The aim of this work is to deliver the Ralco dam behavior, based on a comprehensive monitoring system, a year of its operation. This dam was built with roller compacted concrete is 155 m, 360 m long crest and a volume of 1.5 million cubic meters. Located within the four highest in the world. We analyze the behavior of the dam itself and the physical environment and environmental product of the formation of a new reservoir, including aspects of hydrogeological changes and degradation of the riverbed, the vulnerability of slopes to landslides and other processes. We conclude that the behavior of the dam and its environment has been generally satisfactory. In the case of the dam highlights some aspects that have some degree of abnormality and should be kept under control.