Tajchy
Tajchy (singular: tajch, from German teich) are artificial water reservoirs in the Štiavnica Mountains, in central Slovakia. Most of them were built in order to provide energy for the silver mines of Banská Štiavnica in the 18th century. At their height, tajchy comprised a sophisticated system of 60 reservoirs, connected to each other by more than 100 km of channels and underground tunnels. 24 artificial lakes still exist and serve recreational purposes. Because of their historical value, tajchy were proclaimed by the UNESCO to be a World Heritage Site on December 11, 1993, together with the town of Banská Štiavnica and technical historical monuments in its surroundings.
The region of Banská Štiavnica lacks significant sources of flowing surface water. That is why tajchy were designed to store water derived from precipitation. Channels with the overall length of 72 km diverted water from the rain and melting snow to sixty reservoirs. The whole system could accumulate 7 million m3 of water. The water then flowed through 57 km of channels to water wheels, which powered seven pumps equipped with a pendulum-action system. The pumps removed excess groundwater from mines and the water wheels later also provided energy for mining, processing, metallurgy, and mills.
Banská Štiavnica was an important medieval mining center, producing mostly silver. The first water reservoirs were founded by the local miners in the 15th century. However, the most significant development of tajchy was precipitated by a crisis in the mining industry in the 17th century. The depth of the mines' shafts started to reach below the level of the drainage tunnels. As a result, mines were flooded by ground water. The draining mechanisms of that period were powered by human or animal power, which was too expensive. Due to the prohibitive costs, the Royal Court Chamber in Vienna decided to close the mines in Banská Štiavnica and its surroundings. A mining expert and inventor Jozef Karol Hell challenged the decision, submitting a courageous proposal to rescue mining in his home town. An innovative plan based on the use of tajchy was finally endorsed by Emperor Charles VI.
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