How Rain Gardens Reduce Flooding, Filter Pollution and Bring Nature Back

A former eyesore in Niles is now a rain garden filled with colorful native plants. “It provides flooding and erosion control for the area and creates a haven for native vegetation and wildlife,” says Katie Schneider, assistant village manager for the Village of Niles.

The Niles Community Rain Garden, established in 2008 where two abandoned buildings once stood, is likely one of the first and largest of its kind in Cook County.

Today, rain gardens are increasing throughout the Chicago region at schools, municipalities, industrial corridors, water treatment plants, park and forest preserve districts—and even in backyards.

Photo courtesy U.S. Fish and Wildlife Service

Rain gardens are depressions in soil filled with vegetation that allow stormwater to soak into the ground. They aren’t permanent ponds but rather places for water to flow more slowly before it reaches creeks, streams and other water bodies.

These gardens also contribute to local biodiversity. “The native plants attract beneficial insects and pollinators and provide beautiful flower displays throughout the growing season,” Thomas says. For example, a monarch butterfly might alight on a swamp milkweed in the rain garden to sip nectar or lay its eggs.

Rain gardens are relatively new in the arsenal of stormwater management techniques. Before settlement, rain filtered through soil, roots and plants in native woodlands, prairies and wetlands, helping maintain clean groundwater. These natural water-purifying ecosystems were removed to make way for homes, roads, buildings and agricultural lands. Streams and rivers became degraded as water ran off the land instead of being filtered by vegetation.

In 1990, stormwater specialists in Maryland designed what they called bioretention systems, or rain gardens, to recreate the natural system of stormwater removal.

Illinois soon began establishing rain gardens in various places and ways. Among the first was the Red Oak Rain Garden, on the University of Illinois Urbana-Champaign campus. Created in 2006, it holds more than 60 plant species, mostly native to the region. As a result, nearby sidewalks no longer flood, and a large red oak tree, once floundering, is healthy. The rain garden also serves as an educational tool to help visitors understand water flow and native plants.

The Niles Community Rain Garden contains more than 4,000 native forbs and grasses that absorb and naturally filter stormwater runoff from 36,000 square feet of nearby impervious surface.

In addition, Schneider says, “The rain garden project embodies the spirit of the Niles community. It’s a collaboration of corporate partners, small businesses, volunteers and local government working towards a common purpose to improve our community.”

The MWRD first launched a rain garden at its Stickney plant in 2009. Today, a 60,000-square-foot garden is filled with swamp milkweed, blue vervain, blue flag iris and other native plants that prefer wet conditions, but can also tolerate drought.

“The rain garden captures stormwater and snowmelt on site, so as not to overload the local infrastructure used to collect water at one of the largest reclamation plants in the world,” Thomas says.

He adds that, like most well-designed rain gardens, water is held for a short amount of time, which prevents mosquitoes from breeding.

The MWRD has helped construct rain gardens at more than 40 schools in the Chicago region. Other rain gardens established with MWRD assistance include the public works facility demonstration rain garden in Oak Park, Chamber Park in Wheeling, the Evanston Civic Center parking lot and along an industrial corridor on Pacific Avenue in Franklin Park.

Park districts, forest preserves and homeowners are also creating rain gardens. For example, the Waukegan Park District built a rain garden next to a parking lot to absorb stormwater runoff and pollutants before they go into its treasured ravine system.

Tori Trauscht, president of the Indian Creek Watershed, installed a rain garden about a decade ago in her Mundelein yard to curb street flooding. Her neighbors did the same. “Now there is nowhere near the flooding we used to have,” Trauscht says.

In addition, they can watch nature right in their gardens, she says, including a hummingbird sipping nectar from blue lobelia.

Schneider says the Niles rain garden offers many places to sit and enjoy nature. “There’s a small bridge that the children have the most fun with,” she says. “It’s right off Touhy Avenue, a major state highway that runs through town,” she continues. “It gives a nice break of landscaped green space in the middle of the busy village.”

Sheryl DeVore has written six books on science, health and nature, as well as nature, health and environment stories for national and regional publications. She is co-author of an upcoming book, Birds of the Midwest, to be published by Timber Press. Learn more at
SherylDeVore.WordPress.com.

How to Build a Rain Garden

A key step in creating a rain garden is choosing the right location with permeable soil at least 10 feet away from structures.