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Citation
| Johnson, G.P., Holmes, R.R., Jr., and Waite, L.A., 2004, The Great Flood of 1993 on the Upper Mississippi River—10 Years Later, U.S. Geological Survey Fact Sheet 2004-3024. |
Abstract
| Ten years ago, the upper Mississippi River Basin in the Midwestern United States experienced the costliest flood in the history of the United States. The flood came to be known as “ The Great Flood of 1993.”The Mississippi River drains pproximately 40 percent of the continental United States (approximately 1.25 million square miles; fig. 1), and portions of two Canadian provinces, Ontario and Manitoba. During the summer of 1993, the Upper Midwest experienced extremely high amounts of rainfall. An abnormally stationary jet stream was positioned over the central part of the Nation during this time. Moist, unstable air moving north from the Gulf of Mexico converged with unseasonably cool, dry air moving south from Canada.The magnitude and severity of the resulting flood event was overwhelming. The areal extent, intensity, and long duration of the flooding makes this one of the greatest natural disasters ever in the United States. At least 48 people lost their lives as a result of this extreme flood (Interagency Floodplain Management Task Force, 1994). Over 500 river forecast stations in the Midwest were above flood stage at the same time. Nearly 150 major rivers and tributaries flooded. Banks and channels of many rivers were severely eroded, and sediment was deposited over large areas of the flood plains of the Mississippi, Missouri, and Illinois Rivers. Economic damages approached $20 billion (National Oceanic and Atmospheric Administration, 1994). Levees were broken; farmland, towns, and transportation routes were destroyed; and more than 50,000 homes were damaged or destroyed (Josephson, 1994). Water-quality threats to public health and safety were of paramount concern. These threats included contamination of drinking-water supplies, disruption of wastewater-treatment plant operations, failure of septic systems, and risks associated with the inundation of facilities that handle hazardous materials. |
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