Climatic changes and water management in the Ural River basin and their impact on the river water regime

Abstract

The Ural River basin is a transboundary object, which is characterized by a very uneven distribution of water resources, an extensive arid areas and water-intensive socio-economic complex. There are about 3,130 reservoirs and ponds, which are evaporating 0.9 km3/yr. and carry out intra-annual regulation. Water intake peaked in the 1980s. Now the anthropogenic decrease in runoff is < 1.6 km3/yr. Climate warming has begun in 1977-1980 and has intensified since the mid-1990s, as well has the occurrence of thaws in winter. In the first half of the current period, annual, summer-autumn, and winter precipitation was higher than the average long-term values. In the second half, spring and winter precipitation increased, while total precipitation decreased due to decrease in summer-autumn precipitation. As a result, the modern water regime of rivers has clearly changed and not in all cases positively. This initiated an inter-State discussion on the efficient use of water resources. Therefore, the goal and objectives of the research were not only to assess the characteristics of the runoff, trends of their changes, but also to determine the role of climatic and anthropogenic factors and the patterns of their long-term behavior. An analysis of data at 56 gauges, 10 meteorological stations, and on water use shows that after 1977 the runoff exceeded by an average of 10-20%. 1985-1995 and 2000-2007 were high-water sub-periods. Since 2006/2008, the prolonged water shortage has been registered. The decrease in the precipitation and the increase in evaporation are the main reasons for its formation. The regulation of the Ural runoff and warming have led to an earlier commencement and ending of floods in the lower reaches, a decrease in its volume and maximum water discharges, and the inundation risk reduction. Low-water runoff has increased significantly. This is illustrated by the new data.