Chicago has a long list of things to be proud of, but the current state of the city’s combined sewer system infrastructure is not at the top of that list. The Chicago Public Library reports that the sewer system dates back to the 1850s and currently installed pipes may be a century old.

In fact, flood losses in Chicago and surrounding suburbs cost taxpayers $1.8 billion in subsidized grants, loans, and insurance payments between 2004 and 2014, a figure topped only by hurricane-affected areas along the Gulf and East coasts. Major rain events and regional flooding cause overloading of sewage treatment plants, causing the release of rain-diluted sewage into area waterbodies, including Lake Michigan. The “combined sewer overflow” can carry bacteria, viruses, and myriad agricultural, industrial, and other chemicals into the city’s watershed and onto private and commercial property, regional transportation networks, and natural resources.

These events are occurring more frequently due to increased urbanization and changing weather patterns. Last November, the Fourth National Climate Assessment identified extreme rain events as among the most significant climate trends affecting the Midwest.

Still, the city has made some progress in improving water infrastructure. In 2017, for example, the Metropolitan Water Reclamation District and the Army Corps of Engineers completed the McCook Reservoir, which is designed to hold 3.5 billion gallons of combined sewer runoff from Chicago and surrounding suburbs. The Chicago Infrastructure Trust, founded by the city in 2012, focuses on courting private investors for major infrastructure projects, including replacing the city’s water and sewer lines.

But traditional “gray” infrastructure improvements should not be the only answer. Pipeline and treatment systems are costly, take time to complete, and are often subject to a variety of regulatory and environmental permitting hurdles. The state and city have struggled to secure enough funding to make all the improvements necessary to protect Chicago and suburban residents from stormwater damage. Thus, many cities, including Chicago, have looked to “green infrastructure” options. “Green infrastructure” refers to the use of natural systems to allow stormwater to seep into the ground rather than run off. Green infrastructure can be used to reduce and treat stormwater at its source while also delivering environmental, economic, and social benefits.

Chicago has gradually installed some green infrastructure improvements – such as permeable pavement in bike lanes and alleys – designed to capture and manage stormwater where it falls, thereby reducing the burden on traditional “gray” infrastructure, including pipes, sewers, drains, and collection systems. But the addition of green infrastructure has generally been slow and of small scale, in part because some developers and investors are skeptical about cost and performance issues, while others are simply not aware of green infrastructure opportunities.

The following is just a small snapshot of some of the potential benefits of green infrastructure investment and implementation:

1. Return on Investment: The benefits of green infrastructure include beautification, increased property value, energy savings, local financial incentives, job creation, and a reduction in stormwater-related bills from local utilities, among others. These varied benefits provide a better return on investment than traditional single-purpose stormwater conveyances.

2. Public and Private Cost-Savings: Incorporating green infrastructure has been shown to be an overall more cost-effective investment than gray infrastructure. Green infrastructure often costs less than conventional stormwater controls, and combining green infrastructure with traditional gray infrastructure can also reduce public expenditures on stormwater management systems. For example, New York City recently found that a combined green and gray infrastructure approach provided savings of over $1.5 billion when compared with gray infrastructure alone.

3. Energy Efficiency: Green infrastructure improvements can reduce temperatures by shading building surfaces, by deflecting (rather than absorbing) sunlight, and by releasing moisture into the atmosphere, thereby lessening the heating and cooling demands of buildings and reducing owner energy costs.

4. Increased property value: Living among green infrastructure can improve property value by as much as 30 percent and provides mental and physical health benefits to users.

5. Job Creation and Competitive Advantage: Developers and engineers can capitalize on the versatility of green infrastructure improvements in a new market. Various states, counties, and municipalities across the U.S. have developed manuals to emphasize the best green infrastructure approaches for different physical landscapes and development types. Also, designing and installing green infrastructure projects requires labor; thus the private sector can help stimulate job growth in various areas, including finance, construction, and horticulture.

As Chicago and surrounding areas continue to suffer from problems associated with aging water lines, increased flooding, and stormwater pollution, the construction, finance, and real estate industries, among others, could see these and other cost-saving benefits by considering green infrastructure improvements as part of their business models and approaches to stormwater infrastructure development.