Margaryan et al. (2025) Glacier regime of the Drakhtik River (Lake Sevan basin) in the conditions of climate change

Identification

• Journal: Visnyk of V N Karazin Kharkiv National University series Geology Geography Ecology
• Year: 2025
• Date: 2025-12-01
• Authors: V. Margaryan, Svitlana Reshetchenko, Sviatoslav Dmitriiev
• DOI: 10.26565/2410-7360-2025-63-21

Research Groups

• Department of Physical Geography and Hydrometeorology, Yerevan State University, Yerevan, Armenia
• Department of Physical Geography and Cartography, V.N. Karazin Kharkiv National University, Kharkiv, Ukraine

Short Summary

This study investigates the spatio-temporal changes in the ice regime of the Drakhtik River (Lake Sevan basin) from 1956/57 to 2024/25, revealing a significant reduction in ice cover duration and maximum ice thickness due to rising air temperatures.

Objective

• To investigate the ice regime of the Drakhtik River (Lake Sevan basin) and to identify, analyze, and evaluate the patterns of temporal distribution and changes in ice phenomena under climate change conditions.

Study Configuration

• Spatial Scale: Drakhtik River, Lake Sevan basin, Armenia, specifically at a hydrological post near the Drakhtik settlement. The catchment area is 39.2 square kilometers, with an average altitude of 2270 meters.
• Temporal Scale: Long-term meteorological, climatic, and hydrological observations spanning from 1956–1957 to 2024–2025. Specific hydrological post data is available since 1967, climatic characteristics from 2011/12–2024/25, and detailed ice regime characteristics from 1974/75–2024/2025.

Methodology and Data

• Models used: Methods of hydrological analogy, interpolation, extrapolation, mapping, and standard statistical analysis were employed. No specific named hydrological models (e.g., ISBA, mHM) were mentioned.
• Data sources: Observational data on the water and ice regime of the Drakhtik River, as well as air and water temperature and atmospheric precipitation. Data was obtained from the Center for Hydrometeorology and Monitoring of the Ministry of Environment of the Republic of Armenia (for the Drakhtik River near Drakhtik settlement) and the Sevan weather station. Fieldwork results were also utilized.

Main Results

• The temporal analysis of ice regime characteristics indicates a tendency toward a reduction in the duration and intensity of ice cover.
• A decrease in both the duration of ice phenomena and the period of stable ice cover has been recorded.
• Freeze-up dates tend to shift to later periods, while ice breakup dates occur earlier, resulting in a shorter ice-cover duration.
• The maximum ice thickness shows a consistent decreasing trend, with a linear trend coefficient of -3.4 centimeters per decade. The average maximum ice thickness is 18 centimeters, with a recorded maximum of 37 centimeters on 15 February 1976.
• The thickness of the snow cover on the ice also has a downward trend, with a maximum recorded thickness of 23-24 centimeters.
• The average duration of freezing (from the appearance of ice phenomena to the establishment of ice cover) on the Drakhtik River is 19 days, fluctuating from 2 to 78 days.
• Continuous freeze-up forms annually, lasting on average about 75 days, with fluctuations between 0 and 137 days.
• No spring or autumn ice drifts, slush drifts, ice jams, or ice dams were observed on the river.
• At the Sevan weather station, an increase in average air temperature during the cold period (November–March) was recorded, with a linear trend coefficient of +0.27 degrees Celsius per decade.
• The sum of positive temperatures during the cold period shows a trend of +10.1 degrees Celsius per decade.
• The total amount of precipitation shows a trend of +10.4 millimeters per decade, and the average snow depth in March shows a trend of +0.27 centimeters per decade.
• The average winter runoff of the Drakhtik River shows an increasing trend.
• Water level values in the Drakhtik River for the period November–March fluctuate within a small range, from 38 to 43 centimeters.
• Water flow rate values for the same period range from 0.074 to 0.22 cubic meters per second, with the lowest monthly value (0.074 cubic meters per second) recorded in January.

Contributions

• This study presents the first comprehensive investigation of ice phenomena on the Drakhtik River, addressing a poorly studied region within Armenia.
• It quantifies the significant impact of contemporary climate change, specifically increased winter air temperatures, on the ice regime of the Drakhtik River over a long-term observation period (approximately 50 years).
• The research provides detailed spatio-temporal characteristics and trends of key ice phenomena parameters, including duration, timing of freeze-up and breakup, and ice thickness, which are crucial for regional hydrological understanding and management.
• It highlights the observed shifts towards later freeze-up dates, earlier breakup dates, and a reduction in both ice cover duration and maximum ice thickness, contributing to the broader understanding of cryospheric responses to climate change.

Funding

The study was financially supported by the Science Committee of the Republic of Armenia under the scientific project 24WS-1E035.

Citation

@article{Margaryan2025Glacier,
  author = {Margaryan, V. and Reshetchenko, Svitlana and Dmitriiev, Sviatoslav},
  title = {Glacier regime of the Drakhtik River (Lake Sevan basin) in the conditions of climate change},
  journal = {Visnyk of V N Karazin Kharkiv National University series Geology Geography Ecology},
  year = {2025},
  doi = {10.26565/2410-7360-2025-63-21},
  url = {https://doi.org/10.26565/2410-7360-2025-63-21}
}