Mrhal, Lake and cultural monument in Hlincová Hora, Czech Republic

Mrhal is a 15 m deep pond on the Rudolfovský potok, held by a 250 m long earth dam with a clay core and a stone facing on the water side. Its two arms form the Jivenská and Hlincohorská bays, and below the outlet the stream drops over a several-metre waterfall.

The pond was built from 14 August 1555 by Italians as a water reservoir for the Rudolfov silver mining district. In 1611 Passau troops destroyed the dam, leaving it dry for over a century. The city of České Budějovice restored it in 1771 for 21,424 gulden.

The pond was named Mörderteich, "murder pond", after a farmer was killed on the dam shortly after its completion in 1555. The Czech name was originally Mrdal and only became Mrhal in the 19th century.

The lake is now privately owned and managed by a fishing company, so check access rules before visiting. You can find fishing and swimming opportunities there, depending on current conditions and permissions.

When the pond was drained in 2018 for repairs, about 100,000 freshwater mussels of four species were found, including the critically endangered painter's mussel. The Environment Department of the South Bohemian Region noted that such numbers had not been recorded in ponds for about 50 years.