Environmental Progress - Spring 2000

Replacing Gullies and Garbage With Tall Grasses and Flowers

An abandoned Christian County landfill is turning into a prairie

(top) Prairie flower seeds are colored to ensure even distribution. (bottom) Controlled burns eliminate unwanted plants and encourage native grasses.

Not so long ago, in Christian County in central Illinois, there was an abandoned landfill with some problems. Though it had been given a single layer cap and been seeded as part of a roughly $350,000 effort to seal it in 1984, by 1988 deep gullies were eroding down its sparsely vegetated sides, low areas were holding pools of stagnant water, and a stream that ran along one side was cutting into the base.

Corrective action was designed but ownership turned out to be difficult to determine and it was not possible to move ahead. It was 1997 before the necessary Chain of Title was obtained and the owner was notified. He did not respond.

The conventional corrective approach would have been to fill the eroded areas, re-contour the whole thing, add two feet of clay and 100 pounds of fresh seed per acre. Even a modified approach called for applying a six inch layer of top soil, adding nitrogen, phosphorous and potassium to enrich the barren soil and approximately 10 pounds each of fescue and rye on each of the 20 acres. The topsoil, fertilizer and seeds for the modified approach were estimated to cost $978 an acre, not including surface preparation or seed application. Fescue and rye are normally used because their shallow roots won't damage the impervious covers usually installed when closed landfills are sealed.

The former Broverman landfill, located between Taylorville and Kincaid in Christian County, lacking an impervious cap, and not producing methane, appeared an ideal candidate for an innovative prairie plant approach. Prairie plants do nicely in the kind of soil at the landfill, so no nitrogen or phosphorous would be needed,in fact, if added they would probably only encourage weeds. Prairie plants set deep and extensive root systems which would help hold the thin soil cover in place to prevent future erosion.

Unlike conventional cover plants, prairie plants could be seeded through existing cover with a no-till drill, eliminating the need for spreading a layer of topsoil or disking a layer of organic material into the top foot of existing cover. Once the prairie plants established themselves, the only maintenance required would be periodic controlled burning.

Best of all, the estimated cost per acre was $419, less than half the fescue/rye approach.

Erosion didn't wait for owner to be found

(top) Erosion was cutting gullies at the landfill. (bottom) New prairie cover is flourishing.

During the time that elapsed before the current owner of the property was identified, erosion had continued. By the time restoration began in the spring of 1998, the amount of top soil needed to fill the eroded gullies had tripled and buried trash was beginning to surface where the creek continued to eat away at the landfill's base

In May 1998, the large surface irregularities were filled in, rip-rap was added in drainage ways to deter future erosion, vegetation mats were installed and the area was seeded with native grasses and wildflowers.

Green shoots were appearing just a week after the seeding. The plants were expected to show only about one foot of growth in their first season, while they sent down roots four feet deep.

In April 1999, project manager Sue Doubet of the IEPA's Bureau of Land, made a final inspection visit to the site and found growth established on the top and sides of the mound and thick green grass along the creek where emergent buried trash had been visible. A colorful array of prairie wildflowers were in bloom.

In November 1999 an open burning permit was obtained and a prescribed burn was conducted by an expert in prairie restoration. IEPA staff helped control the flames. These fires serve several purposes; eliminating non-native plants and encouraging prairie growth by opening hard shelled seeds and promoting deep root growth.

The site has been turned over to Christian County, a delegated county, for continued monitoring. The innovative approach has worked out so well, the IEPA is now developing plans to "plant prairies" at several other problem landfill sites, and included prairie plants among other stabilization efforts at the threatened Paxton Landfill in Chicago, described in the Fall 1999 issue of Environmental Progress. The prairie restoration work at Taylorville cost a little less than $162,000. IEPA attorneys have filed a lien on the property covering both closure efforts so the owner cannot sell or develop it without first repaying the funds spent by the state.