An interesting technical site in the Šumava mountains (Bohemian Forest) is the hydroengineering structure below the Černé Jezero (Black Lake). There is the first pumped water storage in the Czech Republic.

The system uses the nature lake and the artificial water reservoir for the production of electricity. It was built at the end of the 1920's. The dam of the reservoir, which dammed the Černý Potok (Black Stream) running from the Černé Jezero, is 7 m high and 64 m long. The reservoir contains 23,000 cubic metres of water. The hydroelectric power station is the technical monument in present.

The dam can be found on the field path, which turns-off right from the road from the village Špičák to the town Nýrsko (about 3 km). Another way is possible from the railway station Hojsova Stráž-Brčálník (about 1 km).