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Romeoville Prairie Nature Preserve

Location: Will County, Du Page Township, T37N, R10E, Sec. 34, Village of Romeoville
Size of area affected by MSCSF-funded work: 15 acres to date
Owner: Forest Preserve District of Will County (FPDWC)
Partners: FPDWC, USACE, CorLands, Illinois Nature Preserves Commission, Commonwealth Edison

Action: Hydrologic study and analysis, modifications to existing stormwater control structures, cutting and removal or shrubs and trees, control of invasive herbaceous species .

Summary: North Section
The sedge meadows at the north section of Romeoville Prairie were once spectacular, but serious incursions of dense stands of cattails have diminished populations of conservative wetland plants. This has not been a case of natural succession by any means; the problem is that extensive loads of silt are dumped into the prairie and wetlands from two 72-inch culverts. The culverts bring over 50 percent of all the runoff stormwater from the town of Romeoville directly into the natural area.

The culverts were present when Will County acquired the site, so legal action against a culprit is not an option. The problems created by the culverts have increased substantially in recent years as Romeoville has been in a period of rapid building and development. Open spaces, pastures and farm fields that once absorbed significant amounts of rainfall are now covered with impermeable surfaces that force the water into sewers or drainage ditches, and ultimately into the natural area.

The water emerges from the pipes on the west side of the property with great velocity, particularly during heavy storms. As the grade flattens out, the water spreads out into the sedge meadow; when this occurs, the water velocity is reduced, energy dissipates, and silt smothers the sedge meadow.

The existing infiltration trench which was installed to capture some of the stormwater has filled with sediment and does not function the way it was designed.

MSCSF funded a much-need hydrologic study to address these problems. The recommendations were approved by the Illinois Nature Preserves Commission in May, 2004, and field work to channel the stormwater away from the high quality sedge meadow is scheduled to begin in 2006.

In addition, 15 acres of buckthorn were removed from the eastern edge of the Illinois Nature Preserve portion of this part of Romeoville Prairie.

South Section
The south portion of Romeoville Prairie is covered with fill. This was already known, but what wasn't clear was how deep the fill was, or how intimidating of a project it might be to remove the material and attempt restoration. Using money from CorLands’ Wetland Preservation and Enhancement Account, the FPD initiated a project to evaluate the fill and determine if removal might be feasible. It was hoped that a program of restoration toward native vegetation might be possible, but another prime goal was to increase the amount of habitat available to two rare turtle species found on the northern portion of the preserve, the Blanding's turtle and spotted turtle.

Soil borings three to four feet deep were taken throughout this portion of the site. Unfortunately, all that was found was the clay and rock fill; there was no native soil profile underlying it. The original soil must have been scraped and used elsewhere long ago.

The south end of Romeoville Prairie is distinctly divided into east and west portions by high tension wires and a right-of-way owned by Commonwealth Edison. The FPD decided that the larger west portions of 27 acres would be left alone; there would be no fill removal. However, FPD staff still hoped to be able to create a vegetative and hydrological structure on the five-acre east portion that would work as additional breeding ground for the turtles. There are no roads or other impediments to the movement of turtles from north to south within the preserve.

For turtles, what plants are present is less important than the size and depth of water features, the density of plant material, and the location of flat sections of open, gravel soil suitable for egg laying. The smaller size of the east portion made it possible to attempt fill removal.

The contractor removing the fill planned to use it in a subdivision the company was working on. However, even though soil borings had been taken before beginning, along the way the contractor encountered sections in the fill that were bluish in color. These turned out to be waste from a foundry that made glass. Even though the foundry sand was not toxic, and it had probably less than five percent of the questionable material present, it couldn't be included in the clean fill required for the subdivision. Illinois EPA determined that there was no process of separation that would allow the agency to declare that none of the foundry sand was present anymore, and so the entire amount of fill had to be deposited in a special landfill, which raised the costs of the project to about two and a half times what had been estimated.

Phragmites, cattails, reed canary grass, and other invasives were treated with herbicide. Earth was excavated to create several areas of shallow, open water. The results are ponds and surrounding areas that provide appropriate habitat for both types of turtles. It's too soon yet to know if turtles are using the restoration site. Egrets and herons do use the new habitat.