Module 3: Leaders and Lessons of Green Infrastructure in Practice

GI exists in all cities to some degree, depending upon factors such as level of investment, protection of existing natural areas, adherence to engineering and planning standards, cultural and traditional designs that are reflected in the infrastructure, and geographical citing of urban centres. In many cases GI success and the benefits ecosystem services provide can be attributed to greater investment from the public and private sector. However, there are many factors that contribute to GI implementation success that are not dependent on significant levels of monetary resources. This module explores how cities around the world have made the most of the resources available to them to reap the greatest benefit from their GI systems.

The new technical terminology used to define modern green infrastructure belies an important truth: green infrastructure systems are often reminiscent of old solutions to familiar problems. Green (i.e. made of living things) infrastructure was the foundation of every successful pre-industrial human society. As early as 5000 BC, human societies used natural systems to try to stabilize their environments to help support larger concentrations of people. The ancient Egyptians were dependent on large floodable landscapes and shaded irrigation systems to manage the ebb and flow of the Nile. In the 1100s, the Khmer empire used vegetated channels to create irrigation works that survive to this day at sites like Angkor Wat. In the 1600s, the Dutch created living dikes that held rising seas at bay and contributed to their rise as a global sea power. Ancient empires often collapsed when they could no longer maintain the green infrastructure systems that supported them (Diamond, 2005).

The Dutch continue to proficiently mitigate sea level rise by adapting their traditional infrastructure systems to solve new challenges. Dutch green infrastructure has roots in the founding of their nation. Levies, dikes, and canals have enabled Dutch society. Today the Dutch systems are informed by modern science and technology to optimise the strengths inherent in living systems: adaptability, expansion and/or contraction, and durability/resiliency. Only after extensive deforestation and infrastructure failures did the Netherlands realize the indispensability of street trees to the stability of their canals and adjacent building foundations. These lessons have been learned through trial and error; invaluable lessons to be learned, adapted to and applied in other jurisdictions.

Cities that succeed in implementing GI do so because they acknowledge and account for the benefits that GI provides which traditional infrastructure does not. When the additional benefits of green infrastructure are accounted for, the case for integrating GI makes sense. Cities in the Pacific Northwest such as Portland, Oregon, Seattle, Washington and Vancouver, British Columbia have begun to plan and account for green infrastructure benefits beyond stormwater management such as improved urban livability, healthier ecosystems and low carbon resilience. Accounting for these additional benefits has helped redirect municipal resources towards green infrastructure development.

While New York City is famous for its wealth, it is infamous for its lack of space and its dense, narrow boulevards. Motivated by the need to reduce combined sewer overflows, the streets of New York City have undergone a rapid greening by streamlining the design and approval process for roadside green infrastructure systems. New York City created a thorough manual of standard GI designs that could be replicated throughout the city at relatively low cost. By utilizing economies of scale, the New York City Department of Environment reduced the material and labour costs of GI implementation and managed to install thousands of roadside bioretention systems in less than five years.

In Ontario, major flooding in the 1950s led to the creation of Conservation Authorities charged with managing and protecting watersheds to help protect communities and preserve local ecology. The Conservation Authorities are organized by watershed and work in partnership with all levels of governments and local communities. Their mandate is to protect life and property from water-related hazards and develop and maintain programs to conserve natural resources. The Conservation Authorities have the power to set standards and guidelines for development proposals in their jurisdictions and provide resources to member municipalities on how and where to implement green infrastructure systems. Two conservation authorities in particular, the Toronto Region Conservation Authority and the Credit Valley Conservation Authority, have become national leaders in green infrastructure research and development.