On July 24, Krista Grimm of the League of Women Voters Lake Michigan Region presented a lunch-time lecture to a group of 15 at the McCormick Bridgehouse & Chicago River Museum. Grimm first told listeners how a wetland naturally cleans stormwater by retaining it, filtering it through soil, and allowing microorganisms and roots to transform contaminants. However, because 90 % of Illinois wetlands have been lost, a "gray infrastructure" system is vital. Our local one is designed to handle 2" in 24 hours. With the recent increase in precipitation, including a record-setting storm on April 18, 2013, system overflows have been more frequent, resulting in sewage and runoff being routed to natural waterways before treatment.
To combat environmental damage, Grimm advised residents to take steps such as clearing street drains, using less toxic products, reducing water consumption during rainfall, and properly disposing of pet and hazardous waste. She also provided more costly ideas, including native foliage, rain barrels, rain gardens, permeable paving, and bioswales (also called channels or "drainage ditches") to direct flow. In one example, a homeowner reduced basement flooding by planting black-eyed susans and disconnecting her downspout. One attendee found hope in this plan, because she was worried about flooding but didn't believe she could count on her neighbors to adopt any significant conservation measures.
Grimm also commended the city of Chicago for leading the nation in the number of green roofs, and for installing bioswales throughout the city. She noted the city hall is committed to converting aging infrastructure, but saw room for improvement. "Anything that's impervious has the potential of being made pervious."
For those interested in learning more, the League of Women Voters Lake Michigan Region created a Stormwater Action Kit.