The Sous valley dam was built in 1915 on the Cerna Desna river. Its dam is sprinkled, 21 meters high and 364 meters long. The water level covers an area of about 86 hectares. It was named after the settlement of Sous, part of which is now located below the dam.

In 1974, the dam was transformed into a drinking water reservoir for the Jablonec, Tanvald and Zeleznobrod regions. Swimming and fishing are therefore prohibited here and the surroundings are strictly protected.

The repaired Sousska road leads around Sousa, along which passenger cars can get through Smedava to Bily Potok and Hejnice on the other side of the mountains, but only during the summer season from May to October. The road is closed in winter.