Green infrastructure is a strategy that, effectively applied, elevates parks to a more central role in our communities as part of our vital civic infrastructure. This article merges the two typically cited but different definitions of green infrastructure: a regional land protection strategy (such as greenways, conservation easements and floodplain protection), and a site-based set of technical tools (such as rain gardens and bioswales). This range of actions spans the spectrum from state, county and municipal scale, to construction of specific water quality enhancement projects at a site scale.
Application on a Range of Scales
Green infrastructure ranges from natural land preservation measured in square miles, and county and municipal efforts measured in acres, to the design of specific stormwater management bioengineering techniques measured in feet and inches. These green infrastructure scales apply across public and private lands, and in other city departments, notably streets and public works. In terms of park and recreation applications, green infrastructure applies to park systems, individual parks and specific projects within parks. Knowing the appropriate scale and strategies is central to devising the best way to apply and manage green infrastructure. Integrating the strategies across scales leverages the effects of green infrastructure to greater advantage and help to systematize its planning and management. For example, Maryland’s statewide green infrastructure planning policy requires each county to prepare a combined Land Preservation, Parks and Recreation Plan. Although there is presently no national plan, efforts are being made by Esri, a geographic information systems company, to develop one.
Water Is the Driving Force
Affected by climate change, water is an increasingly important issue across the nation — whether too much, too little or the quality of the water itself. Water quality protection is driven by compliance with the federal Clean Water Act which addresses the overall quality of our waterways and water supply. Flood control is typically governed by the U.S. Army Corps, but both the Environmental Protection Agency and the Corps have adopted an increasing willingness to use green infrastructure to serve their missions. In the past, so-called grey infrastructure — engineering measures such as dams, levees and pipe systems — have been used to solve these problems. These measures, while necessary in many cases, do not always represent the best solutions, especially in areas of existing high population where such facilities are harder to implement. As they age, they also require major reinvestment to maintain or to replace them. Green infrastructure, by contrast, has evolved into a suite of low-impact techniques that are more adaptable, less capital intensive and often provide a wider range of benefits.
Re-Thinking Stormwater Runoff
Low-impact techniques — specific planning and design tools, such as conservation easements, green roofs and rain gardens and other bioengineering methods — are part of a paradigm shift in our attitude toward stormwater management in a world where stormwater is both overabundant and scarce, frequently in the same year. We cannot ignore the increasing impact of stormwater, and we cannot afford to “dispose” of stormwater by draining it off without making use of it. In this new way of thinking, our undeveloped lands along water courses in the low lying areas of our communities and also in the uplands will serve as sponges that absorb, filter and infiltrate water into the aquifers below. Such actions provide other benefits in addition to water quality and control, such as environmental value through increased and enhanced habitat, and social value provided by the simple presence of more — and more interesting — green space. Parks, themselves, are green infrastructure at a communitywide scale.
Many communities face the threat of flooding from heavy precipitation. Coastal cities also face sea level rise from climate change. Viewed simply as large-scale land conservation, green infrastructure can help soak up stormwater upstream from our communities, by preserving open space and high-value wetlands in floodplains and upland areas, and reduce the volume of runoff headed downstream. In downstream communities, green infrastructure can help buffer developed areas from flood impact and limit damage. Parks and open space in coastal communities can help mitigate the effects of sea level rise and storm flooding.
Improving Water Quality
Older cities face the challenge of aging stormwater and sanitary sewer systems that were built as combined systems in the late 19th and early 20th centuries. In many of these communities, federal Clean Water Act compliance involves both stormwater and sanitary sewage, which are sometimes mingled in combined sewers that overflow in major storms, dumping untreated sewage into waterways. Previous long-term control plans and wet weather plans were based solely on construction of separate systems of huge pipes to store overflow prior to treatment and release. Increasingly, cities are relying on incremental green rather than (or in addition to) grey infrastructure. A community’s park system represents one of the larger “sponges” that can be used to help reduce the flow of stormwater to sewers. For example, Philadelphia has granted approval for a long-term control plan that relies largely on green infrastructure. This is being undertaken with an exemplary partnership between the water utility, Philadelphia Water, and the city’s park and recreation department. Kansas City and Pittsburgh have been granted approval, and other cities such as Portland are strong examples of places where such approaches are being used.
