In many camps, the philosophy around infrastructure development has changed. How we conceive of the built environment is increasingly taking into consideration the natural environment for more holistic, sustainable, long-term solutions.
One area that’s particularly exciting is how we can design new water infrastructure that not only meets the needs of society, but also enhances nature. By incorporating vegetation, soils and natural processes into our engineering solutions, formerly gray infrastructure approaches are turning green. This green infrastructure (GI) approach helps connect human activities to ecosystem services — such as water availability, flood mitigation and erosion control — that support our lives.
In a new guide prepared for the United States Agency for International Development (USAID), we summarize a wide range of GI applications and their benefits, offering an expanded scope in terms of application and scale. From site specific technologies such as rain gardens and green roofs, to regional planning and engineering strategies that target conservation of natural landscapes and watersheds, GI can fit a variety of settings and needs.
Additionally, GI approaches can be linked with existing and planned gray infrastructure networks to create more sustainable built systems that minimize environmental impact. In terms of disaster resilience, resulting win-win outcomes can enhance community resilience where GI offers water retention and groundwater recharge, flood mitigation, erosion control, shoreline stabilization, improved water quality and energy conservation.
GI has traditionally addressed the benefits to both people and nature through the management of stormwater runoff. However, we have found that GI approaches are increasingly being applied more broadly to provide a range of solutions in a variety of settings and scales beyond that of urban stormwater management. This understanding offered a dynamic backdrop of possibilities during last month’s annual World Water Week in Stockholm, the theme of which was “water, ecosystems and human development.”
Let’s look at some of these different applications and the benefits they provide:
In terms of scale, regional approaches often integrate multiple GI approaches to meet watershed-wide goals and objectives for people and nature. For example, on the USAID-funded PARA-Agua project in Peru, AECOM facilitated watershed planning meetings with civil engineers, infrastructure managers, conservationists, and representatives of watershed authorities in order to evaluate improved engineering design options for water management infrastructure as a whole. Infrastructure systems considered for a “green upgrade” included reservoirs for water storage, irrigation systems and drinking water supply.
The result of this effort was that stakeholders were able to define and work toward a shared vision to improve infrastructure function through better water conservation technologies, and to link infrastructure with groundwater recharge areas in order to safeguard the water resources on which these infrastructure assets depend.
In terms of setting, urban stormwater runoff systems offer benefits beyond their immediate context of capturing and channeling floodwaters away from densely populated areas. For example, efforts are now employed to channel floodwaters to rain gardens and natural landscapes to enhance the quality of the urban environment. Rural GI can focus on engineering applications to enhance crop productivity by increasing the efficiency of water use, increasing water infiltration and groundwater recharge, and reducing top soil loss from wind and water erosion. And of course, in both urban and rural landscapes, incorporating vegetation and improved flora management into built and natural systems can enhance resiliency of human settlements by reducing flood risks.
The opportunities to maximize win-win solutions with GI are seemingly boundless as we learn daily about applications in new contexts and settings. This is inspiring for practitioners and managers alike, with the water-human-ecosystem nexus one of the primary topics of conversation at the World Water Week event.
By integrating the needs of natural systems with those of the built environment in a range of settings, GI protects natural resources and ecosystem functions from varied impacts of human activities.