Significant river discharges are usually associated with episodic rainstorms, leading to turbid storm water plumes clearly visible in the vicinity of river mouths. The composition of the suspended particulate matter transported by these plumes can alter the quality of coastal waters. The survey of marine coastal zones has thus become a major issue for water managers. For several decades, satellite imagery has allowed the daily monitoring of river plumes behavior over large distances. Nevertheless, it fails to provide data on their hourly evolution, which is important to operationally manage coastal waters in tourist areas. This study investigates the possibility of using the Argus video system to continuously survey the evolution of a storm water plume impact region. The system was installed in Anglet, at the Adour River mouth (southwest of France), in February 2005. An image-processing technique, based on pixel intensity clustering, is proposed to delineate river plume fronts along beaches from images collected with the Adour video station. Application of this technique, tested on storm water runoff plume events occurring under different climate conditions, shows promising results.