The oldest Czech water reservoir built in 1894 - 1896 on the Ušovice brook. Masonry gravitation dam is 19 m high and 152 m long in the crest.
The water surface has the area 4,3 ha. The reservoir serves as storage of water for Mariánské lázně and therefore the entrance for public to the proximity of the reservoir is forbidden. (Zone of hygienic protection of 1st degree).