The Blavet river flows from central Brittany and enters the Atlantic Ocean on the south coast near Lorient. The river is canalized for most of its length and is navigable for smaller craft. It is part of Brittany's canal system and became more important when the western half of that system got cut off by the construction of Lake Guerlédan's hydroelectric power dam. Today, boat traffic coming from Nantes via Redon has to take the Canal du Blavet and the Blavet river in order to reach the ocean near Lorient.