We present the results of using Sentinel-2A Multispectral Imager Instrument (MSI/S2) and Landsat-8 Operational Land Imager (OLI/L8) data to monitor river plumes in the eastern Black Sea and from the Rhône River in the Mediterranean Sea. The focus is on exploring the possibility to investigate hydrodynamic processes associated with river outflows, in particular internal waves (IWs). Submesoscale IWs having wavelengths less than 50 m and generated by unstable sharp front of a river plume were revealed and their parameters were assessed. A map of surface manifestation of IW trains in the Gulf of Lions was created based on MSI/S2 images. There are different mechanisms of IW generation in river outflow zones, they are determined by a number of parameters including river discharge, bottom topography and presence of tidal currents or inertial period IWs in the shelf zone. A new phenomenon manifested as a chain of quasi circles was discovered. Inertial water motions were suggested as its prime cause, however, this hypothesis is yet to be investigated. An analysis of OLI/L8 and MSI/S2 data enabled us to consider in detail river debouchment streams. For the first time a wave pattern of such stream in the eastern Black Sea was observed in conditions of foehn winds. Usually, foehn winds are distinctly manifested in radar images. A joint analysis of quasi simultaneous ocean color MSI/S2 and Sentinel-1A SAR images demonstrated how water stream wave-like signatures differ from those of foehn winds. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.