Aquatic Sciences Meeting, Albuquerque 2001

PC09 River and Margin Biogeochemistry

Date: Wednesday, February 14, 2001

Location: Southwest Hall

Campanella, R, , Center for Bioenvironmental Research at Tulane and Xavier Universities, New Orleans, USA, rcampane@tulane.edu

Coakley, B, , Department of Geology, Tulane University, New Orleans, USA, bcoakle@tulane.edu

Allison, M, , Department of Geology, Tulane University, New Orleans, USA, malliso@tulane.edu

HISTORICAL BATHYMETRY FROM THE ARMY CORPS OF ENGINEERS FOR THE LOWER MISSISSIPPI RIVER, 1915-1992: EVOLUTION OF A CONTROLLED RIVER

Historical bathymetric data can be used to characterize changes in river channels, but are often not readily available. Surveys conducted in 1915, 1937, 1948, 1964, 1975, 1983, and 1992 and stored on maps have recently been digitized by the Army Corps of Engineers-New Orleans District. For this work, these datasets were gathered from various formats, geo-referenced, interpolated, and differenced. The results depict riverbed aggradation, erosion, and channel migration. From 1915-1948, approximately 44% of the 320-kilometer-long riverbed below Baton Rouge deepened, while 56% aggraded, both by an average of approximately 7.00 meters. These areal percentages remained almost the same during the interval from 1948-1992, but average deepening and aggradation decreased to 4.24 meters. Above New Orleans from 1948-1992, downcutting averaged 4.37 meters, while aggradation averaged 4.75 meters; below New Orleans, magnitudes were 4.08 and 3.28 meters, respectively. For the stretch of river below Baton Rouge, fluctuations in depth appear to have diminished during the interval of 1948-1992. This temporal synopsis of lower Mississippi River channel changes may be used to characterize the river’s responses to increasing development and flood control.

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Aquatic Sciences Meeting, Albuquerque 2001

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