ИСТИНА

The following main scientific, methodological and practical results were obtained during the dissertation research: • The spatial-temporal change of river runoff characteristics, restorable water resources and typical discharges of river water for the rivers in Armenia reflects the global changes of humidity circulation processes on the Earth and is closely related to regional factors which control the change in air temperature and the aggregate precipitation. • The changes in the volume of restorable water resources and runoff regime of rives in the Armenia are mainly caused by climatic factors. In some small river basins runoff is considerably influenced by the relief and hydro-geological conditions, which violate the common spatial-temporal regularities of changes in river runoff. • The rivers of Armenia have been subject to significant technogenic pressure, which has brought about changes in the natural runoff of rivers, water regime and water quality. The water resources of the Hrazdan, Akhourian, Kasakh, Azat, Vedi, Vorotan rivers have undergone the maximal quantitative change river runoff, while the Hrazdan, Debed, Sevjur and Voghji rivers have been mostly influenced when measured by an index of water contamination. The rivers are classified as “highly contaminated”, while in some smaller tributaries of these rivers one observes “extremely high contamination”. • In the 20th century, the restorable water resources of Armenia have undergone considerable changes. In major part of the country's territory, in the mountainous and lowland areas of river basins, the restorable water resources increased in the 1930-2000s. On 14.8% of the observed territory they have decreased, and on 22.2% of the territory they have remained unchanged. • The total volume of the restorable water resources of the main rivers in Armenia has not undergone intentional changes. In 1950-1991s it grew by 4-5%, in 1961-1991s it was close to the norm, while in 1950-2000s its slight decrease (by 1%) was observed, which corresponds to the general regularity of the global change in the runoff in the inland regions of the Earth. Nearly a similar situation was observed in 1950-2010s; however, in this case no tendency of runoff decrease has been noticed. • The transformation of the intra-annual discharge of river runoff in Armenia is expressed in the reduction of the summer-autumn low-water and the spring maximal discharge, as well as in the growth of winter low-water runoff. • The changes of perennial mean annual, maximal and minimal 30-day river runoff in Armenia are controlled by the change of the aggregate precipitation and air temperature. In some separate small river basins, this regularity may be violated as a result of the influence of relief and hydro-geological conditions. • River runoff fluctuations have a quasi-periodical nature. The periods of increased and decreased runoff correspond to the rhythm of fluctuations of the aggregate precipitation. The mean duration of fluctuation periods for bankful rivers is 7 to 11 years. • For three scenarios of global warming developed by the author, river runoff will most likely decrease. On the average, in the period of 2050-2075, it will decrease by 11,67%, compared with the average of years 1950-2000s. These estimates correspond to the IPCC forecasts for the inland regions of the Earth • The maximal value (-18,9%) of the river runoff decrease is expected in case of the third scenario developed by the author (T+2,00C; 0,9P). By PRECIS method, it will decrease by 16,8%, while in 2071-2100 by 24,9%. Under the anticipated global hydro-climatic changes, water economy of the country becomes particularly vulnerable. The reduction of the volume of restorable water resources and growth of air temperature will lead to increase in water amount required for irrigation and water supply, and it will affect the sustainable development of society in the country. To prevent it, we suggest envisaging and implementing a complex of special measures, directed at minimisation of the social, economic and ecological damage. The gradual implementation of these measures will ensure the sustainable development in the country, considering the global change of climate as well.