Assessment of the current state of the hydrochemical regime and water-environmental problems of the basin of the Gavaraget River flowing into Lake Sevan

The results of studies of the current hydro-chemical state and water-ecological problems of the Gavaraget River basin, which flows into Lake Sevan from the north-west, are presented. Extreme water discharge, ten-day flow, ecological output have been determined, water-ecological features have been identified, long-term dynamics of the main indicators characterizing the ecological state of the Gavaraget River, spatial-temporal changes in winter and summer-autumn ten-day flow have been shown, the hydro-chemical state has been presented, the main water-ecological problems of this basin and ways to solve them were proposed, the physical and chemical state of Gavaraget water was clarified in accordance with the standards and requirements for water quality, and the level of risk was indicated. It has been clarified that the annual runoff in the basin basically follows the general features of the annual precipitation regime: the minimum amount falls in winter, and the maximum in spring. It is shown that Gavaraget is one of the most polluted rivers in the Lake Sevan basin. It was revealed that it is mainly contaminated with untreated domestic wastewater and agricultural return water. It was found that as the impact of anthropogenic load increases, river water pollution increases from the source to the mouth of the river. The water quality in the upper part of Gavaraget (0.5 km upstream from the village of Tsaghkashen) is excellently characterized as “excellent” (I) and “good” (II), in the lower part (at the river mouth) with “moderate” (III) and “unsatisfactory” (IV) class. The research results can be useful in solving geo-ecological problems, managing aquatic ecosystems, determining ecological flow, assessing risks, predicting water disasters, protecting river ecosystems from degradation, etc.