Fermi National Laboratory

Volume 26  |  September 2003  |  Number 13
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Main Injector Wetlands Mitigation Project

by Elizabeth Clements

At first glance, it looks like just another field of grass.

At least, this is what the ELM Committee's Land Management Sub-Committee initially thought when they pulled up to the three acres of restored sedge wetlands inside the Main Injector ring this past July. With the two necessary items for exploring wetlands on hand, rubber boots and a gallon of mosquito repellent, it didn't take long for the group to realize, as soon as they were waist-high in the grass-like sedges, that the restored wetland is much more than just a field of grass and is actually quite a success.

According to the Environmental Protection Agency, more than one-third of the United States' threatened and endangered species live in wetlands. Thirty-one percent of the United States' plant species grow in wetlands, and up to one-half of North American birds nest or feed in them. Wetlands cover only five percent of the United States' land surface, but they are such important ecosystems that for every acre destroyed, the Army Corps of Engineers requires one and half acres to be replaced.

So in 1991, when part of the Main Injector had to be built through six acres of Fermilab's wetlands, the Army Corps of Engineers required 10.1 acres, of which 3.1 acres are sedge meadow and 7 acres are forested wetland, to be rebuilt in its place.

This butterfly is one of the many Bronze Coppers that Tom Peterson found in the Main Injector wetland mitigation area a few weeks ago. The growing number of wetland species butterflies, such as the Bronze Copper, in the mitigated area is a very good sign that the project is a success. "We had to get a permit to fill the wetlands, and part of the terms were to replace it with ten acres of wetland in the middle of the Main Injector ring," said Rod Walton, Head of the Land Management Sub-Committee. "After we planted in 1992, the wetlands area was monitored by the Corps of Engineers for five years. In 1997, the mitigated area was well on its way, and the Corps agreed that the wetlands were good enough to close the permit. We took over the management of the area, burning it when we could. When the Land Management sub-committee recently went out to the area a few weeks ago, we were all struck by how healthy and diverse the wetlands looked."

It was a very welcome surprise because even though the Main Injector wetlands met all of the Army Corps of Engineers' requirements, most wetland mitigation projects fail. Walton explained that, as the name implies, wetlands need water, but getting the right balance is a challenge.

"Building wetlands is very tricky," Walton said. "Nationwide about 65 percent of all wetland mitigation projects fail, mainly because of a lack of water and a poor design. The elevation is extremely important. If it's too low, you get too much water. If it's too high, you don't get enough.

"You also need the right soils and vegetation. We were very fortunate because our contractor did a nice job of grading. They also saved the soil from the Main Injector construction, and spread it on the new area. We really went beyond the basic requirements and ordered many different species of plants for the area. We took a lot of pains to do it right."

Walton explained that the number one thing that kills wetland mitigation projects is not enough rain during the first year. Getting the elevation just right is only one part of having a successful wetland mitigation project. The other factor, the water, requires a little bit of luck and perhaps a rain dance or two. "As it turned out, the summer of '93 was one of the wettest summers ever," he said. "We had super good luck. Everything got off to a really good start and continued to be healthy and to develop over the years."

The dense sedges, which are grass-like plants, are the main wetland species in the three acres of the sedge meadow wetland. Mountain mint and marsh milkweed also grow in large numbers. Bob Lootens, Chairman of the ELM Committee, is very pleased with the way that the sedges and other plants are growing into the area. "It is really unbelievable the way that the area has changed in just two years," said Lootens. "These wetlands are still young. As the sedges and plants continue to grow, it is just going to keep getting better."

Left to right: Elizabeth Clements, Bob Lootens and Tom Peterson make their way down the hill that used to be a pile of dirt left over from the Main Injector construction. As one of the only hills on Fermilab's property, it is a great place to spot birds, such as the grasshopper sparrow. The healthy and diverse plants are only one component of a healthy wetland ecosystem. Tom Peterson, ELM committee butterfly monitor, also recently found a significant number of Bronze Coppers and Dion Skippers, both wetland species butterflies, in the sedge meadows, which is a very good indication that the wetland mitigation project is a success.

"Bronze Coppers are not very common in this part of Illinois. Although they are found in other places at Fermilab, it is really neat to have that species moving into the mitigation are," Peterson said. "Dion Skippers used to be on a watch list, which is a stage below threatened. The Dion Skipper is strictly associated with the wetlands; its caterpillar feeds on the sedges. The variety of butterflies and the variety of plants in these wetlands make it look like a pretty good habitat."

Peter Kasper, ELM Committee bird monitor, was also surprised by the development of the Main Injector wetlands. "When we first looked at the area a couple of years ago, it didn't seem to hold much water," Kasper said. "The wetlands were a lot wetter than I expected when we looked at it more recently. The area is getting more interesting now."

Wetland bird species are not nesting in the area quite yet, but Kasper hopes that the good variety of plants and insects will start to attract King Rails, a state endangered species, and Virginia Rails. Kasper has also spotted Great Egrets, another wetland bird, in the Main Injector ring, which is another good sign. "This is clearly an area that we need to check more often," he said.

Kasper may not have found the desired wetlands bird species in the mitigated area quite yet, but he did find a significant number of Henslow's Sparrows, a state endangered species, in a section of restored prairie adjacent to the wetlands and a colony of Grasshopper Sparrows on a nearby hill that Roads and Grounds seeded with bluestem grass years ago. "The hill used to be a pile of dirt that was left over from the Main Injector construction," said Kasper. "The grass just came in recently. It was a very pleasant surprise."

The success of the Main Injector wetland mitigation project seems to be a surprise for multiple members of the ELM Committee. "It is much better than I expected in such a short period of time," Lootens said. "The Main Injector wetland is a true success story, which is not always true for mitigated areas."

Walton couldn't agree more with Lootens. "Most mitigations are parking lots or abandoned fields after eleven years," he said. "We put a lot of effort into the project, and just about everything worked well, which doesn't happen that often."

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