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Green Infrastructure Toolkit
Using Nature to Manage Stormwater in the Face of Changing Precipitation Patterns


Green Infrastructure Toolkit Launch
September 19, 2016
On September 14, the Georgetown Climate Center released an interactive toolkit that helps practitioners quickly find green infrastructure information, along with up-to-date, real-world examples. The Center also hosted...


Communication Strategies for Green Infrastructure

Communication and Engagement

Communications strategies focusing on both the public and on other government partners are vital to implementing successful green infrastructure programs.  Increased public awareness and satisfaction with green infrastructure projects can lead to increased support for further projects as well as potential opportunities for private property owners to install their own green infrastructure practices, such as rain gardens. Collaborating with partner agencies can increase the potential buy-in for green infrastructure practices throughout the local government, as well as to increase the potential funding streams and manpower for ongoing operations and maintenance. As the benefits of green infrastructure are available more quickly than the benefits for gray, effective communication strategies can relay that information to the public to build support. Several strategies exist to communicate the benefits of green infrastructure:

Source: Clean Waters, Healthy Families Coalition,

Presentations and Workshops: Holding presentations and workshops enables staff to meet individual members of the community and better understand and meet community needs. For example, New York City’s Department of Environmental Protection makes presentations to community boards and other civic and environmental organizations, in addition to elected officials and their staffs, about the city’s Green Infrastructure Program.  Likewise, as part of its 10,000 Rain Gardens Program, Kansas City sponsored “how-to workshops” for private landscaping businesses and municipal employees that explained the initiative, rain gardens, and water quality concerns.  These workshops not only raised awareness but trained contractors and city employees in installation and maintenance techniques.

Media Campaigns: Kansas City engaged in an extensive media campaign involving interviews on television and the radio, as well as advertisements and articles in local newspapers.  These media campaigns reached an estimated three million people in 2007.  In 2013, New York City’s Department of Environmental Protection created an educational video on the Green Infrastructure Program, which described some of the environmental challenges caused by combined sewer overflows as well as some green infrastructure solutions such as green roofs, rain gardens, and permeable pavers. 

Websites: In 2013, New York City’s Department of Environmental Protection launched a new website that provides information on the City’s Green Infrastructure Program, including the most common types of green infrastructure practices as well as a map of priority areas. Community members can use the site to see if their neighborhood will receive green infrastructure installations and to better understand the practices. Kansas City’s 10,000 Rain Gardens initiative created a website offering residents and other audiences a clearinghouse of information pertaining to the program and to stormwater management more generally, and was receiving over 100,000 visits per year even after the main media campaign had ended.

Written Materials: Written materials such as brochures and surveys can be effective means of engaging the public and partner agencies about stormwater management practices and the municipality’s use of green infrastructure. For example, New York City’s Department of Environmental Protection developed a brochure that explains the siting and construction process for projects in the right-of-way, answers frequently asked questions, and describes the co-benefits of green infrastructure.  Similarly, Seattle Public Utilities (SPU) used parking surveys to better understand and meet the needs of the community for its Street Edge Alternatives Program. The surveys revealed community concerns about reductions in parking due to reductions in street width caused by the installation of green infrastructure projects.  SPU responded to this concern by installing occasional angled parking clustered along the street.

Inter-Agency PartnershipsCreating partnerships between agencies can help to implement green infrastructure practices both efficiently and effectively. By pooling the resources, expertise, and knowledge of different agencies, inter-agency partnerships can be crucial to successful pilot programs. These partnerships can exist to aid in any stage of the process, including planning, installation, maintenance, and monitoring. For example, in New York City, the Departments of Environmental Protection and Parks and Recreation have worked together to develop the Green Infrastructure Maintenance Program in order to allocate appropriate resources for the long-term maintenance of DEP’s green infrastructure projects.


Green Infrastructure Strategies and Techniques

Green infrastructure techniques for managing stormwater come in a variety of forms, and several techniques can often be combined in one project. All provide stormwater management and water quality benefits, but each provides a different variety of co-benefits (social or public health, for example) and different approaches are more appropriate based upon site-specific conditions. The following describes the range of green infrastructure interventions, how each works, the benefits each brings, and the type of sites where the technique can be deployed.   

