Green Infrastructure Design Strategies

Properly designed green infrastructure provides the greatest benefit to water resources and the community. Municipalities and site owners typically hire design professionals such as engineers and landscape architects to identify green infrastructure options and create a site design. Many municipalities also have engineering staff who can perform these duties. This webpage provides an overview of the design process and specific design considerations, but it is not a comprehensive resource for green infrastructure design. Design practitioners should visit their respective state and municipal resources for design guidance, manuals, and requirements, as they vary throughout the country and are dependent on location.

Design practitioners can engineer green infrastructure for sites of various scales—even the most constrained sites—but must tailor designs to address site-specific conditions. For example, a site with poorly draining soils might require a design that does not rely on infiltration. Learn more on our Types of Green Infrastructure webpage and with EPA’s Space Limitations and Low Impact Development: LID Practices are Well-Suited for Small Spaces (EPA 841-F-16-010) (pdf) document.

On this page:

Engage the Community through “Visioning”
Evaluate Your Site
Design with Maintenance in Mind
EPA Green Infrastructure Design Strategy Tools
Design Strategy Resources

Engage the Community through “Visioning”

Working with a designer to create sketches, develop renderings, or convene intensive planning sessions—also known as design charettes—allows interested parties to provide meaningful feedback on different ideas for infrastructure improvements that embody the community’s look and feel. Completing these types of visioning exercises allows participants to see ideas on paper and refine options through feedback sessions. It is important to ensure designs support the goals identified by affected parties during the planning phase. Community visioning examples include:

EPA’s Greening America’s Communities program provided design charettes that helped cities and towns develop an implementable vision of environmentally friendly neighborhoods that incorporate green infrastructure and other sustainable design strategies.
EPA’s green infrastructure technical assistance projects helped communities develop concept designs and feasibility studies for green infrastructure projects.

Evaluate Your Site

Green infrastructure can have flexible designs and has been successfully installed throughout the country in all types of climates and locations. However, each type of green infrastructure requires certain physical site characteristics to function properly, and understanding a site’s features is important to ensure that design practitioners select and then optimally engineer the appropriate green infrastructure. It is also important to work with design professionals with appropriate green infrastructure experience who understand the site-specific nuances and regulatory requirements for a project’s location.

Low Infiltration Rates

Sites with soils that have low infiltration rates will require green infrastructure designs that have underdrains or the capability to drain water away rather than soak it into the ground (i.e., infiltrate). Low infiltration rates may be due to the type of soil present—such as clay—or poor urban soils that are compacted. There are also many types of green infrastructure that do not depend on soil conditions, such as rainwater harvesting, green roofs (pdf), and grassed swales (pdf).

Protecting Groundwater

Many types of green infrastructure can be designed to infiltrate stormwater and promote groundwater replenishment. In these infiltrating practices, the bottom layer of the green infrastructure should be adequately separated from the water table to aid infiltration and maximize pollutant removal before reaching groundwater. To manage this potential risk to groundwater quality, stormwater managers and designers should consider a number of factors when planning for, designing, siting, and operating and maintaining green infrastructure that either infiltrates into or intersects with the groundwater.

Green infrastructure that infiltrates into or intersects with the groundwater should not be sited in locations that receive stormwater from hot spots or brownfields without proper consideration. Hot spots are areas where the designated land use or related activities, can generate high pollutant loads with the potential to impact stormwater. Brownfields are areas of development or reuse where hazardous materials or pollutants are present.

Learn more about groundwater considerations on EPA’s Green Infrastructure and Groundwater Protection webpage.

Semi-Arid and Arid Regions

EPA's Region 8 green infrastructure resources provides many examples of green infrastructure tailored to the arid western and southwestern United States as well as tools and guidance for the region. Design practitioners should view their project’s specific state and municipal resources for design guidance and requirements.

Vegetation

Many types of green infrastructure include vegetation in their designs. Designers must select appropriate vegetation for the type of green infrastructure (e.g., water-tolerant plants for types of green infrastructure that detain water) and geographic climate (e.g., salt tolerant plants that manage stormwater from roadways and parking lots in cold climates). Designers should specify the use of native plant species where possible.

Design with Maintenance in Mind

To avoid unexpected issues and unnecessary costs, green infrastructure projects should be designed with maintenance in mind. For example, selecting vegetation that thrives in the local climate (i.e., native vegetation) may reduce the need for watering, weeding, or replacing plants. In addition, it is important to ensure there is adequate space and access to get necessary maintenance equipment to the green infrastructure.

There are several factors to consider when selecting green infrastructure for your project:

What kind of vegetation can be installed to survive without intensive maintenance?
What regular maintenance tasks will be needed?
How often will maintenance be needed?
What resources (e.g., labor, time, equipment) will be needed to perform maintenance?

The frequency and type of maintenance will depend on the type of green infrastructure and where it is located. Communities should choose green infrastructure that they have the capability to properly maintain (i.e., have the staff and necessary equipment) in order to protect their investment and extend the life of the green infrastructure. Learn more about incorporating maintenance considerations into designs on the Green Infrastructure Installation, Operation, and Maintenance webpage.

EPA Green Infrastructure Design Strategy Tools

A variety of tools can support design visioning exercises. Outputs from these tools can help establish baseline conditions and inform planning and design decisions. They can also help with the initial design steps of identifying which types of green infrastructure may be feasible to implement at a site. Examples include: