The Lac du Val-Joly is an artificial lake in France, constructed before the 1970s. Located 2 km from the Belgian border, and close to Willies in the Nord département, 183 m asl on the course of the Helpe Majeure, a tributary of the Sambre. It was created with a dam to help regulate the flow of the Helpe Majeure, and also as a hydropower source, and as a source of water to cool the old thermal power station, Pont-sur-Sambre. The lake has many species of fauna (some introduced by humans), and is currently classified as a Special Area of Conservation.