The Stausee Solis ("Solis reservoir") is a reservoir on the Albula river, located between Alvaschein, Stierva and Tiefencastel, in the canton of Graubünden.

It was built in 1986 by the Electric Power Company of Zurich (ewz).

The water in the reservoir is used for energy production further downstream in the power plants Sils and Rothenbrunnen.

Because of the small size of the lake compared with its catchment area sediment aggregation plays an important role.

The dam is located just east of the Solis Viaduct of the Albula Railway.