ИСТИНА

The Ural River is the third in the list of European rivers by its length. Its length is 2428 km and basin area is 237 000 km2. The basin occupies the territory of Russia and Kazakhstan. The Ural River is considered a transboundary water body, which didn’t escape problems due to sharing water resources. Main problems are a decrease in water levels and maximum discharges during spring flood, a decrease of annual water runoff and polluting river water. They negatively affect the living conditions of fish, productivity of floodplains and possibility of using river water for settlements. The authors found that the current long-term low-water period began in 2006-2008 and continues to this day, despite an increase in precipitation in the winter and spring seasons in the 21st century. Runoff and maximum discharges of spring flood in the Lower Ural has decreased by 27 and 55-43%. Now the flood season begins and ends 9 and 5 days earlier. Runoff of the summer-autumn and winter low-water seasons has increased by 56-42 and 70-61%, the winter duration - by 18 days. Intra-annual fluctuations of water discharges and levels have decreased significantly. Large inundations have not been since the mid-1990s. There are several reasons. These are obvious regional climatic changes: an increase of air temperature, frequency and duration of winter thaws, and a change in precipitation regime and snow cover during November-March. It is also a consequence of the regulation of Ural River by the Iriklinskiy reservoir and 3130 smaller reservoirs and numerous ponds; irrevocable intake of river waters (~2.38 km3/yr in 1985-1990 and ~1.1 in 1999-2007); wastewater discharges; man-made landscape changes. Problems in the transboundary water use are compounded, although it is regulated by several international documents. The authors offer their assessment of the current situation, the contribution of each of the factor and ways to solve these problems. The investigations were carried due to theme 121051400038-1 and an agreement with the Atyrau region.