Current hydroecological state of the Ural River in the lower reaches

Climate and hydrological changes in the Ural River basin, together with water management activities determine the current hydroecological state of the river in its lower course. In comparison with the conventional natural background, the salinity of water in high water period increased by 2.5 times, in low water period- by 5-8 %. Contamination of the lower course of the river is caused by the inflow of pollutants from the upstream sections and the confluence of the polluted tributaries. In the area with no tributaries, the water is characterized as “standard-clean”. The saprobity indices, which characterize the content of organic substances in water, are located within the boundaries of the b-mesosaprobic zone, which characterize low level of water contamination. The content of dissolved oxygen indicates insufficient aeration of the river water during most of the year. The lowest oxygen content is observed during winter period.