Participants: Florian, Wilke, Heinke, Mark, Anke, Tobias, Ben, Ivo
This time we have decided to measure a cave in Slovenia because we were so fascinated by the karst landscape and of course by the caves in the Mediterranean area. Florian had suggested the cave Bilpa as the destination for our project due to a contact with Slovenian cave divers and a scouting tour in the winter with Ben.
On the left bank of the river Kolpa in a valley near the Croatian border and the municipality Kostel are several karst caves. The Slovenian poly-historian Valvasor described in detail the steep rock face above the caves in the form of a human and devil head and called it "Wall of Echoes". The cave consists of passages which are located on different levels; the lowest is still active. The entrance to the dry cave is located in the wall 30 meters above the valley.
Marc and Heinke started their journey early in the morning from the North after they had checked whether they had their snorkel and SMB with them. That is one of the rules, if you want to dive in Slovenian caves (no one knows why, but rules are rules). Our "Southerners" still slept in their beds. Ivo came directly from Prague.
In the evening we all arrived at our apartment; we could place our equipment in a large garage and had a look at the cave pool which was about 300m down the road. We made the first plans for the next day.
Florian guided us into the cave to see what difficulties we could expect during the transportation of the RBs and the other equipment and also to decide which teams were needed to accomplish the other tasks.
We had an old map from 1999. The line situation in the cave is good (Hungarian cave divers who dive the cave apparently regularly laid the line). The visibility was poor. We discovered side passages, which were not shown on the map.
After a short straight section starting from the cave pool, the cave turns left into the first sump. Then you come into a small semi-dry area with a water depth up to 1.5 meters and continue diving through the 2nd sump. Both sumps are max.17 meters deep. The main line ended in a huge dry hall with 2 lakes. So we had to take off our gear, grab our backup lights and start rock climbing.
After we swum through the first lake with a small sandy island at the end, we had to climb through a very narrow canyon and a little stony "riverbed" to reach the 2nd lake. We also swum through this 2nd lake to get to another sandy island which we called 'Banana Island’ after Ivo ate a banana there which he had taken with him as a power snack. Banana Island was supposed to be the starting point for the RB-divers to explore sump 3 and whatever there may be further down in this cave. After about 3 hours we all came back out of the cave and started to prepare our equipment for the next day.
The dry tubes had to be rigged. We also equipped our helmets with lamps and labeled clothespins for the measurement points. Team members prepared their RBs. Wilke went back on the road because he had left the base plate of the counter lung at home.
Igor and Martin, our Slovenian contacts, visited us in the evening and recommended some other caves that we should look at in the next few days.
This day was characterised by lifting, carrying, pushing, swearing, climbing and in between short exhausted rests. Three RBs and many stages had to be brought to "Banana Island". Down to the first lake it went reasonably well. The rocks were very sharp and wet. The greatest difficulty was to carry the RBs through the canyon, which was at some points so narrow that one could just squeeze themselves through.
However, all together we have made it so that after a brief pause, Tobias, Florian and Marc could get ready for the exploration of sump 3. Once they descended the others climbed back through the canyon. Soon after we were called back. Marc's main lamp had failed. Therefore he had to go back with the rest of us.
After 7 hours we saw again daylight. We had already put some clothespins on the cave line but postponed the measurements of sump 1 and 2 to the next day. As we just started to get ready to meet the push-team they surfaced in the cave pool.
They had dived sump 3, however in sump 4 it was not clear how the cave continues. Sump 3 ends after about 300 meters and a max. depth of 42 meters on the surface in a canel-like passage. It’s impossibe to exit this passage. It was necessary to lay a new line, which we postponed to the next day. After all they were already in the cave for more than 10 hours and therefore slightly exhausted.
