Our Lady Gate of Heaven Church in Calumet. Photo taken after a storm in the summer 2008. Before the bioswale was installed, the parking would be flooded for days after a big rain. The bioswale soaked up this rain after one day.

As Chicago-area residents continue to clean up from last weekend’s storms that dumped more than eight inches of rain in less than 48 hours, it is important to consider why such storms seem to be occurring more often and what we can do to lessen the damage as they happen in the future.

The overwhelming majority of climate scientists agree that human-induced climate change is already altering our planet. The effects of climate change will affect all parts of the planet, including the Midwest, where we can expect more extreme summer heat days, threats to agriculture, and more intense and frequent storms.

Some changes are already occurring. Average yearly temperatures have steadily increased, snow comes to the region later and melts earlier than in the past, and heavy rains occur today roughly twice as often as they did a hundred years ago.

Although climate scientists cannot determine that a single weather event is the result of climate change, observed changes and climate projections suggest that more intense storms will increase as the planet’s climate changes.

The Chicago region, like most, relies almost exclusively on man-made infrastructure – curbs, gutters, pipes and catch basins – that whisk rain away from our streets and parking lots and release it into nearby streams and lakes. This current system is mostly effective, but has significant flaws:

• Existing infrastructure cannot handle the amount of rainfall produced during large storms and will be hard-pressed in the future to handle more intense storms expected in a changing climate. That means households and businesses will continue to experience flooding.
• Rain enters the same pipes that manage the region’s household sewage. When a large storm hits, the rain overwhelms the system, which results in raw sewage overflowing into the Chicago River and, thus, other bodies of water.
• Rain picks up pollutants when it runs off roadways and parking lots. The rainwater carries that pollution through the sewer system and into our streams and lakes, contaminating drinking water sources.
• Whisking rain away from where it falls prevents local aquifers from re-charging, meaning that communities reliant on well water will face water shortages as they grow.

Meanwhile, green infrastructure, using natural systems to manage stormwater by retaining and filtering rain where it falls, can reduce runoff and flooding and remove pollutants. Numerous green infrastructure projects in the region have already made a positive impact on the properties around them. Simple green infrastructure systems installed in 2008 at St. Margaret Mary Church in Chicago’s Rogers Park neighborhood have effectively protected the property from extensive flooding since.

Additionally, many types of green infrastructure offer benefits above and beyond what conventional infrastructure provides. Green infrastructure installations increase the natural beauty and economic value of developed areas, provide habitat and connectivity for plants and animals, clean and re-charge groundwater sources, and reduce the urban heat island effect. Some green infrastructure systems, such as green roofs and rain gardens, may improve air quality and provide benefits for the climate.

Earlier this year, a task force of planners and engineers from the University of Illinois at Chicago (UIC) and the Center for Neighborhood Technology (CNT) completed a green infrastructure analysis mandated by the Illinois General Assembly. The UIC-CNT report concluded that green infrastructure is effective and affordable solution to stormwater runoff and should be implemented across the state.

“The performance of green infrastructure is at the very least comparable to detention approaches to stormwater management,” the report found. And, in terms of cost, the report estimated that “green infrastructure is frequently 5-30% less costly to construct and about 25% less costly over its life cycle compared with traditional infrastructure.

Last month, in a letter to the General Assembly and Gov. Pat Quinn, Illinois EPA director Douglas P. Scott endorsed the findings of the UIC-CNT green infrastructure report and laid out next steps for his agency to implement the report recommendations.

With the likelihood of increased heavy storms in future years due to a changing climate, creating a robust and sustainable stormwater management system is more important than ever before. Green infrastructure will allow us to sustainably adapt to a changing climate as a society, and it will help individual businesses and homeowners keep stormwater out of their buildings.

This entry was posted on Friday, July 30th, 2010 at 12:26 pm and is filed under Featured Portfolio News, Natural Resources. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.