This technical note describes use of a multibeam echosounder (MBES) to
quantity the dynamics of suspended sediment in a large open channel. A
methodology is detailed that uses the backscatter magnitude from the
MBES water-column data to adjust the magnitude of sonar returns for the
various sonar settings, spatially and temporally average the data to
account for the random nature of acoustic backscatter from the
suspended sediment, and calibrate the processed data with direct
samples. A case study of flow at the confluence of the Rio Parana and
Rio Paraguay, Argentina, where there is a distinct turbidity difference
along the mixing interface of the two flows, is used to demonstrate the
unique capabilities of MBES to quantify sediment concentrations and
dynamics within the water column.