1993 Flooding of upper Mississippi Basin

Rivers of the upper Mississippi drainage basin experienced major floods during the summer of 1993. This included the upper Mississippi, lower Missouri, Kansas, Des Moines, Illinois, and other rivers. Millions of acres of farmland and urban areas were inundated for weeks, and property damage exceeded $10 billion. Persistant rains fell throughout much of the region during the spring and summer. Most of the region received 150% of normal precipitation, and some spots had more than 200% of normal rainfall (Melcher and Parrett 1993).

Peak discharges were all-time records on many rivers. Other rivers recorded the greatest discharges, since the time their flows have been regulated by reservoirs and canals. Flooding was unusual because of its relatively late occurrence in the spring-summer runoff season, and because of its widespread and long-lasting nature. No doubt, the magnitude of peak floods would have been much higher without substantial regulation of stream flow. On the other hand, the long duration of flooding was probably caused in part by stream regulation.

Management of flood-control reservoirs is to reduce downstream peak discharge by spreading the flow over longer time intervals. Many dikes, levees, and small dams failed during these floods. However, large structures of the U.S. Army Corps of Engineers functioned properly without serious failures. Based on the outcome of 1993 flooding, engineers and planners are adopting new strategies for flood management, based on less artificial control (dams and levees) and more natural river behavior (floodplains and wetlands).

Flooding in the spring and summer of 1993 was not confined to the Mississippi basin. Significant flooding also took place in the upper Arkansas basin of Kansas and Oklahoma. The following images show the aftermath of flooding on the Little Arkansas River in Harvey County, Kansas. These photos were taken in August, 1993, one month after the flood, which innundated the city of Halstead. Photos courtesy of Rich Sleezer ©. Click on the small images to see full-sized versions.

Scouring of the Little Arkansas River channel. Halstead grain elevator in background.
Damage to bridge of county road over the Little Arkansas River, south of Halstead, Kansas. Much structural damage in floods is caused by drifting debris--trees, railroad ties, barrels, etc.
Used sand bags piled for removal. These bags are made of biodegradable plastic, so they cannot be stored for reuse.

Related information

Reference

ES 341 © J.S. Aber (2009).
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