A Guide to Green Stormwater Infrastructure and the Growing Benefits of Nature-Based Solutions

As urban environments and their infrastructure expand, so do the amount of impervious surface they create. Where rainwater would otherwise naturally find its way into the soil, those surfaces make it so that it is now prevented and diverted by hardened and water-resistant surfaces such as roadways, parking lots, and rooftops. Stormwater planning addresses this issue.

Traditionally, “gray infrastructure” like sewer systems is designed with a single purpose: move water from one place to another as quickly as possible. Over time this approach has led to increasing issues with flooding, erosion, and pollution to local waterways. In response, green stormwater infrastructure (GSI) has risen in popularity to better manage stormwater by utilizing the natural functions of soil and plants.

By blending nature-based solutions into infrastructure, communities get multiple benefits. Green stormwater infrastructure not only improves the immediate management of runoff but also the long-term resilience of their design.

What is Green Stormwater Infrastructure?

Green stormwater infrastructure (GSI) refers to systems that utilize the inherent qualities of nature-based solutions to improve the management and treatment runoff. Unlike gray infrastructure that consists of only man-made materials such as concrete or steel and is engineered solely to move water, GSI incorporates features that better slow, retain, and filter stormwater through natural processes.

Often involving planting vegetation, reconnecting natural water systems, or using permeable materials, green stormwater infrastructure is designed to replicate the natural hydrological processes by enabling infiltration below ground and evapotranspiration above. This approach treats rainwater as the resource it is rather than as waste while improving flooding, water quality, and a variety of other community benefits that come with a greener environment.

Benefits of Green Infrastructure and Nature-Based Solutions

The advantages of green stormwater infrastructure extend across environmental, social, and economic factors. Aside from obvious benefits to community flooding and natural habitat, this approach is also often more cost effective.

Adding green features, sometimes through the comprehensive planning process, to urban environments also can have wide-ranging positive effects on both quality of life as well as property values for a community where present. In fact, research has shown that properties near green stormwater features can increase in value by around 11%, reflecting the demand for communities that integrate green spaces into daily life.

Below is a quick overview of some of the primary benefits of green stormwater infrastructure for a community.

Flood Control and Water Quality

One of the most pressing challenges in stormwater management is flooding. Gray infrastructure often only shifts the problem from one place to another, channeling water away until systems overflow. By contrast, green infrastructure captures rainfall close to where it falls or diverts it to an area designed to naturally hold and absorb. The natural process of infiltration helps remove pollutants while slowly releasing runoff into groundwater. This reduces the burden on sewers, minimizes the risk of downstream flooding, and prevents the high percentage of pollution caused by untreated runoff entering rivers and lakes.

Air Quality and Heat Mitigation

Urban areas with large amounts of pavement experience the “urban heat island effect,” where temperatures rise due to absorbed and reflected heat. Higher temperatures also worsen air quality by increasing smog levels, posing risks to human health. It’s no secret that vegetation naturally converts CO2 into oxygen, which has a direct impact on improving air quality and reducing greenhouse gases. Drawing on these inherent characteristics, green infrastructure features help counter the urban heat island effect by reducing the amount of reflected heat by shading surfaces, filtering pollutants, and cooling the air through evapotranspiration.

Improved Natural Habitat

Even small green features can have a large impact on natural habitat. Projects that restore streams, reconnect wetlands, or replace outdated culverts not only manage stormwater more effectively but also improve fish passage (along with that of other aquatic organisms) and natural habitat for a variety of species. At the same time small additions of vegetation and tree cover provide homes for birds, insects, and small mammals. Together, these systems contribute to biodiversity and improve the resilience of communities.

Resource and Energy Savings

Green infrastructure also saves resources and lowers energy costs. For instance, green roofs insulate buildings, reducing heating and cooling expenses by up to 12%, while also lasting twice as long (20 vs 40 years on average) as conventional roofs. Permeable pavements help water reach soil and infiltrate. Altogether, these systems reduce embodied carbon footprints, extend infrastructure lifespans, and minimize long-term maintenance burdens.

Green Infrastructure Examples

Green infrastructure takes many forms that are tailored to the site and community needs. Below are some common examples of nature-based solutions in action:

Rain Garden

Rain gardens are shallow depressions planted with vegetation designed to capture runoff from nearby impervious surfaces. They filter pollutants, recharge groundwater, and provide habitat for wildlife such as birds and pollinators.

Green Roof

In an urban environment, rooftops are one of the most prevalent impervious surfaces. A green roof transforms that surface of a building into a living landscape. By covering rooftops with soil and vegetation, green roofs capture rainfall, reduce heat, and extend roof lifespans. They also insulate buildings, lowering energy demands.

Porous Pavement

Unlike traditional asphalt or concrete, porous pavement allows stormwater to seep through the surface into the soil below. This reduces runoff volumes, lessens strain on stormwater systems, and reduces quantities of pollutants that reach the stormwater system.

Reconnected Wetlands & Floodplains

Many historical wetlands and floodplains have been cut off by development over time. Restoring these natural features allows them to serve their natural purpose during heavy rains, pooling and filtering water while slowly releasing it back into the water table.

Bioswales & Biofiltration

Bioswales (or biofiltration swales) are shallow, vegetated channels that collect runoff along roadways or developments. When planted with native plants, swales not only filter stormwater but also enhance the character of streetscapes and support biodiversity.

A Complete Approach to Green Infrastructure

As communities continue to grow and climate conditions become more unpredictable, stormwater management is an increasingly critical challenge. Green stormwater infrastructure offers a proven, cost-effective way to address flooding, improve water quality, and create healthier, more resilient communities. Implementation of this approach is a multidisciplinary process that draws on the expertise of planning, landscape architecture, water resources engineering, and environmental sciences to maximize its value.

By harnessing natural processes, these systems move beyond the limitations of gray infrastructure, blending engineering with ecology to deliver wide-ranging benefits. From improved air quality and habitat creation to reduced energy costs and enhanced property values, GSI demonstrates how infrastructure can serve people, nature, and the economy at once.