A particularly saturated summer at Midewin

A July 2015 Field Note by Kirsten Rothenbucher, Initiative Intern

In Wilmington, Illinois, it is normal for June and July to be the months in which the most rainfall occurs. That being said, during my summer working on TWI’s restoration projects at Midewin National Tallgrass Prairie, it seemed like every other day there was a downpour of some sort. It is safe to say that a capricious climate with intermittent inundation also affects the wildlife, dams, and habitat of a prairie/wetland, but how so?

Our manager for the Wetlands Initiative's projects at Midewin, Trevor Edmonson, has said more than once that this summer’s rainfall patterns have been quite different than last year's. In addition, the average temperature in June/July at Midewin is considerably milder than last year. However, this was made up for by the heat index and dew point. All of this pent-up energy that forms throughout the daytime due to the heat and moisture explains why there have been such severe and frequent thunderstorms in Wilmington this summer.

Destructive and relentless, flooding is often the main cause of soil erosion. Usually, soil erosion occurs when there is not enough natural vegetation (such as wetland and prairie areas) to soak up rainwater. When an area is covered largely by concrete, there is nowhere for the water to go. This causes flash flooding, and the water wears down the soil wherever possible. This happens frequently on farmland due to the clearing of natural vegetation and plowing of crops.

Naked topsoil is easily blown away during torrents of rain, leaving infertile dirt behind (WWF 2015). Though Midewin is by no means farmland, heavy flooding can produce similar effects in wetland and prairie areas. While these areas are definitely more absorbent, there is only so much water it can hold before it becomes an issue.

This eight-inch catfish was one of many creatures found swimming across the dirt road at Midewin National Tallgrass Prairie after heavy rains. Photo by Trevor Edmonson/TWI.

Flooding of wetlands displaces the habitats of many species. After a torrent of rain in early June, many of the roads at Midewin were flooded. Our rain gauge indicated four inches of rain in just one night. For days, we found crayfish, catfish, sunfish, leeches, and some turtles swimming in the roads. Not to mention, the overwatering of vegetation can make it difficult for plants to maintain their own homeostasis. That being said, flooding can sometimes be an important part of the water cycle.

When there is not enough vegetation to trap and slowly release surface water from precipitation, runoff is generated. Wetlands play an essential role in slowing the speed of floodwaters and distributing them gradually over the floodplain (EPA 2012). The storage and slowing of floodwater reduces the severity of floods and prevents soil erosion. This is the exact reason why preserving wetlands is so crucial. Instead of destroying over 80% of wetlands that used to occupy the areas along the Mississippi River (EPA 2012) and replacing them with expensive levees and dredge operations (which, by the way, do not purify water and provide biodiversity), we can harness the power of flood control and nutrient removal that wetlands provide naturally. Areas downstream of urban regions, especially, are in need of wetlands.

Along with collecting runoff, wetlands can remove pollutants that inevitably end up in the water. During my time with TWI, I also learned about a ground-breaking (pun intended) project TWI is carrying out with local farmers in the Big Bureau Watershed to “construct” wetlands to naturally reduce nutrient runoff (TWI 2015). When a small wetland is precisely sited on farmland, it can remove excess nitrogen from tile-drainage flows before it reaches a major waterway. Not only does this purify harmful runoff, these wetlands can provide habitat for wildlife, increasing biodiversity.

At Midewin, there are two sites that TWI field technicians currently work on. Lobelia Meadows is about 160 acres large, and it contains mostly wetlands. This site is in its fourth and final year with TWI, and will be subsequently handed over to the U.S. Forest Service. South Prairie Creek is the other site. TWI is in year one of restoring some areas at South Prairie Creek, and there is a lot of work to do on this degraded parcel.

Some occurrences of cloudbursts have impacted our day-to-day work on-site, delaying planting or herbicide applications. For the first month of my internship, our activities consisted mostly of planting. When the flooding began, this task became problematic. When planting irises, we were told that the seedlings should be underwater with their leaves poking out at us. However, if the wetland was flooded (which it almost always was), we had to be mindful of the water depth. A few inches of water may seem like a good spot to plant iris, but we had to take into account that the water would recede once the rain let up. This meant we had to plant the iris (and other species) in deeper water than we normally would, which could be troublesome for the plant.

A view of sedges and forbs in bloom at the Lobelia Meadows project. Photo by Kirsten Rothenbucher.

On July the first, we finished planting our 180 trays of seedlings. From there, I obtained my herbicide license, and we have been spraying vetch and dabbing cattails ever since. Rain interferes with this task as well, because herbicide is activated photochemically. Subsequent to herbicide application, there should be at least four to five hours of continuous sunlight. Also, water would dilute the herbicide, making it less harmful to the invasive plant. Since dry, sunny conditions are crucial, this unusually wet summer has been a challenge for Midewin field technicians.

Being a young environmentalist, I have a stewardship mindset when it comes to our earth. I am well aware that we will not achieve perfection in our lifetimes, but that does not stop me from working towards a better environment for future generations. Part of that environment has to include the restoration of the Midwest prairie and wetlands. With climate change becoming an increasing issue, who knows how much rainfall next summer will bring?

Wetlands and other natural habitats are necessary to help us cope with the persistent, erratic weather, as well as reducing the pollution that is contributing to more extreme weather events. If I have learned anything at all during my time at Midewin, it is that our world would become a wasteland with the loss of the wetland biome. Whether it be witnessing (and smelling) the methane gas bubbles in the wetland produced by decomposing matter, observing how wildlife is displaced due to flooding, or viewing how a year four project (Lobelia Meadows) compares to a year one project (South Prairie Creek), my internship has only reaffirmed how much I value natural services.

Kirsten is an Environmental Science major at Lewis University. She interned this summer with the Wetlands Initiative through the Associated Colleges of Illinois’ Conservation Careers Internship ProgramRead Kirsten’s daily blog about her internship experiences, Polarisdust, here.