Green infrastructure is starting to mean different things to different people, said David Rouse, ASLA, a landscape architect and planner at Wallace, Roberts & Todd (WRT) during a session at the American Planning Association (APA) conference in Chicago. Rouse was there with Theresa Schwarz, Kent State Cleveland Urban Design Collaborative; Karen Walz, Strategic Community Solutions; and Ignacio Bunster-Ossa, FASLA, a landscape architect with WRT, who together co-authored a new book published by APA called Green Infrastructure: A Landscape Approach.
There are really two definitions of green infrastructure. One is an inter-connected network of green open spaces that provide a range of ecosystem services — from clean air and water to wildlife habitat and carbon sinks. The other is a more limited one promoted by the E.P.A.: small-scale green systems designed to be urban stormwater management infrastructure. In either definition, green infrastructure is about bringing together “natural and built environments” and using the “landscape as infrastructure,” said Rouse.
Beyond getting the definitions right, Bunster-Ossa said the purpose of the book was to make sure these important concepts weren’t mired in the ugly debates about landscape urbanism, which has become a loaded term for many new urbanists, smart growth advocates, and others promoting increased density. He said “there’s been too much fighting over that, so here’s a way to clearly define the benefits of these systems.”
For Rouse, green infrastructure can improve our health, particularly our mental health, by making places more green and walkable. Think of green spaces and how they are much better to walk through than treeless, concrete environments. Those greener spaces are also safer. As research is proving, greener spaces have less crime, particularly domestic violence. The presence of greenery can also boost children’s education performance as well as the cognitive ability of adults.
Given the multiple benefits of green infrastructure, it should be understood using terms like “multifunctionality, connectivity, habitability, resiliency, and identity,” along with “return on investment.” Rouse said these principles can be applied at green infrastructure projects at all scales.
Here are some lessons from the experts who’ve tried to apply green infrastructure at the landscape scale (these are also case studies in the book):
Put the Green Before Grey
Schwarz said “cities in transition” sounds better than a “shrinking” city, which is what Cleveland is. Cleveland has lost half of its population so it has surplus real estate. Vacancies are everywhere “but not aggregated.” In total, Cleveland has about 20,000 vacant homes over 3,000 acres of land.
So the city has created a new plan to redevelop in strategic places, keeping density in key areas while using cleared areas for green infrastructure to handle stormwater. The city is now demolishing huge chunks of the vacant homes, adding about 120 acres of cleared land every year.
Much of these cleared surfaces can be used for infiltration, but a plan was first needed first target existing watersheds and understand the soils. Schwarz said soil surveys of Cleveland found there many types of soils, but really only the sandiest ones allow for infiltration. Other soils may appear fine but were actually heavily contaminated from industrial use.
In many cases, finding the original watershed was also tricky: So many indigenous waterways were buried underground to make way for some earlier development. Schwarz’s team worked on identifying the “headways” of rivers and culverted streams, seeing them as the best places to bring back vegetation to deal with stormwater. At the neighborhood scale, riparian corridors are planned as well.
While all of this sounds great, the E.P.A. was really forcing Cleveland to do all this work. The aging combined stormwater and sewer system in the city means there are 126 combined sewer overflows (CSOs) into Lake Erie each year, dumping some 4.5 billion gallons of runoff and waste. The E.P.A. is forcing the city to spend $3 billion as part of a “consent decree” to address the issue. While her group is pushing forward with green infrastructure mapping, Schwarz said, unfortunately, much of this money is going towards hard grey infrastructure — “seven really big deep tunnels” — with only some $42 million available for green infrastructure. “This is expected to handle around 44 million gallons of runoff, not much out of 4.5 billion gallons.”
Schwarz said the green infrastructure would have been more effective if “the green was designed first, before the grey.” Still, her group and others are pushing the city to make the best of it and add green infrastructure along the strategic reinvestment zones, the highly-trafficked corridors, making those “sustainable patterns of development” even more attractive. She’s also making sure the city applies a “green infrastructure decision making framework,” so that when land becomes vacant it can quickly be evaluated by the city to determine if it’s best used for redevelopment or green infrastructure.
Look for the Long-term and Large-scale
According to Walz, the North Texas region, which encompasses Dallas and a number of other cities, is the 4th largest metropolitan region in the U.S. The area has a “strong economy” so there’s been rapid population growth. In 2000, the area had 5.3 million. Double that is expected by 2050. Within the region, efforts are underway to let the Trinity River meander through Dallas, taking it out of its levees, and preserve and expand green infrastructure. Broader visions, including Vision North Texas, Trinity River Common Vision, and others, aim to “create regional thinking, but local implementation” on green infrastructure.
To make the local implementation part happen, Walz worked with the local community using “green printing” and integrated stormwater management (ISWM) approaches, a kind of mapping process to gauge what the local values are, where green infrastructure opportunities are, and find the places where the values and opportunities co-join to create “triple bottom line benefits.”
For Walz, the lessons learned were that “landscape shapes development. This is a concept we used to understand.” She said her public process has helped people understand how to “combine a landscape analysis with local residents’ values, so that in the future the landscape can actually shape development patterns.” Through public input, the community could find out which areas it values the most and preserve. She said those watersheds and natural areas that the community deemed to have the highest value were also “the same assets that will them create a more sustainable and distinctive community.”
She added that planning at the regional scale creates more benefits for communities. “Green landscapes, natural systems don’t end at the city limits.” Forming those partnerships that cross city lines helps create the broader regional vision.
To craft that vision, multiple disciplines should be be involved. “While that brings challenges, there are also great rewards.”
Lastly, Walz said “look for the long-term and large-scale” opportunities. (It’s also clear that the lingo or terminology around green infrastructure may get in the way when trying to reach a community. Walz said “these green infrastructure approaches are valuable regardless of what they’re called.”)
Create Local Connections to Green Infrastructure
WRT is working on a massive project in Louisville, Kentucky — the Parklands of Floyd’s Fork. At the edge of the city, four parks, each named for a tributary to the waterway, will protect some 3,700 acres along a prime watershed, helping to create a green edge around a city sprawling out.
Bunster-Ossa said he approached the green infrastructure aspects of the project using the “principle of connectivity.” Also important were creating a real local identity for the green infrastructure systems. While the proposed designs offer lots of ecosystem service benefits (approximately $18 million worth, said Bunster-Ossa), it’s really about creating a place people that people can connect to.
Bunster-Ossa introduced another example WRT worked on with Margie Ruddick, ASLA, this time in a highly urban environment: the new 1.5-acre, $45 million Queens Plaza park, which uses plants while also protecting pedestrians in a dangerous intersection, “making green infrastructure visible.” Sidewalks were dug up to form barriers that prevent pedestrians from jaywalking, while rain gardens provide a respite from the urban jungle. The park is viewed as such a useful amenity that Jet Blue recently put its new headquarters a few blocks away.
Bunster-Ossa said nearby buildings weren’t excluded from discussion about the new park. With green infrastructure, you can “flow from the interior of buildings to parks to wateryways, all the way to the region.” Now there’s landscape-scale thinking.
Image credit: (1) APA Books, (2) Demolishing vacant buildings in East Cleveland / Cuyahoga Land Bank, (3) Vacant land in Cleveland / Urban Current, (4) Trinity River / Trinity River Project, (5-6) Floyd’s Fork / WRT, (7) Queens Plaza / Margie Ruddick, WRT.