A tajch, a water management achievement near Slovak mines.

Banská Štiavnica's revolutionary water-management systems

Samuel Mikovíni (1686 – 1750) was a mathematician, cartographer, surveyor and royal geometer of central Slovak mining towns, who made a major contribution to improving the functionality of the old tajchs reservoirs in Slovakia. He was responsible for finalizing the complex mining water-management system that ensured the operation of mining enterprises.

Počúvadlo Water Reservoir is one of the most famous tajchs. It is located under Sitno Hill, the highest peak in the Štiavnica Mountains. – © CBS

Maintaining the reservoirs developed by Hell, Mikovíni renewed and elevated their dams, designing and building new tajchs. The hilly terrain was incredibly complex, but he managed to establish dams for the reservoirs as well as tens of kilometres of channels that connected the tajchs and supplied water to drive the mining equipment.

Thanks to both gravity and elaborate layout, the channels filled the tajchs with rainwater. A system of water tunnels connected the tajchs, enabling the miners to direct the water wherever it was needed. This ingenious water-management system solved the energy problem for Štiavnica's mining industry right up until the beginning of the 20th century.

Ottergrund tajch (lake) is the highest reservoir and provides wonderful views on Banská Štiavnica. – © Jan Petrik

More than 60 water reservoirs were built around Banská Štiavnica. They were able to hold up to seven million cubic metres of water, and used to drive mining, processing and smelting equipment but also to operate the ore mills. Some of the tajchs were used as a source of drinking water, others later changed to fish ponds. Today, many of them are used for recreation.