Vízfő Cave

The Orfűi Vízfő Cave is one of Hungary's specially protected caves. It is located in Orfű, within the Danube–Drava National Park. It is one of the five specially protected caves of the Mecsek Mountains. It is the third longest cave in the Mecsek Mountains. It is the source cave of the Vízfő, the most water‑rich and largest water‑collecting source of the mountain. Water flowing out of the cave is the main feeder of the Orfűi lake system. At one time the cave’s water helped supply water to Komló, and later Orfű sometimes received its drinking water from here. The cave’s water‑filled siphon, about 20 m deep, was once the deepest siphon in Hungary. Within the national park it is part of the Western Mecsek Landscape Protection Area, and the area above the cave belongs to the Natura 2000 network.

Description

Next to the Orfűi lake, on the eastern side of the Orfű valley, at the valley floor, in line with the incursion of the Szuadó valley, is the current main entrance, at the foot of a roughly 10 metre high rock wall. This six‑metre long, one‑and‑a‑half metre high, one metre wide, sealed entrance was created by blasting. To the left of this is the other entrance, which was made for drinking‑water extraction. It can also be reached via the Vízfő nature trail, whose second station is at the cave entrance. An information board is placed in front of the entrance. The Vízfő, which is an active karst spring, has its old surface emergence blocked. Not far from the entrance of the Orfűi Vízfő Cave is the historic Spring House, the building called Gomba, which is a pump house built during the construction for extracting drinking water from the cave and was designed by György Csete. The Cave‑Explorers’ spring, also known as the Cave‑Explorers’ source, originates nearby.

The first part of the cave formed in Triassic dolomite, the part farther from the entrance formed in Triassic limestone. The locations of the passages were determined by tectonics and the tectonic fissures were widened by the erosion and corrosion of cold waters to a size walkable by humans according to the cave register sheet made in 2001. In Tibor Parrag's description published in 2003 the role of tectonic preparation is not mentioned and it is described only as a cave formed by dissolution, i.e., of corrosion origin. In the past there were three siphons in the cave, but only the terminal siphon remains, which is 42 m long and was formerly blocked by a concrete wall that prevented its approach. The deepest point is in this siphon. This deepest point is located 21 m below the entrance.

The construction carried out for water extraction determines the cave's condition to a great extent. From the entrance to the "Zuhatagos Hall" a concrete walkway was built; in the "Zuhatagos Hall" a deepened and concreted lake about five–six metres in diameter was created, the cave floor was concreted in several places, several metres thick, the second siphon was bypassed with a culvert and a floodgate was built in front of the third siphon. The current passage runs above the second siphon, about three metres higher. Horizontal extension and fissure‑type passages are characteristic of the cave. The cave can be divided into a branching horizontal active branch and a shorter vertical inactive branch. The cave's highest point is in this vertical branch. The average width of the passages is more than one and a half metres and their height is most often above two metres, but sometimes they are as high as 10 metres. The cave chambers were formed at cross‑directional fractures.

The cave contains many stalactites, among which broken stalactites are common. Such an extent of stalactite formation in caves formed in dolomite is rare. It is one of the most stalactite-rich caves in the mountain range. In front of the terminal siphon, stalactite columns almost one meter in circumference and 1–1.5 meters high have formed. Within it can be observed stalactite flows, stalactite encrustations, hanging stalactites, stalagmites, straw stalactites and helictites as well. In some parts of the cave the walls and the stalactites have a manganese coating. This black crust is up to two centimeters thick in places.

Some species of bats often visit during the breeding season and also use it as a roost. Typical species are the small mouse-eared bat, the large mouse-eared bat, the water bat and the pond bat. It can be visited with the permission of the Danube–Drava National Park Directorate and taking the precipitation conditions into account. The cave can be traversed with basic caving equipment, diving with a breathing apparatus. During the bats' resting period, entry into the cave is not allowed.

The spring's annual water yield is approximately 1.5 million m³ (Parrag 2003), 4 million m³ (cave register sheet 2001), 4,731,971 m³ in 1970 (Parrag 1998) and the amount of water appearing is very variable, the greatest difference being 244 times, or one 244th. The daily water yield can be 100,800 m³ and 414 m³ as well. The spring temperature is 9–12 °C. The catchment area is about 15.3 km², of which roughly 30 % consists of non‑karstic rocks, mainly lower Triassic sandstone and limestone. According to the description published by Tibor Parrag in 2003, the earliest data on the spring's water yield is from 1898 and the spring is not mentioned in the 19th century. The main water‑draining cave of the spring cave is probably the Szuadó‑valley water‑draining cave and the Gilisztás water‑draining cave. In addition to the two caves mentioned above, the presumed cave system of the Orfűi Vízfő cave also certainly includes the Achilles water‑draining cave, the Jószerencsét‑akna cave, the Remény‑zsomboly, the Spirál water‑draining cave and the Trió cave.

The third longest cave in the Mecsek after the Abaligeti cave and the Spirál water‑draining cave.