MEASURING BEDLOAD TRANSPORT AND SUSPENDED LOAD ON THE MISSISSIPPI RIVER AT THE OLD RIVER COMPLEX

Bedload transport on the Mississippi River was computed using the ISSDOTv2 method for data collected at the Old River Complex. This method uses difference plots of time sequenced bathymetric data for the computation of bedload transport. Bathymetric data were collected at several different sites on the main stem Mississippi River, the outflow channel, the Red River, and the Atchafalaya River, in February 2010. At each site multiple bathymetric swaths, temporally sequential and laterally adjacent across the river, were surveyed. Each survey trip captured two or more time varying bathymetries for each swath. Multiple difference plots were created from these swaths and the ISSDOTv2 computational method was then applied. The output for a given difference plot is a bedload transport value for the swath in tons per day. The values for each swath can be summed to provide the total bedload transport at a section. Flow and suspended sediment measurements were obtained concurrently with the bathymetry. The results of the bedload measurements are combined with the flow and suspended sediment measurements to provide insight into the sedimentation dynamics of the Old River Complex.