Change in Lower Mississippi River Secondary Channels: An Atlas of Bathymetric and Photographic Data
Abstract
Historically, the Lower Mississippi River (LMR) flowed over 1,130 miles and had access to a 30- to 124-mile wide floodplain. Overtime, a multitude of engineering activities undertaken to create safer navigation and reduce flood damage shortened the Lower Mississippi River by 140 miles and greatly reduced the floodplain. These engineering activities also included closing dike construction in secondary channels to divert more water to the main channel during low river stages. However, the importance of secondary channels to the overall river ecosystem has led to the removal or notching of many closing dikes to restore flow and connection at low river stages. As part of this overall effort to conserve and restore the function and value of secondary channels, this study provides information on the existing and long-term (1960s-2000s) trends of the channels areas and volume. To do this, bathymetric data and aerial photography were gathered from the New Orleans, Vicksburg, and Memphis Districts, U.S. Army Corps of Engineers.Secondary channels were located in the bathymetric files by looking for islands or bars with elevations > 5 ft Low Water Reference Plane. The secondary channels boundaries were then digitized by drawing a polygon through the crest of the bar and extending it from the ends of the bar across the upriver and downriver mouths to the top bank. Along with river bed models created from the bathymetric data, these outlines were used to determine secondary channel area and volume for each decade (1960-2000). These data and aerial photographs of each channel for each decade are provided to aide in monitoring and restoration planning.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2016
- Accession Number
- AD1020871
Entities
People
- Amanda J. Oliver
- Donald C. Williams
- Erin L. Guntren
- Thomas M. Keevin
Organizations
- St. Louis District, U.S. Army Corps of Engineers