Green roofs: Traditional roofs absorb sunlight and radiate heat into the surrounding air.1  Vegetation on green roofs shades the roof and cools the air through evapotranspiration.2  In this way, vegetation can cause a green roof to be 100 °F cooler than a traditional black roof,3  and these cooler roofs transfer less heat to the ambient air. Green roofs do not have as great a cooling effect on air temperatures as ground-level vegetation does, but they have the advantage of not taking up additional land and of keeping building occupants cooler.4  In addition to managing stormwater, green roofs help decrease energy use, improve air quality, and reduce heat.5  Green roofs, however, are not without challenges: They require greater structural support than cool roofs and are expensive to install.

Permeable pavements: Permeable pavements have spaces for air and water to pass through; the spaces allow water to infiltrate into the ground, reducing runoff. Asphalt and concrete can both be made porous by omitting the smaller aggregates that are usual components.6  More specialized forms of porous pavements include interlocking concrete pavers, in which water drains through the gaps between precast blocks, and grass or gravel pavers, in which fill materials are laid on top of a plastic grid.7  Permeable pavements also have cooling properties due to evaporation and reduced heat storage.8  Permeable pavements are appropriate for sidewalks, parking lots, alleys, and streets; some concerns about whether permeable pavements are appropriate for cold climates or high-traffic areas are being monitored and evaluated now in cities like Chicago and Washington, DC, with positive results to date.9 

Bioretention and Bioswales: Bioswales are a type of stormwater retention that use an open-channel shape and vegetation to slow runoff and filter pollutants, reducing strain on stormwater infrastructure and improving water quality.10  Often integrated into streetscapes or used to convey stormwater away from critical infrastructure, bioswales can also reduce the need for gray stormwater systems to be installed by capturing and storing some of the stormwater.11   Bioswales can also reduce temperatures, increase habitat for urban wildlife, and improve air quality. As an added benefit, they are often aesthetically pleasing and potentially increase property values.

Green Streets, Alleys, and Parking Lots: Green streets, alleys, and parking lots can combine all of the above strategies (except perhaps green roofs) into a coherent package. By combining the strategies, green streets can provide multiple benefits, including runoff and pollutant reduction, air quality improvement, and urban heat island mitigation.12  Local governments primarily install green streets in the public right-of-way, but green alleys and parking lots can be installed on both public and private land. For all three, a critical element can be to minimize pavement in the first place.

Rain Gardens: Rain gardens are small gardens that are designed to survive extremes in precipitation, and help retain or reduce stormwater runoff through infiltration or storage.13  The gardens are often small and placed strategically in areas where stormwater currently overwhelms drainage capacity. They can be incorporated as part of general landscape design or as part of a larger streetscape (see Green Streets, Alleys, and Parking Lots, just below). In addition to managing stormwater and reducing nutrient pollution, rain gardens can also reduce temperatures, provide wildlife habitat, and improve aesthetics.14  Rain gardens can be installed in many different areas and do not need to take up much space.

Urban Forestry: Urban forestry is suitable for both public and private properties, including rights-of-way and near existing buildings and homes for shade. Urban trees provide air quality and heat reduction benefits, along with mental health and other social benefits.15  Urban forestry policies can include not only increasing existing canopy (many local governments are setting percentage targets) and planting new trees, but also ordinances to preserve existing mature trees, which provide greater benefits for stormwater and public health than young trees.16  Ongoing maintenance and care can be a concern for urban forestry, as well as balancing canopy goals with power utility concerns, particularly during extreme weather events.




Scaling Up: Integrating Green Infrastructure into Existing Processes

Green infrastructure in this toolkit includes strategies to manage stormwater, reduce urban heat island effects, improve air quality, and promote economic development and other sustainability goals.  Green infrastructure provides an attractive alternative and complement to traditional concrete (or “gray”) infrastructure by making paved and hard surfaces vegetated or permeable. Permeable pavements and green roofs both capture rainfall and retain it on site, keeping it out of the stormwater system, and can also provide wildlife habitat and greenhouse gas reduction benefits.17  Climate change will exacerbate stormwater runoff problems in many places due to more intense storms that could overwhelm existing infrastructure systems; green infrastructure, when installed at a larger scale and in combination with gray infrastructure, can help to manage those more intense storms.  

While many local governments begin experimenting with green infrastructure practices through pilot or demonstration projects, in order for green infrastructure to have a substantial impact on managing stormwater, it must be constructed and installed on a much larger scale. Therefore, local governments are increasingly incorporating green infrastructure practices into their existing laws, policies, plans, and processes, so that its implementation can be more systematic.

