Florian, Maurizio and I headed to lake Radovjića for the final day. The lake was formed back in the sixties when the valley into which a number of small springs emerged was dammed in order to create a reservoir. These springs now emerge at the bottom of the lake. Maurizio spoke to a old local lady who remembered where one of the springs had been before the lake was formed, and she pointed us towards an area of the lake with very steep sides – the spring had emerged from the base of this cliff before the water levels rose and submerged the entrance. As this area was five hundred metres away from the nearest possible entry point, we opted to take the scooters and do a quick scouting survey of the area to see if we could find the entrance to what promised to be virgin cave. The visibility in the lake was fairly crap (~3m) which ensured when the scooter I had borrowed failed after only a couple of minutes, Maurizio crashed into me, not being able to see much beyond the end of the massive cave scooter he was using. Fortunately I was able to hitch a tow with my immobilised machine to continue the dive. Not being able to see much more than Maurizio’s ass for the rest of the journey, I was pleased to reach the other side and dump the scooters. There appeared to be numerous cracks and crevices in the wall but, encouragingly, there also appeared to be a weak surface current that looked like it was being generated by water welling up from below. The first crevice narrowed to nothing but amazingly on only our second attempt (cave diving can be a lengthy process!) we found a passage that appeared to continue on. The visibility in here was also excellent compared to that in the rest of the lake so we were pretty sure we were on to something, and, at the back of this room, at a depth of around 25m, was a small shaft with clear cold water gushing out of it. Florian and I dropped down to check it looked promising and from a small washing machine chamber at the base there appeared to be going passage. With Maurizio not diligently respecting his absence of cave training we headed back out, marked the entrance with a surface marker and headed back across the lake to get some more bottles for a clean attempt at the new passage.
We spent a short surface interval in a beautiful meadow, knotting line and watching fire planes swoop in over the lake, scooping water to drop on a forest fire in a nearby valley. We were reminded of the scuba diver in the film Magnolia and hoped we wouldn’t suffer a similar fate, however, impatient to see some virgin cave we were soon back in the water, skimming across the surface towards our marker. Dropping at the cliff face we tied off in the open water and entered the outer room. This is large and white-walled with pebbles on the floor, very similar to Vucovjića. The shaft is tight and the flow strong enough that I was forced to fully invert myself in order to progress. Laying line through this restriction in a way that wouldn’t present an entanglement hazard whilst battling the flow enraged by my double 18s choking the exit was challenging and certainly wasn’t pretty but once through things settled. Again this entrance restriction constituted the deepest section of the cave and from here on it trended gradually upwards. The nature of the cave also changed dramatically from here on in as well. The ceiling was low but the passage wide, with darkly stained rocky walls. Whilst there was still no silt, the visibility was relatively poor (compared to the other caves we had been diving on this trip) at around 6-8m. Many collapses meant that although the passage itself progressed pretty consistently, the navigable channel zig-zagged from side to side as we picked our way through. We spotted four or five cave shrimp and knowing how localised these species can be and that we were in unchartered territory we were excited to consider the possibility that these may be a new species as yet unknown. The flow, survey effort and restricted nature of the cave meant that progress was pretty slow and having just passed the tightest restriction of the dive, Florian hit turn pressure forcing us to reluctantly thumb the dive. The passage continues however.
As had become the norm for these dives the exit was fast and all to soon we were back out in the murky water of the lake. Having negated to bring any O2 with us on this dive we were faced with the prospect of 30 minutes of back gas deco. Feeling pretty pleased with ourselves this usually boring ordeal passed pretty quickly as we reflected on the dive and we emerged into the gloriously scenic Croatian countryside above, resolute on returning to peak around the next corner as soon as we could.
We headed back to Budapest the following day and managed to squeeze in a couple of dives in the toasty warm geothermal Molnár János cave that runs below the city there, an extremely beautiful cave that has been well documented in the wonderful book Divers of the Dark (http://diversofthedark.com).
You can download the survey of the Radovjića here: Radovjića Survey