The Merrick Hills, the Rhinns of Kells and the Glenkens form the catchment area for the Dee River System in Galloway (see map). Loch Dee and the Silver Flowe are the source of the Dee River that flows through Clatteringshaws Loch, the Otter Pool, along the Raiders Road to Loch Stroan and in to Loch Ken. Joined by the Water of Ken and Water of Deugh, which flow through Kendoon Loch, Carsfad Loch and Earlston Loch, the Dee flows on to Tongland and to the sea at Kirkcudbright.

Seven dams were built along the fifty miles of river during the 1930's that dramatically changed the course of the river system. Large areas of land were flooded creating Tongland Loch, Earlston Loch, Carsfad Loch, Kendoon Loch and Clatteringshaws Loch. Loch Ken and Loch Doon were considerably extended. The flow of water was controlled by the dams, which could be opened to allow more water through to drive the turbines in the generating stations. Water from Loch Doon, which had previously flowed down the river Doon to Ayr, could be added to the Dee system through a pipeline constructed at Drumjohn.

There are numerous small lochs in the upper stretches of the rivers, set in some of Galloway's most beautiful surroundings, and providing many walks among the hills. Loch Ken provides water sports and there is coarse fishing at many of the lochs and on much of the river.