World Bank – World Resources Institute


Integrating Green and Gray : Creating Next Generation Infrastructure
World Bank – World Resources Institute
Author(s): Browder, Greg; Ozment, Suzanne; Rehberger Bescos, Irene; Gartner, Todd; Lange, Glenn-Marie
Published: 2019-03-21 :: 140 pages
English PDF (14.63MB)
A new generation of infrastructure projects that harness the power of nature can help achieve development goals, including water security and climate resilience. In this report from the World Bank and World Resources Institute, both organizations are calling for green infrastructure, such as mangroves and wetlands, to play a bigger role in traditional infrastructure planning. Integrating nature into mainstream infrastructure systems can produce lower cost and more resilient services. This report guides developing country service providers and their partners on how to seize this opportunity. It reviews approaches and examples of how to integrate green infrastructure into mainstream project appraisal processes and investments.

:: Traditional infrastructure systems worldwide rely on built solutions to support the smooth and safe
functioning of societies. In the face of multiplying environmental threats, this approach alone can no
longer provide the climate resiliency and level of services required in the 21st century.

:: Natural systems such as forests, floodplains, and soils can contribute to clean, reliable water supply
and protect against floods and drought. In many circumstances, combining this “green infrastructure”
with traditional “gray infrastructure,” such as dams, levees, reservoirs, treatment systems, and pipes, can provide next generation solutions that enhance system performance and better protect communities.

:: Service providers such as water utilities, flood management agencies, irrigation agencies, and
hydropower companies can deliver more cost-effective and resilient services by integrating green
infrastructure into their plans. However, to guide its appropriate use in mainstream infrastructure programs, green infrastructure must be as rigorously evaluated and carefully designed as gray projects.

:: This report offers service providers a framework to evaluate green infrastructure from a technical,
environmental, social, and economic perspective, and to assess key enabling conditions, with illustrative examples.

:: It also provides guidance for policymakers and development partners, who must set the incentives and enabling conditions to mainstream solutions that unite green and gray infrastructure.


Press Release : 21 March 2019
Green and Gray Infrastructure More Powerful When They Work Together, Says New Report
Integrating Green and Gray – Creating Next Generation Infrastructure shows how weaving the power of ‘green’ natural systems, including flood plains and forests, into ‘gray’ traditional infrastructure systems can lower cost and increase resilience.

“If we help nature then nature can help us – that’s the message of this report,” said Interim President of the World Bank Group Kristalina Georgieva. “Measures like replanting wetlands can shield cities from storms and flooding, and protecting forests improves watersheds. Infrastructure should make use of plants and nature to boost resilience and create a more livable environment.”

The report showcases World Bank projects where green infrastructure is already being deployed. For example, in Brazil, forests filter biological impurities to protect water sources and reduce the need for expensive water treatment plants upgrades. In Vietnam, mangroves are used as a first line of defense against typhoons and sea surges, helping to reduce investments in expensive man-made sea dikes. And in Somalia, natural river sediments are trapped behind dams, helping to recharge local aquifers, thus eliminating the need for deep and expensive groundwater pumps.

The report illustrates how emerging technology such as earth-based observations and advanced modelling make it cheaper and easier to design and assess the performance of green infrastructure. It also lays out a new framework for practitioners and service providers to integrate green infrastructure into gray, including technical, environmental, social, and economic dimensions.

The report finds that integrating green and gray infrastructure can help deliver a “triple-win” with benefits for the economy, communities, and the environment…