News

Spring Brook Creek Finds Flow

Spring Brook Creek once leisurely snaked its way across DuPage County, supporting wetlands and providing habitat for small fish and invertebrates. In the 19th century, though, hardworking Naperville farmers straightened the wayward stream into a ditch to increase the amount of tillable land. Today, the Forest Preserve District of DuPage County has begun to recreate the freely flowing and twisting stream where it flows through Springbrook Prairie, a 1,849-acre mix of wetlands and prairie in south Naperville.

Old plat maps show how profoundly the farmers altered the creek. The 1874 plat shows a small offshoot crossing Book Road, like a delicate pointing finger. By 1904, farmers had reined in that small branch, lengthened it, and sent it northward across Book Road again, creating what resembles a large C. The resulting smooth channel drained the soil for farming, but the fast-moving water gouged the banks, carrying sediment and killing fish and invertebrates. Invasive European black alders lined the banks and choked the prairie. Even so, Spring Brook is still the highest-quality stream in the county.

Unlike Nippersink Creek in McHenry County, which was restored to its original course, traces of Spring Brook’s original streambed have disappeared into the landscape. The district doesn’t aim to return the creek and preserve to presettlement conditions. “We can’t go back,” said Leslie Berns, manager of natural resources for the Forest Preserve District of DuPage County.

Instead, the district is working on a $2.2 million project that will chart a new meandering course for an initial section of 1.2 miles, slowing the water and creating better habitat for aquatic life. Banks will be lower, allowing for more flooding and “refueling” of wetlands. The goal is to create a biologically diverse stream.

It is a complex process. The work involves taking measurements from an unchanneled portion just downstream to determine where turns and ripples should be, regrading floodplain levels, pumping water out, and manually moving mussels and other creatures. In time, the aquatic life from the higher-quality section downstream of the work site will make its way to the new oxygen-rich bends and riffles. As alders continue to be removed, the prairie will be reseeded with native species.

The project will benefit more than fish and mollusks. Steward Joe Suchecki is looking forward to increased bird habitat. Alder removal has already begun to open up the large central prairie to grassland birds, and improved stream quality will attract wetland birds such as herons and ducks. “It’s going to be a great improvement,” he said.

— Elizabeth Riotto