Underground waters in Slovak karst

In the Slovak karst the limestones of the Middle Triassic Period are the most water-bearing strata. The impermeable bedrock is made by clayey-shale rock of the Lower Triassic Period age. Both rocks are a part of the Silica Nappe. The most important source of the underground waters has precipitation, which infiltrate into the carbonates without a surface outflowing. Of some importance to the infiltration of the surface waters into the carbonates are the allochthonous surface streams. Those recharge the underground waters by percolation ponors usually. The movement of precipitation waters, infiltrated into the carbonate massif, is influenced above all by the tectonic transgression of the carbonate massif and by its local karstification. The position of the intercourse of the Middle Triassic carbonate rocks and the barrier of Lower Triassic shale substrata against the local erosion basis is important too. The interval between an infiltration and an outflowing depends above all on the climatic characteristic of a period. It is short (4-6 days) during very moist periods and becomes longer proportionally with the duration of the period without precipitation.

Structures in the freatic zone


The Slovak Karst territory is subdivided to series of the hydrogeologic structures. In the hydrogeologic structures, where the contact of both rocks is on the local erosion level, all the karstic water outflows are concentrated on this level into surface springs (for example system of the west part of the Horny vrch Plateau). In the areas, where the synclinal formation causes the contact of limestones and shales deeper than erosion level, the underground waters differentiate into the waters outflowing on the local erosion level and waters entering deep-reaching circulation in karstic fissures (for example structure of the Plesivska Plateau, of the Velka skala Rock, the Ardovska system). The freatic zone joined separate plateaus into few large hydrologic systems. Of them the most important are structure:

The underground river Styx in the Domica Cave (66kB).

Hydrologic systems in the vadose zone


The large underground systems are attached on the vadose zone of the hydrologic structures. The system of the underground river Styx (on picture) starts in the ponor Certova diera Cave, continues by the Domica Cave and crosses a state border to Baradla Cave. Neighbouring underground system of the Brezovsky Brook put the Milada Cave, the Bezodna Chasm, the Na kecovskych lukach Cave and a few small caves together. The cave system of the Silicka ladnica Ice Cave and Gombasecka Cave is created on the underground stream of the Cierny Brook. Next systems on the Silicka Plateau are the Ardovska Cave hydrologic system, system sprung by the Krasnohorska Cave and system of the Sokolia skala Spring with the Majkova Cave.

The lake in the Drienovska Cave (54kB).

The underground hydrologic system of the Plesivecka Plateau springs in the Zugo Cave on the west slope of the plateau, in the Brzotinska Cave on east end of plateau and in the Vidova spring with unknown underground passages on south slope of the plateau.

The Hrhov Spring is with most force yield from the Horny vrch Plateau. The Hrusovska Cave with Evetes Spring ends a small hydrologic system between the Silicka Plateau and Horny Vrch Plateau. On Jasovska Plateau two systems are explored - the Drienovska Cave (on picture) and Cave System of the Skalisty Brook with the Kunia Abyss. The unknown underground passages of the large system in a middle of the Jasovska Plateau come to end in the Gajdova stolna Spring.

Utility of the karstic waters


The underground karstic water of shallow circulation, as well as karstic-fissure underground waters in freatic zone are of Calcium bicarbonate type with an average mineralization 460-490mg/l. Waters of deeper circulation have an increased temperature (up to 18oC). Even the utilization of the underground waters of the Slovak Karst of our days justifies to mark out the territory as an important from the water economy point of view. Especially higher protection is needed for the underground waters of shallow circulation. A quality of the underground waters in the Slovak karst is so high that numerous springs are sources of the water supplies without some cleaning. Waters from vadose zone are used for water pipes of villages (for example Haj, Jasov, Silica, Hrhov, ...), the freatic zone puts a water into town and city pipes (Roznava, Turna, Kosice). Unfortunately, this fact makes an exploration of cave systems difficult. Numerous prohibitions and attitude of the bureaucrats stop activities of the cavers.

SLOVAKIA CAVE SERVER prepared by Eduard Kladiva (Old Cave Dog) from Speleoclub CASSOVIA . Please send all comments, notes and corrections on e-mail kladiva@saske.sk.