by Alessandra Ressa
On Sunday, August 11, a renewed quest to unravel the mysteries of the Timavo River’s subterranean course will commence in the Trebiciano cave in Trieste. The Adriatic Speleological Society of Trieste, in partnership with the Fédération Française d’Études et de Sports Sous-marins (FFESMM) from Marseille, is set to embark on the ninth mission of its ongoing Timavo System Exploration (TSE).
The TSE mission, which began in 2013, aims to map the elusive underground path of the Timavo River. This year’s exploration follows significant breakthroughs achieved in 2022, including the successful bypass of the Trebiciano abyss’s exit siphon and the discovery of the Maucci Cave. Despite a forced pause last summer due to severe weather conditions, the mission’s goals remain unchanged, merely rescheduled.
This year, the French speleosub team, supported by the SAS, will tackle two primary objectives. The first involves returning to the Maucci Cave, also known as the Cave of the Thousand Sherpas. The team will retrace the Trebiciano exit siphon to continue exploring the underground river’s path, which stretches toward the Luftloch cave. Luftloch, whose bottom was first reached by SAS explorers in March, lies approximately 400 meters away—a substantial distance in the challenging conditions of subterranean water.
The second goal is to advance the exploration of the inflowing siphon path within Trebiciano. Using automated topographic tools, the team plans to map this challenging terrain. The aim is to overcome the visibility issues posed by the Timavo’s murky waters and gather crucial data on the water route extending from Lake Timeus, through Lake Boegan, to newly discovered air-filled chambers.
Additionally, a chemical and bacteriological sampling, commissioned by the University of Trieste, will be conducted. This will involve collecting sand and water samples from the Maucci Cave, complementing previous sampling efforts in Trebiciano and Luftloch.
The TSE mission’s significance extends beyond exploration. It represents an opportunity to enhance the understanding of these unique caves and potentially create a unified Trebiciano-Maucci-Luftloch system. “TSE is not just an important exploratory endeavor,” said Marco Restaino, president of the Adriatic Speleological Society of Trieste. “It’s also a moment of unity for the local speleological community. Our successes are the result of collaborative effort.”
The 2024 expedition will feature seven French speleosubs, with five diving and two providing support from the abyss’s bottom. They will be joined by a substantial team from the Adriatic Speleological Society, managing logistics and supporting the mission. Additional assistance will come from speleologists from various Italian and Slovenian societies, who will handle the transport of heavy equipment required for deep dives.
The mission will be supported by a comprehensive logistical setup, including dual communication systems and daily operational support. The week-long exploration will feature daily double dives, underscoring the commitment of SAS and FFESSM to their goals. The mission will conclude on August 17 with material recovery, a ceremony unveiling a commemorative plaque for the 2022 expedition, and a traditional dinner. The French team will depart for Marseille on August 18.
The results of the TSE 2024 mission will be exclusively revealed at a conference titled “Timavo and Secret Caves,” organized by the Adriatic Speleological Society in collaboration with the Municipality of Trieste. The conference will be held on September 21 at the Sala Luttazzi, Magazzino 26, in Trieste’s evocative Old Port.
