Demolition before restoration: Tackling a new area of Midewin

Through a major ongoing partnership with the National Forest Foundation and the U.S. Forest Service, the Wetlands Initiative is doing significant restoration work this year within a new area at the Forest Service’s Midewin National Tallgrass Prairie called the South Prairie Creek Outwash Plain.

The National Forest Foundation (NFF), a nonprofit chartered by Congress to promote the health and public enjoyment of the National Forest System, has targeted restoration of the outwash plain as part of its nationalTreasured Landscapes conservation campaign. Midewin, located near Joliet an hour’s drive south of Chicago, is one of 14 National Forests and Grasslands where the NFF is supporting restoration and community stewardship efforts through this campaign.

The National Forest Foundation is demolishing old concrete Army ammunition bunkers on the South Prairie Creek Outwash Plain at Midewin, clearing the way for TWI habitat restoration. Photo by Trevor Edmonson/TWI.

The NFF selected TWI as the organization to carry out the on-the-ground restoration of native wetland and prairie habitats on the outwash plain, and is providing major funding for this work. Meanwhile, the NFF is overseeing the removal of 55 concrete ammunition bunkers that still remain on the outwash plain, dating from when Midewin was the site of the Joliet Army Arsenal. Sixteen of the bunkers have been removed to date.


“As the bunker removal progresses, it opens up new areas for us to move in and restore,” said Gary Sullivan, TWI senior ecologist and the project manager. “We’re working on about 320 acres now, and eventually the goal is to transform the entire outwash plain back to a landscape of high-quality wetlands and prairies.”

The name “outwash plain” refers to an area where glacial meltwater has re-sculpted the landscape, making it relatively flat and depositing gravelly sediments. South Prairie Creek flows through this outwash plain at Midewin and then into the Kankakee River.

The South Prairie Creek Outwash Plain was once a rich mosaic of wetlands, prairies, and meandering streams, but it has been extensively altered by manmade features like drain tiles, old road beds, and drainage ditches. These changes also opened the door for invasive species, which have overrun the native plant communities in many areas. TWI is reversing the drainage, removing invasive plants, and planting a great diversity of native grasses and wildflowers on the outwash plain.

In 2013 and 2014, TWI disabled more than three miles of agricultural drain tiles that were artificially draining a portion of the outwash plain and also removed gravel road beds and drainage ditches that were disrupting the area’s natural water patterns. With hydrology restored on the initial targeted acreage, native plant communities are reestablishing. To enhance the area’s biodiversity, this month TWI is scattering seed of native species over about 100 acres of ground and will plant many plugs (seedlings) in the early summer.

The ladies' tresses orchid.

The ladies' tresses orchid.While ecological restoration is a multi-year process, these efforts are showing early results: “Last summer we saw a huge flush of sedges [grass-like wetland plants] in an area that was not wetland before, so we’re definitely seeing a response to the hydrologic restoration,” said Dr. Sullivan. “This coming year, the wetland areas will fill out more and start looking great.”

TWI is also working to protect and expand populations of rare native plants that have persisted in remnant habitats on the outwash plain, such as the ladies’ tresses orchid. This showy orchid, with spiraling white flower spikes that give off a strong scent like vanilla, is a fairly sensitive species that can’t be transplanted readily. To expand the plant’s footprint on the site, TWI is collecting seed from the orchid to be spread in other areas once they’re restored sufficiently.

The Wetlands Initiative’s current work at South Prairie Creek continues through September 2015, with additional restoration expected in coming years. This effort helps achieve the goals of the shared 10-year vision for Midewin, which was developed in 2011 by all the Midewin partners through a process led by the NFF.

Once intensive restoration of the outwash plain is finished, it will become part of a much larger natural corridor of restored habitats on Midewin’s west side, connecting with TWI’s Lobelia Meadows restoration site and four previous TWI–Forest Service restoration projects. This vast corridor will provide critical habitat for rare bird and wildlife species and allow the public to experience Illinois’ original prairie landscape on a scale found nowhere else in the region.

Read about NFF’s Treasured Landscapes campaign at Midewin: 

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