Tba Ortskali

Tba Ortskali, often simply referred to as Ortskali Lake, is a remarkable and unique body of water located not on the surface, but within the depths of the famous New Athos Cave system in Abkhazia, Georgia. This karst lake is situated in the Anakopia Hall (also known as the Anakopia Abyss or Tbilisi Hall), one of the major chambers of this extensive cave network. Its existence is intrinsically tied to the karst geology of the Iverian Mountain. Fed by underground streams percolating through the limestone, Ortskali is characterized by its stable, cool temperatures and high water clarity. The lake is a significant feature for tourism within the cave, often experienced by visitors via boat tours, offering a glimpse into the subterranean hydrological wonders of the region. Its primary significance lies in its unique geological setting and its role as a highlight within one of the world’s large cave systems, rather than typical surface lake uses like large-scale fishing or water supply.

Identification and Location:

• Name of the Lake: Ortskali Lake (Georgian: ორწყლის ტბა – Ortsk’lis Tba), sometimes referred to as part of the New Athos Cave lake system. “Tba” means lake in Georgian. It may also be referred to by Russian names associated with the cave hall it occupies.
• Location:
  • Country/Region: Abkhazia, Georgia. (Note: The political status of Abkhazia is disputed).
  • Specific Location: Inside the New Athos Cave (also known as Anakopia Cave), near the town of New Athos (Akhali Atoni), situated on the slopes of the Iverian Mountain. It is located within the Anakopia Hall/Abyss chamber of the cave.
  • Coordinates: Approximate coordinates for the New Athos Cave entrance are around 43.090∘N,40.815∘E. The lake lies within this cave system.
  • Relationship to other bodies of water: It is part of the complex subterranean hydrological system of the New Athos Cave, fed by underground streams and potentially connected via karst conduits to other underground water bodies and possibly, eventually, the Black Sea located a few kilometers away.

Physical Characteristics:

• Surface Area: Relatively small, estimated to be around $0.05$ km2 (5 hectares) or potentially smaller, depending on the exact definition and water levels within the cave hall.
• Maximum Depth: Believed to reach depths up to 50 meters. It’s considered a relatively deep lake for its surface area, occupying a significant portion of the cave abyss.
• Average Depth: Not generally specified.
• Volume: Not generally specified.
• Elevation: The lake surface lies within the cave system, estimated to be roughly 100-150 meters below the cave entrance, placing it perhaps around 220-240 meters above sea level.
• Shoreline Length: Irregular, defined by the cave walls of the Anakopia Hall. Not a conventional shoreline.
• Water Source(s): Primarily underground streams and percolation of water through the karst (limestone) rock massif.
• Outlet(s) (if any): Subterranean outlets through the karst system; does not have a surface river outlet.
• Water Type: Freshwater.
• Basin Geology: Karst lake formed within a limestone cave system (New Athos Cave) developed in the Iverian Mountain massif.

Ecological Information:

• Flora (Plant Life): Due to the lack of significant light penetration into the cave hall, aquatic vegetation is likely minimal to non-existent. The “shoreline” consists of cave rock formations.
• Fauna (Animal Life): Natural fauna is likely limited to species adapted to cave environments (stygofauna), such as certain crustaceans or other invertebrates. Fish, such as trout, may have been introduced historically for visitor interest, but substantial natural fish populations are unlikely.
• Trophic Level: Likely Oligotrophic (nutrient-poor) due to the filtered nature of its karst water sources and limited organic input.
• Water Clarity: Generally very high, typical of karst water bodies where water is filtered through limestone.
• Water Temperature: Stable and cool year-round, typically around 10−13∘C.
• pH Levels: Likely neutral to slightly alkaline, characteristic of water in contact with limestone.
• Dissolved Oxygen Levels: Expected to be sufficient to support limited aquatic life, maintained by inflow and water movement.
• Unique Ecological Features: Its subterranean environment is the primary unique feature, potentially hosting specialized cave-adapted organisms.
• Conservation Status: The lake is inherently protected as part of the New Athos Cave tourist site and natural monument. Conservation efforts are tied to the overall management and preservation of the cave system.
• Invasive Species: Any introduced fish could potentially be considered non-native.

Human Interaction and Significance:

• Historical Significance: Tied to the exploration and development of the New Athos Cave, which was discovered in 1961 and opened for tourism in 1975. The lake became known as one of the cave’s most impressive natural features.
• Current Uses: Primarily tourism (boat tours on the lake are a common part of the cave visit), speleological and hydrological research. It is not used as a source for drinking water, irrigation, power generation, or commercial fishing.
• Environmental Issues: Potential impacts related to tourism include artificial lighting, disturbance from boats, and the potential introduction of pollutants. Maintaining the natural state of the cave’s hydrological system is crucial.
• Management and Conservation Efforts: Managed by the authorities overseeing the New Athos Cave complex. Efforts focus on balancing tourism with the preservation of the sensitive cave environment.
• Local Communities: The New Athos Cave, including Ortskali Lake, is a major tourist attraction and a significant contributor to the local economy of New Athos.

Interesting or Unique Facts:

• The lake’s location entirely within one of the largest and most famous cave systems (New Athos Cave) is its most defining characteristic.
• It is often cited as one of the highlights of the tourist route through the New Athos Cave, with boat excursions offered on its surface.
• The lake exists within a massive chamber (Anakopia Hall/Abyss), adding to the dramatic subterranean scenery.
• It represents a visible part of a complex and largely hidden underground water network typical of karst regions.