The 2008 Midwest flooding impact on soil erosion and water quality: Implications for soil erosion control practices

Birl Lowery is professor in the Department of Soil Science and Pete Nowak is professor in the Gaylord Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, Wisconsin. Craig Cox is Midwest Vice President of Environmental Working Group, Ames, Iowa. Dean Lemke is chief of Water Resources Bureau, Iowa Department of Agriculture and Land Stewardship, Des Moines, Iowa. Kenneth R. Olson is professor of soil science in the College of Agricultural, Consumer, and Environmental Sciences, University of Illinois, Urbana, Illinois. Jeff Strock is associate professor and soil scientist in the Department of Soil, Water, and Climate and Southwest Research and Outreach Center, University of Minnesota, St. Paul, Minnesota. T he winter of 2007–2008 produced record snowfall in parts of the US midsection, and the spring of 2008 caused record flooding in this part of the country. These floods were once-in-alifetime events for all of Iowa, southern Wisconsin, southeastern Minnesota, and northwestern Illinois. However, given the expected extreme weather events predicted to take place because of global climate change, this kind of weather might become what we can expect as normal. If this is the case, we need to change our management approach for our most precious natural resources—soil and water. While the floods caused enormous financial loss of infrastructures in some urban and rural areas, our soil resources were devastated because of record erosion levels on upland soils. Estimated soil erosion levels from sheet, rill, and gully erosion were far in excess of any imaginable “tolerable soil loss” level (not that any soil loss is tolerable). Soil erosion caused by these floods will have a double impact on natural resources in that the environmental impact resulting from the erosion, in most cases, resulted in impaired water quality because of sediment deposition in waterways, streams, rivers, lakes, and reservoirs; or, the soil will eventually just be deposited in the Gulf of Mexico and contribute to the ongoing hypoxia. Entrained with the sediment were agricultural chemicals and fertilizers imparting a source of pollution to these waters. Soil erosion caused by these floods brings into question current soil conservaFeature