The record rain fall and subsequent flooding events in April emphasize the importance of incorporating green infrastructure initiatives at the site, neighborhood, community and regional scale. Throughout May, we will feature blog posts by Chicago Wilderness members that highlight green infrastructure projects in the Chicago area. Thanks to Huff & Huff, Inc. for kicking off the blog series with a before-and-after account of a constructed rain garden project in Deerfield, Illinois.
By Huff & Huff, Inc.
During the Storm
On April 18, 2013, Chicago area residents woke up to heavy rains and thunderstorms. By 7 am, two to three inches of rainfall fell and water levels began to rise to extreme flood levels surging onto roads and into residential basements. Huff & Huff, a member of the Chicago Wilderness Corporate Council, wondered how the rain garden at Deerfield functioned during this major event.
A Year Before the Storm
In 2012, The Village of Deerfield received an Illinois EPA 319 water quality grant. This grant allowed a 50% reimbursement, up to $10,777, to help control non-point sources of water pollution. The Village decided to install a rain garden to reduce the discharge volume and pollutant load to the local storm sewer system tributary, and thus to the North Branch of the Chicago River. Curb cuts were incorporated into the design, directing stormwater into the rain garden from both the parking lot and the street to capture the runoff. The parking lot serves as one of the commuter parking lots for the Deerfield Metra train station. Huff & Huff staff designed the rain garden, inspected the excavating and construction process, and volunteered over 25 hours to install 1,520 native plants by hand.
A rain garden is a shallow depression planted with attractive native grasses, flowers, and sedges where rain water runoff is collected and allowed to recharge groundwater and encourage evapotranspiration. Rain gardens help to naturally filter out pollutants from impervious surfaces such as roads, roof tops, and driveways. Sediment, organic pollutants, oils, pesticides, as well as bacteria from pet waste are removed from the water before percolating back into local groundwater aquifers. The deep roots from native plants help to prevent flooding by allowing 30-40% more water to infiltrate into the soil when compared to a traditional turf lawn.
Thirty-two species of plants and one shrub species were selected for the Deerfield rain garden based on their ability to handle extremes of wet and dry periods, and variable amounts of sunlight. Examples of species planted include prairie cord grass (Spartina pectinata), cardinal flower (Lobelia cardinalis), marsh blazing star (Liatris spicata), obedient plant (Physotegia virginiana), New England aster (Symphyotrichum novae-angliae), and queen of the prairie (Filipendula rubra).
After the Storm
A week after the great flood of 2013, the Village of Deerfield staff reported that they were pleased to see how well the rain garden performed after the storm and that no problems were encountered. This was attributed to routine maintenance including clearing the inlet grates of debris. “Normal routine maintenance is critical to the success of the designed intent,” explained Jeremy Reynolds, Project Manager of the Deerfield rain garden project.
Rain gardens help to reduce the volume and velocity of storm water flow. This reduces flooding on streets and helps to control capital investment costs related to increasing the size of storm sewers needed in the neighborhood. After the floods of April 2013, it is easy to understand how both functions will benefit a community. Next time you are in Deerfield, stop by the rain garden at Sunset and Elm Streets to see the possibilities for your future green infrastructure projects!