 This chapter investigates legal tools designed to integrate green infrastructure into:

  • planning tools (including green infrastructure-specific plans and comprehensive plans),
  • regulatory tools (including zoning and building codes and stormwater ordinances),
  • incentive-based tools (including grants, subsidies, and stormwater fee adjustments), and
  • government operations (efforts involving public infrastructure, land, or facilities).

These tools vary in their ability to reach new construction versus existing development and in reaching public versus private property. Effective green infrastructure programs leverage multiple tools to encourage or require green infrastructure.18  As such, it is prudent to consider each set of tools alongside the others and craft an implementation approach that incorporates many of the tools discussed in this chapter. Similarly, many of these approaches deliberately build off of pilot programs that carefully monitored demonstration projects for effectiveness in managing runoff, reducing nutrient pollution, reducing urban temperatures, and other factors. Many are therefore beginning to “scale up” with rigorous data on the effectiveness of individual projects, and are continuing to monitor on a larger scale for cumulative effectiveness.


Different types of tools can achieve different goals and will face different challenges in enactment and implementation. The following chart compares the types of tools local governments can use to integrate green infrastructure practices into their existing systems along four sets of criteria.19 

New vs. Existing Development:  some tools are better suited for incorporating green infrastructure into new development – these largely include tools that involve permitting or governmental review of some kind such as zoning. Others might also be able to influence installation on existing development – these tools would more often involve incentive-based approaches than regulatory approaches.

Public vs. Private Property: some tools will more effectively influence design and construction on private property, and others on publicly-owned land such as in the public right-of-way or surrounding public buildings. Government operations tools clearly will most directly affect public property and facilities, while regulatory tools will mainly influence private property. Some tools will be able to impact both types.

Administrative: some tools will require higher levels of organization, coordination across agencies, and participation from residents or other private actors to be successful. Because most local governments are starting from some kind of existing program, they must consider how current policies fit with their adaptation and other goals. The “Administrative” criterion captures how complex each tool is along these dimensions.

Legal: Local governments will need to consider which tools fall within the authority that agencies already possess and which may require further granting of authority from either the local legislative body or the state legislature. In addition, certain methods or tools could conflict with current state or local law. To improve current laws, governments can consider consolidating the laws on a particular topic or revising existing ordinances to better enable green infrastructure practices to become regular practice in that jurisdiction. We have attempted here to identify potential legal obstacles for each local government to consider.

The following table compares the types of policy tools that the rest of the chapter describes in order to provide a starting place for local governments to begin to make their own decisions about how to integrate green infrastructure into their own systems and usual processes. It is not a sufficient guide to the intricacies of every potential cost and benefit, nor does it answer specific questions about each jurisdiction’s local law, politics, and geography. Each of the sections of this chapter will explores the methods in more detail, including evaluation of how local governments might implement each one.


How to Pay for Green Infrastructure: Funding and Financing


Communities are increasingly turning to green infrastructure as a vital tool to help manage stormwater and improve climate resilience. However, many local governments seeking to establish green infrastructure programs face budget constraints that may limit the scope or effectiveness of program implementation. Fortunately, local governments have the opportunity to draw upon a wide range of funding sources, revenue models, and financing strategies to support green infrastructure programs. This Funding and Financing Chapter provides strategic guidance on how to pay for green infrastructure. 

Stormwater management is increasingly becoming a major expense for local governments addressing persistent flooding or responding to legal and regulatory mandates, such as combined sewer overflow (CSO) consent decrees,20  total maximum daily load waste load allocations,21  or municipal separate storm sewer system (MS4) permits.22   

Investing in green infrastructure can cost-effectively help communities manage stormwater while also producing significant co-benefits. Examples of co-benefits include improvements in air quality and public health, increased climate resilience, opportunities for community recreation, and enhanced community aesthetics.23 Designing green infrastructure programs to maximize co-benefits may open up funding sources that would otherwise not be available for stormwater management projects or programs. For example, communities can use funds for programs such as transportation and street design, open space and wildlife conservation, or disaster relief to pay for green infrastructure programs. Additionally, communities can implement innovative financing strategies to capture the economic value created by flood costs avoided, increased health benefits, or increased property values. Communities can aggregate multiple funding and revenue sources, or combine a funding source with financing options such as low-interest loans or green bonds.

