Green Infrastructure
Forging new partnerships and managing stormwater: MWRD invests in green infrastructure and protects water quality
In its early days, the Chicago region was primarily a marshland, filtering water slowly into the ground without impacting the surrounding area. Flooding was less common because most of the area was not paved, and the ground was able to absorb most of the excess water. As the population grew for one of the world’s fastest growing cities in the late 19th century, development ensued. Buildings, roads, sidewalks and asphalt parking lots were constructed, reducing the green space that once absorbed the water.
Rain water now runs off at a much higher quantity and rate and is directed to sewer system built before increasing population and development. These sewers, which along with the MWRD’s Tunnel and Reservoir Plan deep tunnels, are considered “gray infrastructure,” which handles billions of gallons of stormwater. However, as storms have increased in frequency and intensity, even these valuable gray infrastructure technologies cannot always keep up with all of the runoff, leading to flooded basements and surface flooding.
Green infrastructure (GI) is a stormwater management tool that is designed to capture water and allow it to infiltrate into the ground before it enters the traditional conveyance system. These engineered installations store, infiltrate, and/or evaporate stormwater, thereby mimicking the natural water cycle. By using natural or biological modes of controlling stormwater, GI can store water that slowly soaks into the underlying soil. This reduces the amount of water flowing through gray infrastructure and collection systems that are often overwhelmed by increasingly intense rain events experienced throughout the region. GI can help to reduce those peak flows and alleviate flooding and basement backups. GI practices can be effective in reducing wet-weather flows to combined sewer systems, reducing combined sewer overflows to local waterways, and reducing runoff volumes and improving water quality.
As the regional stormwater authority for Cook County, the MWRD is committed to the use of GI to help reduce flooding while reducing load on the sewer system. The MWRD also recognizes the vital role of local government in addressing flooding concerns through the innovative use of GI. In 2015, the MWRD adopted a Green Infrastructure Plan to increase the acceptance and investment of GI throughout Cook County. Since that time, the MWRD has partnered with dozens of agencies to fund GI projects such as rain gardens, bioswales/bioretention areas, permeable pavement systems, and rain water harvesting systems.
Starting in 2017, the MWRD introduced the Green Infrastructure Call for Projects to scale up its investment into GI. This effort resulted with the MWRD initially partnering with 19 communities and public agencies throughout Cook County to fund and build GI projects. Due to the success of the program, a call for projects has been issued each subsequent year providing millions of gallons of stormwater runoff storage through the use of rain gardens, bioswales, and permeable pavement in parking lots, alleys, and residential streets.
Click here for a video of the Harwood Heights Green Alley Installation
What is Space to Grow?
The MWRD has assisted with the construction of many successful GI projects throughout Cook County, but one program holds a special place. The Space to Grow partnership with the Chicago Public Schools, the Chicago Department of Water Management, Healthy Schools and Openlands transforms elementary school playgrounds using GI. Space to Grow converts Chicago schoolyards into beautiful, vibrant and functional community spaces for physical activity, outdoor learning, environmental literacy and engagement with art, while addressing neighborhood flooding issues.
In addition to providing community members in low-income neighborhoods with safe outdoor spaces to play and stay active, Space to Grow schoolyards help CPS meet daily recess and physical education requirements for elementary schools. These green schoolyards also provide a daily connection to nature, which research has shown helps reduce stress and improve academic performance. The new landscape features capture a significant amount of rainfall, reduce the load on the combined sewer system, helping keep the city’s water resources clean and resulting in less neighborhood flooding. This provides students and neighbors an education about GI techniques and purpose. Since 2014, the partnership has converted 30 school playgrounds to capture more than 5.5 million gallons of water per rain event, equivalent to 8.4 Olympic-sized swimming pools. Click here for more details about each schoolyard.
Most projects are developed on publicly owned land controlled by municipalities and other local governmental organizations. Therefore, partnerships play a key role in implementation, and hearing from communities affected by flooding concerns provides the MWRD a direct path to address the challenges on the local level. In providing communities with funding towards the construction of selected GI installations on public property, the MWRD has created millions of gallons of stormwater retention. GI partnerships have multiplied in recent years through the MWRD’s distribution of free rain barrels and oak tree saplings to offset the regional loss of ash trees and soak up more stormwater. One rain barrel or tree may not play a huge role in mitigating flooding, but by combining thousands of these forms of GI throughout Cook County, each can play a role in diminishing stormwater challenges.
