River mouth plume-dispersion patterns can be now observed with unprecedented resolution thanks to the most recent generation of satellite imagery products. Various types of thermal and visible images (Advanced Very High Resolution Radiometer [AVHRR], Sea-viewing Wide Field-of-view Sensor [SeaWiFS], and Moderate Resolution Imaging Spectroradiometer [MODIS]) have been used to describe plume-formation events, their association with coastal oceanography, and their dispersal in the northwestern Mediterranean Sea. At this location, two of the largest Mediterranean rivers (Rhone and Ebro) open into this virtually land-locked sea in addition to more than thirty smaller rivers. The analysis has been completed with hydrological and meteorological data, thus integrating information from watersheds and the marine areas under their direct influence. Furthermore, we discuss whether flood events in the study area, as conditioned by riverine, oceanographic, and climatic factors, are increasing or decreasing in frequency and size as a consequence of climate change and human impact, an issue that deserves further study.