Velika Karlovica Cave

Velika Karlovica is a karst ponor cave on the western edge of Cerkniško polje. Water from the Cerkniščica, Stržen and most of the lake drains into it. Inside the cave, the water flows onwards into Zelške Caves and forms part of the Ljubljanica basin.
It was discovered in 1927 and eight kilometres have since been explored, although it is only 12 metres deep. The cave is open with controlled access.

I had already photographed the entrance to Velika Karlovica that winter for the KRAS.RE.VITA project, for which some of my photographs will be displayed in the Notranjska Regional Park's new multimedia information centre.

In February the lake was full and the water level still high, with an enormous amount of driftwood at the entrance, so entering the cave would have been difficult even by boat.

In April, our colleague Dr Matej Blatnik, a karst researcher at the Karst Research Institute ZRC SAZU (IZRK), invited us to visit the cave because he wanted to place a water logger in Karlovica Cave as part of his postdoctoral study of Cerkniško polje.
He had not yet been deep inside Velika Karlovica either (beyond the first water), so this visit would serve as reconnaissance to find suitable locations for the logger before he returned with all the equipment.

First, equipped with wetsuits, a camera and a map, we measured the water's conductivity at the entrance and immediately got ourselves a little wet.

The inside of the entrance is interesting, though not especially photogenic, but that is not why I have no photographs from there.
In the past, efforts to regulate flooding on Cerkniško polje led to dams being built in some caves and riverbeds being excavated and altered. A concrete dam at the entrance to Velika Karlovica slows the water draining into the cave. At the bottom of the dam is a concrete pipe through which we entered.
As I watched Ana go through the pipe, I walked backwards and stepped into a hole I had not seen. I scratched my arm while trying to regain my balance, so photography did not even cross my mind for a while.

We also swam through a substantial part of the cave, so on the way to the sump—our objective, a little beyond the aptly named Labyrinth section—I did not even take the camera out of its waterproof protection (which ultimately proved not to be waterproof, though without consequences this time).

While swimming and searching for passages through the Labyrinth to reach the sump, we looked for suitable photographic compositions, and Matej took a few measurements along the way.

In one passage we noticed footprints in the mud and quickly concluded that they belonged to a mammal. With quite a lot of water in between, we ruled out something like a fox, but soon learnt which animal had left them when an otter startled Matej. By the time I had taken the equipment off my back, the otter was gone. At the time the footprints did not seem worth photographing either, which I now regret a little.

On the way back from the sump, we went slightly astray after resting while swimming in one of the Labyrinth passages and then setting off in the wrong direction. We reached the same place as before but thought we were in the next chamber towards the exit. After making two circuits of the Labyrinth and seeing the same washed-in red crate—one of the many enormous pieces of rubbish that find their way into the cave—we realised our mistake, swam back to the resting place without stopping and continued, this time in the right direction.

On the way back, we stopped to take photographs in two places: a beautiful chamber and "by the otters".

Already a little tired—at least the two of us; Matej had probably only just warmed up—we also found an artificial passage on the way back that connects another entrance to the cave: Nova Karlovica.

Exiting through this passage would have shortened our route to Velika Karlovica's main entrance and to the car by several hundred metres, but it required some climbing because the ladder was quite high. It would have been easier to reach at a higher water level. Ana was cold and exhausted without neoprene gloves and I had an injured arm, so after an unsuccessful attempt to leave through Nova Karlovica, we exited Velika Karlovica where we had entered.

In total, we walked and swam a little over four kilometres in the cave, covering about a kilometre and a half in length. We were inside for six hours, including the lengthy process of taking photographs, finding passages and navigating the Labyrinth. We spent about an hour and a half in the water.

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