Banská Štiavnica, the most important mining town in Slovakia, is known for its more than a thousand-year mining history. The wealth hidden underground and the problems with its extraction became the impetus for the construction of water reservoirs. At the time when water reservoirs were built around Banská Štiavnica, they were practically the only water structures in Slovakia.
The creation of the first artificial water reservoirs - tajchs - on the territory of Slovakia dates back to the beginning of the 16th century. At this time, there were already at least five water reservoirs in Štiavnické Hills. The first water reservoir can be found in two locations, in the valley above the centre of Banská Štiavnica and in Hodruša. At the beginning of the 16th century, these small water reservoir served local mines. In the course of the 17th century, other, smaller water reservoirs were built in the vicinity of Banská Štiavnica. The reason for the construction of new water reservoirs were indications of an approaching energy crisis in the mining industry. This crisis involved an intractable problem with underground water, which flooded mines and made it impossible to extract precious metals, gold and silver. The pumping technology of the time only knew pumps that used human and horse power for propulsion. They were mainly horse and various pumping stations. This kind of energy was becoming inefficient and expensive. At the beginning of the 18th century, Matej Kornel Hell (1653 - 1742) built the first pumping machine that could drain all the water from flooded mines. This machine was powered by surface water. However, Hell lacked a sufficient amount of this water to power the machine. That is why he decided to build the largest water reservoir to date - the Great Windshaft at Štiavnické Bane. After Hell, the excellent mathematician, cartographer, surveyor and imperial-royal geometer of Central Slovakian mining towns Samuel Mikovíny (1686 – 1750) took over the construction of water reservoirs and the design of the water management system, who invented the whole ingenious system of building water management systems. Mikovíny came to Štiavnica at the behest of Emperor Karol VI. and took care of the biggest boom in water construction around Banská Štiavnica. During his work, he was able to build, increase, or repair up to thirteen dams of the water reservoirs! In addition to this number, he designed approximately 30 collecting and driving ditches. Mikovíny's successor was Jozef Karol Hell, who completed the construction of four dykes and brought or removed 16 collecting and driving ditches from them. In addition, J. K. Hell was a great designer and inventor of pumping machines. Hell's most significant invention was the water column pumping machine, which made groundwater pumping more efficient and at the same time saved the water accumulated in the water reservoirs. At the end of the 18th century, after Mikovíny and Hellovci, one unique compact water management system remained, which ensured enough surface water to drive traction, pumping machines and treatment equipment, which were constructed exclusively for water propulsion. Of the total number of approximately 60 water reservoirs that were built around Banská Štiavnica for centuries, 26 have survived to this day.
Among the most important water reservoirs are the following:
Rozgrund – The project to build the water reservoir was developed by Samuel Mikovíny. Construction was carried out in 1743-1744. The water reservoir dam has been raised twice and reaches incredible parameters and is among the thinnest earthen dams in the world.
Veľká and Malá Richňava - The water reservoir project was developed by Samuel Mikovíny. Construction was carried out in 1738-1740. In the past, the Richňavské water reservoirs were the most economically important taichs with the most extensive system of ditches. After its construction, Veľká Richňava was the 7th highest earthen dam in the world.
Počúvadliansky water reservoir - The water reservoir project was developed by Jozef Karol Hell. Construction was carried out in 1775-1779. Water reservoir is unique, consisting of 6 dams, built at the junction of the Hron and Ipeľ basins.
Dolný Hodrušský water reservoir - The water reservoir project was developed by Samuel Mikovíny. Construction was carried out in 1743-1744. The water reservoir in Hodrušská Valley has a unique dam with a slim dam profile, which has been repaired several times during its existence.
Veľký Kolpašský water reservoir - The water reservoir project was developed by Samuel Mikovíny. Construction was carried out in 1746. The dyke consists of three dams, which improved the natural offer of the valley and made it possible to build such a high dyke.
Klinger - The water reservoir project was developed by Jozef Schitko. Construction was carried out in 1829-1834. Klinger is the smoothest Banská Štiavnica water reservoir and the only one built in the 19th century.
At the beginning of the construction of water management systems, the driving ditches were laid first, with the lowest possible slope. Driven ditches stretched from the shafts along the contour to empty valleys, to places where it was possible to build a water reservoir dam. In these valleys, many times without the possibility of choosing a dam site, a dam was built to dam the valley, a dam. This dam was high according to the requirements of the operator of the given shafts. The height of the water reservoirs ranged from 3.0 to 32.0 m. When the dam site was difficult to find to fit the shaft, there was a problem in filling the tank. The natural watersheds of individual tajs were small and insufficient for the operation of shafts and towers. Even some taiches were built away from any natural tributary, as they were built just below the saddles at the beginning of the valleys. The solution was found in the supply of springs and rainwater from other valleys of Štiavnické Hills, from the so-called foreign basin. The water in the taich reservoirs was brought about thanks to contour collection ditches that collected water from the surrounding slopes and valleys. The catchment area of just one ditch would be much larger than the entire natural basin of the water reservoir. Some taichas also had several collecting ditches.
The collecting and driving ditches were open channels laid along contours with a minimum slope. Driving ditches had a gentler slope than collecting ditches. The width of the ditches ranged from 0.6 m to 1.0 m and the depth of the ditches ranged from 0.5 m to 1.5 m. The ditch trough had the shape of a trapezoid with a semicircular bottom. The bottom of the ditch and the banks were sealed with high-quality sealing clay or clay. If it was necessary to strengthen the banks of the ditches, stone fortification was used.
The water adit were dug along the ditches, which transferred water from the basin to the basin, beneath the ridges of the hills. Water adit had another meaning. During the winter period, the water flowing underground in the water adit maintained a higher temperature and therefore froze more slowly in the open bed of the ditch.
In total, the Banská Štiavnica water management system consisted of 104 km of collecting ditches and 66 km of drainage ditches, of which the most important drainage ditches were: Hornohodrušský 9,332 m, Dolnohodrušský 8,805 m, Hornokopanický 5,924 m and the most important drainage ditches were: Kolpašský - Rybnícky 6,370 m, Michalšachtovský 5,705 m.
If we evaluate the water management system and the mutual connection of ditches, water reservoirs, and shafts, it is necessary to highlight the precision and ingenuity in the construction of individual systems. The ditches not only perfectly drained the surrounding environment of Štiavnické Hills, but they were very accurately and precisely measured so that they complement each other and use all the captured water ingeniously. The Banská Štiavnica water management system as a whole represents for our country the most important water management work ever built in Slovakia, currently a technical monument of the UNESCO site.
