by Alessandra Ressa
The pouring rains that hit Trieste and Slovenia in the past two weeks have resulted in an exceptional flow of the underground river Timavo. Consequently, the Trebiciano Abyss is currently flooded, with water levels reaching approximately 40 meters above average for this time of year.
Large areas of sand dunes at the bottom of the Abyss in what is known as the Lindner cave have been carried away by tumultuous waters, thus revealing a chasm, and possibly others, of over 20 square meters not far from where the last metal ladder down the cave touches the bottom of the abyss. Brave speleologists of Trieste’s Società Adriatica di Speleologia have been monitoring the flow, water levels and water visibility on a daily basis, climbing up and down the almost 400 vertical meters separating the Carso surface from the bottom of the cave and carrying special instruments for measurements. The updates have been passed on to the French exploration mission TSE which was meant to start on August 12. However, after a careful evaluation of the dangerous underground conditions, the team of French cave divers of the National Cave Diving Committee FFESSM has taken the painful decision today to cancel the 2023 expedition in the Timavo river.
“Of course we are disappointed after weeks of arrangements – president of Società Adriatica di Speleologia Marco Restaino, which for years has been giving support to the French explorers, comments – but we completely understand the decision. We have been in contact with the French divers on a daily basis to update them on the situation, which has only slightly improved but is far from being ideal. It is an exceptional flood, – Restaino continues – I have been monitoring the Timavo river flows and floods for 25 years and never before have I witnessed such overflow at the beginning of August, reaching at the moment 150 cubic meters per second where the river leaves the surface to enter its underground path in Skocjan, Slovenia. This time last year, the amount of water flowing in the same spot was one half cubic meter per second”.
Although the situation appears to be slightly improving day by day, with water levels slowly decreasing, the river’s persisting strong and unpredictable currents, sudden whirlpools and muddy waters with little or no visibility, would have put at risk the security of divers for this year’s exploration mission of the Timavo river. The 8th Timavo System Exploration expedition, which in the past few years has led to the discovery of two large caves along the underground river connected to the Trebiciano Abyss by narrow underwater passages will be moved to summer 2024. It is with great disappointment that the French cave divers involved in the exploration, who had great expectations this year to reach yet another huge cave along the underwater path explored so far, have given up the trip.
All Trieste speleologists of Società Adriatica, who have been logistically supporting the French explorations of Timavo so far, are naturally disappointed as well, although the news to call off the mission did not come as a surprise. Two of the five divers had already given up in the last few days because of the dangerous conditions of the river. Last year, the French team was able to discover a new cave thanks to the favorable conditions of the river; the ongoing drought had greatly reduced the water level and currents, while visibility was excellent, approximately 7 to 10 meters.
This year, visibility has been estimated to be 10 centimeters…. As one humorous speleologist pointed out, “just put some cardboard in your mask and you’ll get the same result”. Cave diving is probably one of the most dangerous activities on earth, and what motivates the French divers, as they very well explain in the documentary Timavo System Exploration, is the hunger for new discoveries, the thrill of being the first human to set foot where nobody else has ever been before. But wise evaluation of risks has to be part of the job, and the divers have doubtlessly taken the best decision for their own safety, and for the future of Timavo explorations.
