Final parts of the cave Požiralnik Lokve
Active parts of the Predjama cave system - 2021-04
One of the most important tourist attractions in Slovenia is certainly Predjama Castle. Every visitor is most impressed by the first visit when a fairytale view opens up on a winding road in front of him. The central part of the beautiful veduta is, of course, the castle and many miss the view of a small stream just a little below the Horse Stable. However, this stream is one of the "culprits" that today we can follow one of the longest cave systems in Slovenia.
The water flowing into the ponor has mostly a small flow, so anyone can walk along it to the entrance parts of the ponor, or at least to where the ceiling begins to descend. Up to the first siphon, which is about 150 meters away, the tunnel is mostly about one meter high. In drought it is partly dry, and with a sufficiently large inflow it is completely filled with water. With heavier and longer rains, the flow can increase by over 200 liters per second. Sometimes the ponor is unable to drain such an amount of water and the water therefore accumulates at the entrance of the ponor.
The Lokve ponor was extremely interesting for cave divers, as it leads to unknown parts of the Predjama system. The first diver to enter it in 1964 was the English diver Mike Boone, who managed to swim about 600 meters far through two siphons. He did not count the three shorter siphons, which were later confirmed by cave divers led by Tomo Vrhovec. They started discovering the Lokve Ponor in 1997, and Tomo in the first expedition managed to swim through all the siphons to the big hall, named after the Norik-Sub diving club.
Divers later in numerous expeditions discovered an extensive branching system and measured about 3 kilometers of dry and submerged tunnels. A big problem was the longest siphon Ata Smrk at the end of the Norik-Sub hall, which could have fortunately been avoided by the discovery of the passage Obhodni blatni rov (Bypass Mud Passage). In the final parts, divers were stopped by a flooded siphon which has not yet been swum through, with a length of about 200 meters. Only Tomo dived into it with minimal diving equipment, as the passing to the final parts was already very strenuous, and the trips lasted for 10 hours and more, the longest being almost 16 hours. They were wet all the time of the research and also the lighting was quite scant 25 years ago. More about the research is written in the club’s newsletter Bulletin of the Železničar Caving Club.
Access to the final parts of Lokve was, of course, impossible for usual cavers, but everything turned around in June 2020, when the cavers managed to find a connection from the newly discovered passage Rov Marjana Vilharja towards the lower parts. The turnoff is located in the Karantenija Hall, from which they made it through the abyss of Jernej’s ojej to the sliding mud meander Inquisitor and to the last 20 m level, which descends into the great hall. Already in the first expedition, they inspected the Norik-Sub hall and, above all, determined where the tunnel, according to the divers’ plan, connects with the lower parts.
The following expeditions were mainly aimed at getting to know the cave, inspecting some branches and climbing fireplaces. Ours, especially the photographic one, was similar to the last researching one. We entered the cave a little before ten and through the Rov Marjana Vilharja passage we usually quickly reached the muddy connecting tunnel. We solved the orientation problems in the Norik-Sub Hall, admired the view of the Vodna luknja (Water Hole) and followed the Obhodni blatni rov (Bypass Mud Passage) to the Dvorana Klemen hall.
Shortly before the Hall in front of the meanders, our attention was drawn to a muddy branch, which we followed along a rather steep and completely washed-out slide. According to the plan, the first-timers avoided this part, ending at a small pond and in all likelihood connecting the meander before the final parts. The return was quite difficult, but made easier with a piece of rope as can be seen in the video below.
We finished our tour in the Dvorana Klemen hall, peeked into the Zahodni suhi rov (Dry Eastern Passage) and rather concentrated on taking photos, as the clock was approaching 2 pm, continued to run relentlessly, and before us was the photographic part, the return through the tunnels and the threat of curfew after 10 p.m.
Since last year’s discoveries, the Predjama system has been extended by the researchers to more than 17 kilometers, and with each new visit it is approaching 18. With the rediscovery of the final parts of the Lokve ponor, new possibilities for discoveries have opened up and diving in the final siphon will be easier. If researching luck continues to be on the side of the cavers, we will reach the 20th kilometer in the Predjama system.
This time, Mojca and Boštjan Vrviščar, Yana Bilynets, Primož Gnezda, Borut Jurkovič, Erika Kozamernik, Anja Hajna and Peter Gedei flowed through the final parts of the cave Požiralnik Lokve.