This study examines turbulence and sediment suspension over large sand dunes in the Río Paraná.. An acoustic Doppler current profiler was used to measure three-dimensional velocity, and at-a-point suspended sediment concentration and particle-size were measured with a laser in situ scattering transmis-someter. Phase coherence wavelet analysis of time series indicates that fluid ejections sourced near the bed suspend sand into the overlying flow.