Existing high-resolution reconstructions of hydroclimate variability in the Caucasus are lacking tree-ring data from Armenian Plateau, the most continental part of the region. Our research presents the first dendrochronological investigation in Armenia. Juniper and oak tree-ring width chronologies were constructed, the longest spanning the last 140 years. The positive influence of spring–summer precipitation and the negative influence of temperature suggest drought stress at the investigated sites. Moving correlation analysis indicated a significant change over time in the sensitivity of investigated trees to climatic variability; juniper, previously sensitive to both temperature and precipitation, has shown especially strong precipitation signals in the recent decades since the local climate has turned more arid. Ongoing climate change increases drought stress in juniper, which may have further consequences on semiarid ecosystems. Our results reveal multiannual droughts recorded by tree rings, emerging in most parts of the Black Sea–Caspian Sea region.

This article discusses the impact of artificial lowering of lake water level on water ecosystems using the case study of Lake Sevan. Numerous rivers, lakes and, in general, water bodies have undergone considerable changes under the impact of the economic activity of man. As a result, hydrometrical, hydrological, biological, ecological conditions as well as the morphometrical elements of these bodies have been destroyed. Lake Sevan and its basin may serve as a classical example in this respect in the world limnology, there has been no other case when a lake level would be artificially lowered by 18 meters for 3-4 decades (1930-70 s), and by another 2 meters at the end of 20th century (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000) and the volume of water in the lake decreased from 58 billion m3 to 32 billion m3. it must be noted that the drop of the lake level, and the economic development in the basin brought about the change in the hydrological regime of the lake. The latter caused the disruption of the hydro chemical and hydrobiological regimes of the lake. The quality of the water deteriorated; water turbidity increased. The inner circulation of the water substances, as well as the circulation of the biological substances altered as well.

Numerous rivers, lakes and other water features have suffered significant alterations as a result of human economic activity. As a result, hydrometric, hydrological, biological, ecological conditions, as well as morphometric elements of these objects were violated. In this regard, Lake Sevan and its basin might be used as a well-known example. There has never been any instance in the history of limnology where a lake’s level was artificially lowered by 18 meters over 3 to 4 decades (1930–1970), and by another 2 meters at the end of the 20th century (1990–2000). Additionally, the lake’s water volume dropped from 58 billion m3 to 32 billion m3. The Sevan problem first surfaced in the late 19th and early 20th centuries and is still a problem today. However, it has many meanings/soundings at different times. Based on this, we usually divided the entire study period into several stages. It should be noted that the ecosystem has suffered irreparable losses as a result of the use of the Lake Sevan resources, inadequate water resource management, and both positive and negative effects of these factors. We disagree with the assertions of many experts that problems can only be prevented or solved by raising the lake level. Therefore, extensive actions must be taken in the Sevan basin management area, regardless of the lake’s level.

The study concerned the analysis of temporal and spatial variability of floods in the Republic of Armenia (RA). While there are number of reports on flood formation of rivers in RA, the literature lacks results on using nonparametric test results to analyze this disastrous phenomenon. For that purpose, the dynamics of changes in extreme maximum instantaneous runoff, as well as air temperature and precipitation database was evaluated and compared between 1960–2012 for 27 hydrometrical observational and 35 meteorological stations in RA. The Mann-Kendall test with consideration of the autocorrelation function was employed as a non-parametric testto identify any present trends. An increasing tendency of air temperature, decreasing tendency of the atmospheric precipitation and extreme maximum instantaneous river runoff were identified in the studied river-basins. As expected, the warming climate contributed to a gradual melting of accumulated snow in the river-basins in winter, resulting in changes in the extreme maximum instantaneous runoff of the rivers in spring, which significantly reduces the risk of the flood occurrence. Thus, it can be claimed that almost all the river basins of Armenia have a tendency to reduce the risk of floods due to global climate change.