While the push-team (this time with Marc) explored sump 4, Ivo, Wilke and Heinke began to set measurement points and wrote down depth, azimuth and the four distances (pings) to the wall. Anke and Ben were supposed to measure the distances between the measurement points, but since Ben had lost both of his masks they went to Ljubljana to get new ones. Therefore the first team also took some of the distance measurements. Unfortunately Heinke’s dry suit flooded so this dive had to be terminated early.
The push-team reached sump 4 after about 100 meters and a maximum depth of 60 meters. Unfortunately, they needed to turn because of their gas mixes. They have repaired the line and laid some new line. The total length at this point is a bit more than 1000 meters.
While the push-team measured sump 3 Ivo, Heinke and Wilke took measurements in the side passages. After about 7 hours both teams surfaced being happy and very hungry.
It rained and the son of our landlord was waiting for us. He asked us whether everything was ok and whether the cave had already responded to the water. He told us that it had rained heavily in the hinterland and that he hoped that the flow in the cave would not be too strong ...
Still thinking possitive - because it had already rained the day we arrived - we entered he measurement data into the computer
It has been raining throughout the night. The river in front of the apartment was not blue any longer - it was brown. Water shot out of the cave, so that it formed a ’mushroom’ in the cave pool. The water level has risen clearly visible by about 1,5 meters – no way to dive in this cave. Three RBs, many stages, two dry tubes and various other equipment - partly not secured - were still in the cave and we did not know what happened to it.
The rain stopped at 10:30 o’clock; the sun was shining, but the water level was still rising. We looked at some "dry caves" in the valley - there was also water shooting out of some of them. Partly the water pressed through the asphalt road.
How is it, once "everything is falling apart"? First of all, the whole team seemed paralyzed; over and over again a small group went to cave pool, looked lost at the water, calculated the water level and realized that one could not change anything. We worried about how to proceed and started planning to come back on the next weekends ...
We decided to remain on site. Locals told us that within 2-3 days everything should calm down. So we still had time ....
In the afternoon Igor and Sebastian came to visit us. They showed us a huge map of a well-known cave of whose dry area they already had measured up to 4000m. We had a couple of beers with them and enjoyed the nice evening together. They told us about the Slovenian ’Mexico Cave’. So we decided to dive this cave the next day and to make some nice photos.
Cheerfully we headed towards the Slovenian ’Mexico Cave’ (Suhadolca). It was supposed to be max. 15 meters deep with good visibility and many stalactites and stalagmites.
Getting there was rather difficult. We had to carry our D12 through the woods on a steep trail down to the river and then crawl into a long grotto. Then we needed to walk through a longer passage which was only 1.5 meters deep with big rocks. Eventually the actual cave started – however with zero visibility! We decided to turn back - we all met in a small semi-dry area and took some photos. Then we carried our gear up the mountain again. Wilke drove back home that afternoon.
The plan was either to rescue our equipment out of the cave, or to go rafting. But ... with little flow we were able to dive the cave. The three RBs (at least a situation where their weight makes sense) were still lying on Banana Island (just a little deeper down in the water). The stages were spread out in the rear part of the second lake (here we understood the sense of taking our snorkels into the cave - we could snorkel in the lake and search for the stages:-)). We fould one stage right at the entrance of the cave. It was probably flushed through the canyon to the entrance. The dry tubes (unfortunately open) were also there, including various small equipment parts. We ended up finding everything but one stage of Florian, even the mask of Ben and the helmet of Heinke which got stuck 2 meters high in the dry part between two rocks.
Everywhere there was mud and in the canyon the current was so strong that it tore us the stages out of our hands and jammed them between the rocks. We had to be careful that we were not pressed under the rocks by the flow. However we were able to get everything out of the cave without any damage. On the way out one dry tube flooded in the first sump. We could salvage it during the next dive. Anke and Ben could also take the missing data.
Exhausted but happy we all had dinner together. The next day we drove back home with many new experiences and memories of a really nice project!
PS: The missing stage was found by the Slovenian cave rescue team the following weekend. They had carried out a rescue training in the Bilpa.
Maps can be found below