Particle size distribution of main-channel-bed sediments along the upper Mississippi River, USA

Geomorphology
By: , and 

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Abstract

In this study, we compared pre-lock-and-dam (ca. 1925) with a modern longitudinal survey of main-channel-bed sediments along a 740-km segment of the upper Mississippi River (UMR) between Davenport, IA, and Cairo, IL. This comparison was undertaken to gain a better understanding of how bed sediments are distributed longitudinally and to assess change since the completion of the UMR lock and dam navigation system and Missouri River dams (i.e., mid-twentieth century). The comparison of the historic and modern longitudinal bed sediment surveys showed similar bed sediment sizes and distributions along the study segment with the majority (> 90%) of bed sediment samples having a median diameter (D50) of fine to coarse sand. The fine tail (≤ D10) of the sediment size distributions was very fine to medium sand, and the coarse tail (≥ D90) of sediment-size distribution was coarse sand to gravel. Coarsest sediments in both surveys were found within or immediately downstream of bedrock-floored reaches. Statistical analysis revealed that the particle-size distributions between the survey samples were statistically identical, suggesting no overall difference in main-channel-bed sediment-size distribution between 1925 and present. This was a surprising result given the magnitude of river engineering undertaken along the study segment over the past ~ 90 years. The absence of substantial differences in main-channel-bed-sediment size suggests that flow competencies within the highly engineered navigation channel today are similar to conditions within the less-engineered historic channel.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Particle size distribution of main-channel-bed sediments along the upper Mississippi River, USA
Series title Geomorphology
DOI 10.1016/j.geomorph.2016.04.012
Volume 264
Year Published 2016
Language English
Publisher Elsevier
Contributing office(s) Upper Midwest Environmental Sciences Center
Description 14 p.
First page 118
Last page 131
Country United States
Other Geospatial Upper Mississippi River
Online Only (Y/N) N
Additional Online Files (Y/N) N