Rozkoš Lake, Reservoir in Česká Skalice, Czech Republic.

Rozkoš Lake is a reservoir on the Rozkoš stream near Česká Skalice, impounded by a 412.5 m earth-fill dam 26.4 m high with a 6 m asphalt road on its crest. A 1.7 km Rovenská dam with a 200 m concrete spillway divides it into a smaller northern part and a larger southern part. Its surface reaches 1001 ha.

Plans for a reservoir near Česká Skalice date to 1924, when a scheme with a tunnel feeder from the Metuje and four power stations was proposed. Construction began in 1951, was halted in 1952, resumed in 1964 and was completed in 1969; the feeder from the Úpa was added in 1972.

The reservoir's nickname, "East Bohemian Sea", comes from its size: at 10 km² it is the eighth-largest reservoir in the Czech Republic. Sport fishing is practised here, and the water is a stopover for migratory birds. The dam lies by Česká Skalice, and Ratibořice Castle and the Božena Němcová Museum are nearby.

Autokemp Rozkoš operates year-round with accommodation for over 3,000 people, offering tent and cabin rentals, boat rentals, restaurants, playgrounds, and fishing permits available from the local municipal office in Česká Skalice.

The main dam has no safety spillway at all; that role is played by a weir on the Úpa at Zlíč, whose steel flap 3.15 m high keeps the reservoir from overfilling. The 200 m concrete spillway sits on the separate Rovenská dam, which divides the lake in two.