Built in a stranglehold in the Romanche Valley, the Chambon Dam swallowed up the hamlets of Chambon, Dauphin and Parizet. It regulates the flow of the stream: the surplus stored during summer and autumn is directed through the turbines in winter. Within the category of gravity dams with a triangular section, it is 294m long at the crest, 70m thick at the base and about 90m high (137m with the foundations). The reservoir has a surface area of 140ha.