Kossuth Cave

Kossuth Cave is located in the Aggtelek Karst within the Aggtelek National Park. It is one of Hungary's specially protected caves. It is also a hydrologically significant cave. Its water flow feeds the Nagy Tohonya spring near Jósvafő. Together with the other caves of the Aggtelek Karst and Slovak Karst, the cave is part of the World Heritage. It is the sixth longest cave of the Aggtelek Karst.

Its existence had been suspected earlier, but it was only explored in 1956, and its current endpoint was reached in 2010 by swimming through a siphon that had proved impassable for decades. The cave and its associated spring are unusual in that the temperature of the karst water is warmer than that of the surrounding karst springs, which is the result of mixing with warmer water coming from the deep karst. On 3 April 2022 a diver researching the cave died in an accident.

Description

The 1,610‑metre‑long cave has a vertical extent of 60 metres, its entrance is at an altitude of 221 metres above sea level, opening on the edge of Jósvafő, directly beside the Tohonya spring. It is poorer in formations than the other caves of the area. The deepest point of the cave is at the bottom of the Desperate siphon at a depth of 33 metres, and its highest point is at the end of the Clay Pool at a height of 28 metres. The closed cave can be visited with permission from the Directorate of Aggtelek National Park.

It is the sixth longest cave of the Aggtelek Karst, after Baradla Cave, Peace Cave, Freedom Cave, Vass Imre Cave and Meteor Cave.

The cave also appears in literature under the names Kossuth Cave (Kordos 1977) and Nagy‑Tohonya‑spring cave system (Bertalan 1976).

Water system

The spring of the cave, the Tohonya spring, also called the Nagy Tohonya spring, has a strongly variable discharge and a water temperature that is higher than usual, which has long interested researchers. According to measurement results, the spring water is colder when the discharge is larger, but still warmer than that of the surrounding karst springs, averaging 14 °C. It is assumed that this is caused either by the mixing of a constant‑flow, warmer water flowing up from the deep karst, or by surface water infiltrating to a depth where it becomes warm.

Occasionally, floods appear in the spring regardless of precipitation, which suggests a complex siphon system. Miklós Gádoros, with detailed measurement series, determined that during such climatic floods the water temperature changes by a few hundredths of a degree, and then, taking into account further factors such as flow speed, water discharge and the propagation of pressure waves, calculated the distance at which the siphon system is located in the still unknown cave section. It was also noted that there may be a correlation between the water discharge changes of the Nagy Tohonya spring and the nearby Lófej spring. The water of the latter disappears not far downstream at the valley floor, and appears in the Nagy Tohonya spring based on the results of a water‑labeling experiment with kitchen salt conducted in 1967. Based on the water‑system survey results, it can be assumed that the currently known Kossuth Cave is only a small part of a still undiscovered larger cave system.

Cave tour

Based on a preliminary written application submitted to the Aggtelek National Park, the cave can be visited in a special cave tour in groups of at least five and at most ten persons. On organized tours anyone can participate who is over 14 years of age or taller than 160 centimeters, however, because water is constantly present in the cave, rubber boots and waterproof clothing, or change‑shoes and change‑clothing, are mandatory. The Aggtelek National Park provides helmets and headlamps for visitors.

After the entrance hall we reach the spacious area called Aula, this room may be connected with the Szelelő-hole above the cave, then a corridor follows, at the bottom of which we see water inlets. In case of flood the water flows out to this point in the main branch of the cave, especially during large floods it also flows beyond these, then it exits to the outside through the entrance hall, joining again with the spring water. A increasingly strong gurgling sound can be heard, this is the Moraj turn, and at the bottom of the fissure the spring water appears, which disappears here and continues its way toward the spring. Continuing onward, the water of the stream forms a deepening lake, which the first explorers descended with a rubber boat, but there was a period when a wooden raft was used, later a tractor cabin helped the cavers in the relatively dry passage, today a wire rope bridge and stepping ladders as well as climbing ladders allow passage without being waist‑deep in water. The lake is followed by two smaller waterfalls, above which trumpets rise upward. (These lead to an upper level about 300 metres long, much richer in dripstones. Visiting this level, however, already requires special preparation.) Leaving the waterfalls, following the water flow we reach a large room with a lake at the bottom, from which the Desperate siphon starts. Here can be seen, in hope of further progress, the chamber blasted in the 1960s, this is the starting point of underwater research, guided tours have been running ever since. From here further passages can be reached only by going down through the siphon, or upward through the narrow section called Agyagkuszoda.