The dam was originally built on this tributary of the Vesdre between 1860 and 1876, and raised between 1967 and 1971. On a 235m rock foundation and reaching 67m in height and 320m length, its capacity has doubled to 26 million m3. From the top of the tower, reached by a lift, there is a fine view of the wooded valley, the lion presiding over the ridge, and the reservoir.