Comment on "Suspended sediment concentrations and loads in the lower Mississippi and Atchafalaya Rivers decreased by half between 1980 and 2015" by Scott V. Mize, Jennifer C. Murphy, Timothy H. Diehl, and Dennis K. Demcheck, Journal of Hydrology 564 (2018) 1 11
Abstract The author read with much interest the publication by Mize et al. (2018) on the decrease in suspended sediment concentrations and loads in the lower Mississippi and Atchafalaya Rivers between 1980 and 2015. Researchers interested in sediment dynamics in the lower Mississippi and Atchafalaya Rivers also should be aware that sediment data previously reported for the lower Mississippi Atchafalaya River Basin by the U.S. Geological Survey (USGS) and U.S. Army Corps of Engineers (USACE) were affected by a systematic error in the fines fraction (particle sizes less than 0.063 millimeter) of the suspended sediment concentration. This error affected results reported from October 1973 through February 2015 for two sites on the main stem of the Mississippi River, three sites on the Atchafalaya River, one site on the Old River Outflow Channel, and one site on the Red River. The USGS and USACE identified the error and have revised the results for samples collected from October 1989 through February 2015, as reported by Norton et al. (2019a) and Norton et al. (2019b) The significant conclusion of Mize et al. (2018) and sediment loads modeled using the Weighted Regressions on Time, Discharge, and Season (WRTDS) method were unaffected by the systematic error because the models used data from unaffected sites; however, the background information provided in tables 1 and 2 of Mize et al. (2018) included references to several previous studies that contained results affected by the error. This comment paper identifies which references in Mize et al. (2018) were affected by the error and alerts readers to implications of the data revision.
Journal of Hydrology