These Proceedings present a summary of the background, objectives, focus, activities, conclusions and recommendations of the Workshop developed along nine days of intense dedication by the participants, lecturers and organizers. This III International Workshop on Regional Approaches to Reservoir Development and Management in the La Plata River Basin is meant to (i) set the arena for an open and multisectorial debate on sustainable development of reservoirs; (ii) host foundation activities of the La Plata River Basin Environmental Research and Management Network (RIGA), which is one of the most relevant activities stemming from the recommendations of the previous I and II International Workshops, and in doing so, (iii) provide continuity and follow up to the previous regional meetings successfully held in 1991 and 1994.