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A Partnership Opportunity to Evaluate the Effect of a Major Floodplain Restoration along the Illinois River on Water Quality
Background – Emiquon, an hour south of Peoria on the Illinois River, is one of the largest floodplain restoration projects (total of 7,000 acres) in the country outside the Florida Everglades. Emiquon once was the jewel of the Illinois River, supporting diverse and abundant communities of native plants and animals in a complex system of backwater wetlands and lakes. In 1940, Emiquon and most of the floodplain of the Illinois River was isolated from the Illinois River by levee. It has remained drained by active pumping and for a number of years a large portion of the property along the River has been under intensive cultivation for row crop corn. The property was recently purchased by The Nature Conservancy with the goal of restoring the property to a more native pre-disturbance floodplain ecosystem. TNC has developed a restoration plan which includes re-flooding the site and reconnecting the site with the river. They expect to begin the spring of 2005. TNC considers it their premiere demonstration site for work on the Illinois R. and within the Upper Mississippi R. system, with hopes that it will help guide other large floodplain river restoration efforts. The IL State Water Survey has completed preliminary site hydrology studies and a sedimentation model. Two major problems which may hamper the effectiveness of the restoration are both related to the decreased health and water quality of the IL River: increased stressor and pollutant loads since 1940 (suspended sediments, nutrients and other toxic pollutants) and invasive species that now inhabit the River.
Understanding the effect of this type of restoration on water quality is particularly important in light of the impact of excess nutrients from the Midwest on hypoxia in the Gulf of Mexico. The President’s MR/GOM Watershed Nutrient Task Force has identified wetland restoration as one of the actions that are necessary to address the hypoxic zone in the Northern Gulf of Mexico. In the UMRB the States of Illinois, Iowa and Missouri have lost 85, 89 and 87 percent of all of their wetlands, respectively. Minnesota and Wisconsin have lost roughly half of their historic wetlands. Wetlands have traditionally been recognized for their potential to retain sediments, nutrients and contaminants In order to better estimate the acreage of wetlands necessary to reduce the loadings of nutrients to the Gulf of Mexico we need to gain a better understanding of the uptake of nutrients by restored wetlands. We must design a monitoring protocol and network for restored wetlands to monitor these areas to determine their processing of these and other pollutants (including sediments, toxicants, and pathogens). We need to know how these pollutants will affect both the success of floodplain/wetland restoration and water quality down stream. This project gives EPA an unusual opportunity to study and learn from the restoration efforts from pre-restoration to post restoration. Not only will we learn more about how to perform flood plain restoration at such a large scale, but also the effect this restoration has on water quality.
Proposed Initial Studies-NRMRL and Region 5 propose to partner with the TNC, USGS and Universities to begin monitoring the water quality of the discharges from the Emiquon site prior to, during and post restoration and to design a protocol for restored floodplain wetlands in general to determine their effectiveness in processing of these pollutants.
Contact: Joseph Schubauer-Berigan, 513/569-7734, (EIMS#136285)