Minimum Winter Ten-Day Runoff in Rivers of the Lake Sevan Basin

Minimum flow is an important characteristic of the river water regime, since it determines the potential of surface water use. Daily observation data at 12 hydrological stations of the Center for Hydrometeorology and Monitoring of the SNCO of the Ministry of Environment, the Republic of Armenia, and features of long-term fluctuations in air temperature and precipitation at 6 weather stations are used to consider the features of long-term fluctuations in the winter minimum ten-day water flow in the rivers of the Lake Sevan basin. Winter minimum ten-day water flows for the hydrological year, their values with different exceedance probability and variation (variability) coefficients are calculated. A map of the distribution of the modulus of the average minimum winter flow for the decade with the lowest water content (75% exceedance probability) is compiled. Correlation was found between winter minimum ten-day water flows and the January average monthly runoff. It is shown that in sections of the studied rivers there is a predominantly growing trend of winter minimum ten-day water discharges. The same pattern is inherent in changes in the average air temperature and amount of precipitation during the winter period in the studied territory. The obtained results are of great practical importance for hydroecological problems, in particular for the management of aquatic ecosystems, their effective use and protection, determination of environmental flow, risk assessment, forecasting water disasters, protection of river ecosystems from degradation, etc.