Green Infrastructure Cost Effectiveness

Green infrastructure can effectively manage the “first flush” of stormwater while producing significant cost savings for local governments. For example, Philadelphia’s city-wide Green City, Clean Waters program is projected to save the city $8 billion over a twenty-five year implementation period compared to the traditional gray infrastructure that would have been required under an agreement with the U.S. EPA to control the city’s stormwater.24 Similarly, Chicago, Illinois, has reported that its green infrastructure installations are more effective at managing stormwater than traditional techniques on a per-dollar basis.25 The Chicago Green Alley Program is estimated to manage stormwater between 3 and 6 times more effectively per dollar compared to traditional stormwater infrastructure.26 However, it can still be hard to find the funds to build and maintain green infrastructure.

This chapter provides descriptions of multiple strategies that a local government can use to pay for green infrastructure program implementation.  The tools covered in this chapter are broken down into five categories. For each of the funding or financing strategies, this toolkit provides an overview of how the mechanism can be used to pay for green infrastructure projects or programs. Linked resources in the Georgetown Climate Center Adaptation Clearinghouse provide more detailed information about funding programs or descriptions of jurisdictions that have successfully paid for green infrastructure projects or programs using the various funding or financing tools. This Chapter explores federal funding sources, state funding sources, local funding models, government financing options, and private financing options (each described in more detail below).27  

Each funding or financing strategy can be compared under a set of decision-making criteria, including:

  • Funding Availability, which includes the ease of getting funds and the ability to sustain them over time. For example, whether a federal program is available every year and calculated by a formula, as opposed to being a competitive grant program.
  • Funding Flexibility, meaning the amount of discretion the local government has to decide how to use the funds, or the breadth of activities that the funds can support.
  • Municipal Budget Impact, meaning whether the particular funding strategy takes money out of the local government’s general fund.
  • Administrative Burden, which includes the time and resources necessary for the local government to administer or manage that funding strategy, in addition to any potential administrative process to begin the program (writing new regulations, for example).
  • Legal Constraints, such as whether the funding strategy is constrained by state statutes that may give the local government legal authority for that strategy (or not), or by related state laws such as, for example, caps on borrowing.


Using Green Infrastructure Strategies to Better Manage Stormwater and Flooding
March 2, 2015
On May 2-3, 2015, the Georgetown Climate Center convened local sustainability officers, stormwater managers, federal officials, and other experts to discuss innovative ways for local governments to incorporate green infrastructure strategies to better manager stormwater and localized flooding from heavy rainfall and changing precipitation patterns from climate change.


Planning Tools

Local governments are increasingly creating plans for their green infrastructure programs and incorporating green infrastructure into other planning documents such as comprehensive plans and general resilience plans. Incorporating green infrastructure goals and practices into those plans can shape local governments’ interventions to be as highly effective and strategic as possible, instead of installing green infrastructure on a more ad-hoc basis.

Green Infrastructure-specific plans

Because green infrastructure can involve so many different agencies, partners, and funding streams, some local governments have created green infrastructure-specific plans to coordinate all of those moving pieces. These green infrastructure plans can accomplish several purposes including prioritizing particular neighborhoods or types of locations (such as streetscapes or parking lots), setting goals for research or monitoring of installations, clarifying relationships among partners, and calling for policy changes to support green infrastructure investments.

Because green infrastructure-specific plans are not regulatory, they can influence behavior for both new and existing development and can affect decision-making on both public and private land. Hoboken, NJ has created a green infrastructure-specific plan that lays out the target neighborhoods and even individual parcels for green infrastructure installation. Because these plans are not regulatory, however, they may need changes in law to implement their recommendations. Hoboken’s plan identifies the zoning changes that would need to happen to generate more green infrastructure on private property.

Comprehensive plans

Local governments use comprehensive plans to set policy and to plan the direction of their communities for years to come. In some localities, a larger jurisdiction such as a county might create the comprehensive plan, which then would guide the zoning codes set by the municipalities in that county. By incorporating requirements for green infrastructure into its comprehensive plan, a local government can thus require or encourage the use of green infrastructure through requirements or incentives in the zoning code for various types of land uses.

Because comprehensive plans shape future changes in zoning codes, they can directly cause green infrastructure to be required for new development and on private property. However, changes to the zoning code generally must happen for the comprehensive plan to be effective in changing construction and development; this can be a long and burdensome process for small local governments, and developers may resist additional requirements.

Different types of planning tools can achieve different goals and will face different challenges in enactment and implementation. The following chart compares green infrastructure-specific plans and comprehensive plans along four sets of criteria, following the discussion of each type of planning tool above.28