The value the MWRD places on GI is also resonating in the local communities it serves. The first year the MWRD put out a call for projects, there were only three GI submittals. The last two years, after the MWRD developed a more specific GI project application, we received close to 100 applications. Thus, the culture is changing within communities in Cook County due to MWRD partnership opportunities, educational outreach and promotion and heightened concern for record rainfall. Every other year, the MWRD volunteer staff partners with the Water Environment Federation to convert a paved, flood-prone area at a local school into a permeable outdoor classroom that also captures stormwater pollution. The MWRD has also made contributions to other community gardens that promote resource recovery and stormwater management.
GI is an excellent tool because it can be installed in a variety of sizes at a variety of costs. As a community wide initiative, the MWRD encourages communities to think Green when funding local projects and performing community outreach and promoting public education and awareness for GI. This effort is directed at accomplishing a cultural shift in how water management is viewed by society. GI becomes effective at a very large scale – property by property. Everyone can play a role. Cook County residents can do their part to help the MWRD manage stormwater and help improve water quality in the process. Property owners can utilize rain barrels, cisterns, green roofs, rain gardens, permeable paving and natural landscaping, or simply disconnect downspouts from the public storm sewer system.
Bioretention is the use of an engineered system using plants and soil layers to retain stormwater and filter contaminants from runoff before it soaks into the shallow groundwater table. Bioretention is often used in the form of rain gardens or bioswales.
A rain garden uses deep-rooted plants, a sand/soil mix, gravel, and a depression in the ground to retain and filter stormwater run-off. The water then infiltrates back into the ground.
Bioswales are similar to rain gardens but are deeper and longer. Their long channels are designed to slow the speed that water flows across them to filter and retain stormwater. Deep-rooted plants allow water to flow faster into the soil. GI will often use a combination of bioretention solutions in a single project to filter and retain stormwater.
Permeable Pavement includes any type of pavement or pavers that allow water to flow through it. These include specifically designed paver blocks, grass grid pavers, permeable asphalt and permeable concrete. Permeable asphalt and concrete are designed to have open spaces that allows water to pass through. Permeable pavers are designed to let water flow between the blocks in engineered gaps. After water flows through the pavement it slowly filters through a gravel layer and soaks into the soil.
Permeable pavement allows rainwater to be absorbed into the ground, rather than into a sewer. This reduces basement flooding while recharging the groundwater table.
Cisterns and rain barrels are tools used to collect and store stormwater flowing from buildings and roofs for later use. This keeps stormwater out of the sewer system, reducing basement flooding and the load on the sewer system. They also provide free water for uses such as irrigation and cleaning which can be beneficial during drought conditions while saving money for the property owners. Plants do especially well with rain barrel water because it does not contain chlorine or fluoride. Rain barrels are easy to install.
The MWRD doesn’t simply preach the importance of GI, but delivers that value to its own property. As part of its earlier GI endeavors, the MWRD began its native prairie landscape effort in 2003, converting several acres of conventional turf grass to native prairie plants on the grounds of MWRD water reclamation plants (WRPs). The MWRD started exploring permeable pavements in 2008, converting the Stickney Water Reclamation Plant parking area to pervious pavers of different varieties and measuring the effectiveness. The MWRD worked with the Chicago Department of Transportation as a partner in the Pilsen neighborhood green street project in April of 2011. In 2015, the MWRD completed a green roof atop its Racine Avenue Pumping Station. In 2016, the MWRD constructed another permeable parking lot at its Egan Water Reclamation Plant. In 2019, the MWRD joined the Water Environment Federation (WEF) in hosting an immersive training for municipalities, public works departments, contractors and others who are interested in installing and maintaining GI elements.
The Green Neighbor Guide
(Español)
What is the Green Neighbor Guide?
While there are myriad ways to be a Green Neighbor—some actions can be as simple
as not over-fertilizing your lawn and garden, washing and maintaining your vehicles
properly, or planting a native tree—this guide focuses on stormwater management
projects that you can build or install on your property.
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