Green Stormwater Infrastructure
Green infrastructure is a cost-effective, resilient approach to managing wet weather impacts that provides many community benefits. While single-purpose gray stormwater infrastructure—conventional piped drainage and water treatment systems—is designed to move urban stormwater away from the built environment, green infrastructure reduces and treats stormwater at its source while delivering environmental, social, and economic benefits.
Stormwater runoff is a major cause of water pollution in urban areas. When rain falls on our roofs, streets, and parking lots in cities and their suburbs, the water cannot soak into the ground as it should. Stormwater drains through gutters, storm sewers, and other engineered collection systems and is discharged into nearby water bodies. The stormwater runoff carries trash, bacteria, heavy metals, and other pollutants from the urban landscape. Higher flows resulting from heavy rains also can cause erosion and flooding in urban streams, damaging habitat, property, and infrastructure.
When rain falls in natural, undeveloped areas, the water is absorbed and filtered by soil and plants. Stormwater runoff is cleaner and less of a problem. Green infrastructure uses vegetation, soils, and other elements and practices to restore some of the natural processes required to manage water and create healthier urban environments. At the city or county scale, green infrastructure is a patchwork of natural areas that provides habitat, flood protection, cleaner air, and cleaner water. At the neighborhood or site scale, stormwater management systems that mimic nature soak up and store water.
See below to learn about different types of green stormwater infrastructure and examples of where they are implemented locally and nationally. Also, check out our Green Stormwater Infrastructure Bicycle Tour! It highlights local examples of stormwater friendly projects near the regional trails system.
Rainwater harvesting systems collect and store rainfall for later use. When designed appropriately, they slow and reduce runoff and provide a source of water. A rain barrel collecting roof runoff is an example of rainwater harvesting and is a cost-effective, low maintenance form of GSI that can be adopted at a home, business, or community building. Rain barrels capture and store would-be runoff, keeping it out of the storm sewer system and providing source of water for yards and gardens.
Interested in adding a rain barrel to your property? Check out the following resources:
Information on local rain barrel suppliers and builders at Meridian Township's website: http://recycle.meridian.mi.us/rain/
River Network's rain barrel event planning guide:
Follow the GLRC's events calendar for information on local rain barrel sales or workshops
A rain barrel collecting roof runoff
Rain gardens are versatile features that can be installed in almost any unpaved space. Also known as bioretention, or bioinfiltration, cells, they are shallow, vegetated basins that collect and absorb runoff from rooftops, sidewalks, and streets. This practice mimics natural hydrology by infiltrating, and evaporating and transpiring—or “evapotranspiring”—stormwater runoff.
A 1 inch rain event produces 623 gallons of runoff on a 1,000 sq. ft. roof. A rain garden equipped with deep rooted native plants can absorb, infiltrate, and filter this runoff that may otherwise carry pollutants into storm drains and discharge into rivers and streams. They are a low maintenance (and beautiful) wet weather solution!
Local Example: Towar Gardens-Ingham County Drain Commission
Build your own:
Native plant supplier: Wyld Type Nursery
Native plant supplier: Michigan Wildflower Farm
Get involved! Wild Ones Red Cedar Chapter: group meets monthly to discuss and promote native plant landscaping.
An example of a rain garden at the residential level
Planter boxes receive runoff from multiple impervious surfaces, including rooftops, sidewalks and parking lots. Curb cuts refer to gaps in streets, median, and sidewalk curbs that allow runoff to collect in a vegetated area. Plants, soils, and gravel capture and infiltrate water before it can enter the storm drain.
"Grand Rapids Sets Out Their Standard For Controlling the 'First Flush'"
A curb cut to allow water to infiltrate into the ground
Bioswals are vegetated, mulched, or xeriscaped channels that provide treatment and retention as they move stormwater from one plan to another. Vegetated swales slow, infiltrate, and filter stormwater flows. As linear features, they are particularly well suited to being placed along streets and parking lots.
Local Example: Boulevard Bioswales on Linden Grove Avenue, Lansing
Permeable pavements infiltrate, treat, and/or store rainwater where it falls. They can be made of pervious concrete, porous asphalt, or permeable interlocking pavers. This practice could be particularly cost effective where land values are high and flooding or icing is a problem. They can be implemented at the residential or commercial scale.
Local Example: Porous Asphalt on Michigan State University's Campus
Diagram of a Bioswale
Pervious pavement at MSU's IM-West
Green Roofs are covered with growing media and vegetation that enable rainfall infiltration and evapotranspiration of stored water. They are particularly cost-effective in dense urban areas where land values are high and on large industrial or office buildings where stormwater management costs are likely to be high. They can improve stormwater management by reducing runoff and improving water quality, conserve energy, mitigate the urban heat island, increase longevity of roofing membranes, reduce noise and air pollution, sequester carbon, increase urban biodiversity by providing habitat for wildlife, provide space for urban agriculture, provide a more aesthetically pleasing and healthy environment to work and live, and improve return on investment compared to traditional roofs.
Green Roof at the Jackson National Life Insurance campus in Lansing
Trees reduce and slow stormwater by intercepting precipitation in their leaves and branches. Many cities have set tree canopy goals to restore some of the benefits of trees that were lost when areas were developed. Homeowners, businesses, and community groups can participate in planting and maintaining trees throughout the urban environment. Trees also absorb runoff with their roots.
The water quality and flooding impacts of urban stormwater also can be addressed by protecting open spaces and sensitive natural areas within and adjacent to a city while providing recreational opportunities for city residents. Natural areas that shoud be a focus of this effort include riparian areas, wetlands, and steep hillsides.