Reducing the Impact of Drought
Western cities and, increasingly, midwestern and eastern cities face the impact of drought of some duration. Increasingly, parks are being used to capture and store or infiltrate rainwater when it does fall, helping to keep it local longer. For example, in Austin, Texas, the park and recreation department is partnering with the department of watersheds to restore Shoal Creek in Pease Park, part of a strategy to provide shallow infiltration depressions in lawn areas. These areas balance recreational use with a citywide flood control, water quality and conservation mission to preserve the aquifer that underlies the region.
The role of parks in helping to mitigate these major challenges provides an opportunity for a different source of funding for acquisition and green infrastructural improvements, chiefly through the water management entities in the community. Pressure to alleviate flooding or comply with a Clean Water Act consent decree requires expenditures on projects that might not otherwise happen. While not always directly benefiting recreation, green rather than gray infrastructure almost always increases habitat value and associated anthropocentric values of aesthetics and education. The use of parks to accommodate green infrastructure in a sensitive manner with due public process can provide a related community benefit of stormwater management while remaining true to a park mission.
Using green infrastructure requires breaking down departmental and jurisdictional silos. Planning for green infrastructure requires park departments to play a role in a larger community partnership that includes planning, streets, public works and water and sewer entities. This is an opportunity to establish an additional value of parks and to promote a central role in the discussion of community infrastructural investment. This is also an opportunity to envision the park system as part of a larger network of other public, quasi-public and protected private open space, an approach this author refers to as “parks without borders.”
Green infrastructure is not without the complexity of tradeoffs. Bioengineered facilities that can accommodate water and provide wildlife habitat also take up room in parks and therefore compete for space with traditional recreational use. There is a tradeoff and debate regarding the use of parks for recreation to accommodate additional stormwater, sometimes from off-site. To provide the best perspective on the opportunities and tradeoffs of green infrastructure in parks, the issue is most effectively addressed at the time of a community’s comprehensive planning, or at least in park system master planning. This allows broad community input and values to be brought to bear and helps ensure that funding necessary for capital construction and maintenance is external to the existing parks budget.
Green infrastructure is a combination of our parks and open space — our wetlands and forests, meadows and lawns, and bioengineered constructions such as green roofs, rain gardens, bio-infiltration swales, flow-through planters and the like. These measures are most effectively considered together and planned for in an integrated comprehensive master planning process, coordinated with a wide range of partners and associated funding sources. Green infrastructure is best planned for first at the comprehensive plan stage; then at the system-wide planning, individual park master planning and development stages; and in ongoing operations. It is a positive and proactive response to increasing environmental challenges to our communities that places parks at the center of the solution.
Eric Tamulonis is a Principal and Landscape Architect with WRT Design.
The American Society of Civil Engineering defines parks as a category of civic infrastructure in its national Infrastructure Report Card.
Rouse, David and Bunster-Ossa, Ignacio (2013). “A Landscape Approach to Green Infrastructure.” Planning Advisory Service Report #571. American Planning Association. (With case studies by the author)
Rouse, David and Younger, Leon (2014). “Integrating Parks & Recreation Master Plans and City Comprehensive Plans.” National Recreation and Park Association. Annual Conference Presentation.
Tamulonis, Eric and Neer, Charles (2015). “How Parks Can Guide Regional Development.” Sustainable City Network.
The Trust for Public Land’s Center for City Park Excellence convened a colloquium of subject matter experts, including the author at Harvard University in 2014 to explore the relationship between green infrastructure as stormwater management and park values. The proceedings will be published this year.