A report by Natural Resources Defense Council recognizes two Illinois cities for leadership in implementing green infrastructure strategies to deal with stormwater challenges. Chicago and Aurora are among the list of 14 U.S. communities highlighted in the Rooftops to Rivers II report (PDF). Green infrastructure helps to eliminate runoff pollution by capturing rain where it falls and using it to replenish plants and groundwater supplies rather than allowing it to enter underground pipes and pollute the water supply.

Green infrastructure includes green roofs, street trees, green space, rain barrels, rain gardens, and permeable pavement. These strategies mitigate flooding, clean water, improve air quality, decrease urban temperatures, and reduce associated energy costs. In addition to their environmental benefits, green infrastructure is more cost-effective than traditional “grey” infrastructure like concrete pipes and water treatment facilities.

Chicago’s water infrastructure was built to address 19th century problems that polluted the city’s water supply and created serious public health problems. Like many older U.S. cities, Chicago has a combined sewer system, which means that sewage and stormwater are not separated. Particularly during heavy storms, but even during rainfalls as small as .67 inches, combined sewer overflow sends waste water into the Chicago River. This water makes its way to downstream communities, and eventually to the Mississippi River and Gulf of Mexico, where pollutants have created a “Dead Zone” that grows larger every year.

Chicago is lauded for covering the rooftops of its public buildings with native plants. The city has nearly 500 green roofs totaling about 5.5 million square feet constructed or in-progress, and provides incentives such as expedited building permits for private building owners who install green roofs. This commitment to green roofs has helped to drive down the cost of installation and establish the city as a world leader in urban sustainability. The city’s green roof program receives the most press, but there’s much more going on to address the great environmental challenges of the day. Chicago is a leader in urban forestry, and spends $8 million to 10 million to plant 4,000 to 6,000 trees each year. The city’s Urban Forest Agenda places the maintenance and planting of street trees at the center of its stormwater management strategy, with the goal of 20 percent citywide tree canopy coverage by 2020. Another initiative, Greening Chicago’s Alleys, aims to line the city’s 13,000 alleys with permeable pavement, which improves water infiltration and reduces runoff. As of 2010, the Chicago Department of Transportation has installed more than 215,000 square feet of permeable pavement in parking lots, sidewalks, parking lanes, bike lanes, and plazas.

These efforts, however, are spread across various city agencies, and Chicago does not have a comprehensive plan to integrate its green infrastructure programs. Furthermore, the city lacks a dedicated funding source and does not require private property owners to use green infrastructure to reduce impervious surface, and the Metropolitan Water Reclamation District has been slow to embrace green infrastructure in its stormwater management strategy. Karen Hobbs, co-author of the report, says that although the city “lacks a comprehensive vision”, “Chicago is poised to do important work around green infrastructure.”

Aurora, however, has successfully integrated green infrastructure across all city departments. This comprehensive approach to stormwater management stems from the city’s dependence on the Fox River both as its water supply and as its economic core. Aurora adheres to a Kane County ordinance requiring rainfall events up to .75 inches to be retained on-site; this water cannot come into contact with downstream areas. Green infrastructure is a key element in the city’s strategy to reduce pollution in the Fox River. As it replaces the combined sewer system with two separate pipes, three green infrastructure pilot projects aim to reduce pollution and stormwater overflow.

Large-scale, expensive capital projects like the reversal of the Chicago River eliminated the flow of industrial waste into Lake Michigan but does nothing to address current issues like flooding and overflow. The $4 billion dollar Deep Tunnel project has reduced the occurrence of overflow events, but still sent nearly 19 million gallons of polluted water into Lake Michigan between 2007 and 2010. And the project’s current phase - the construction of a flood-control reservoir - won’t be completed until at least 2029, more than fifty years after construction began.

The 2012 Chicago budget allocates $147 million for improvements to the city’s aging water infrastructure, including 900 miles of new pipes and upgrades to water pumping stations. Increased water and sewer fees will pay for these improvements. While the century-old network of pipes do require significant upgrades, green infrastructure provides a more cost-effective and environmentally sustainable method of dealing with stormwater and sewer overflow.

“Chicago’s green infrastructure investment is an example for the region about how communities can literally make their waterways cleaner, reduce pollution on our beaches, and reduce the risk of basement flooding – and with a much greater return than with conventional solutions,” said Hobbs.

Image: Flickr/Christopher Macsurak