Author(s): T. Nakato; J. Anderson
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Keywords: Mississippi River; Bank erosion; Soils; Navigation pools; Channel improvements
Abstract: In order to assess existing river-bank conditions along the Upper Mississippi River reach between St. Paul, Minnesota and Cairo, Illinois at the Ohio River confluence, a field survey of bank-erosion sites was conducted during September and October 1995. Much of the bank erosion in the Corps of Engineers St. Paul District, the upper one-third of the reach, was found at dredged material placement sites and along Holocene-aged landscapes. In the Corps of Engineers Rock Island District reach, the middle reach, historical deposits were thicker along the channel margins, and erosion of Holocene surfaces was most severe in the upper portion of each pool. In the open-water reach downstream from St. Louis, the lower one-third of the reach, the continuous levee and open-water river system revealed significant re-working along the channel margins with scarps more than 6-m high, indicating frequent historical alluvial sequences. However, the Great Flood of '93 and the floods of '94 and '95, particularly along the middle and the lower study reaches, had left extensive erosion scours and encompassed most of the secondary failure and erosion features due to other causes. On the basis of the field investigation, approximately 14 percent of the Upper Mississippi River banks was estimated to be actively eroded as of 1995.
Year: 2003