Hydroecological limitations of the use of water resources of transboundary rivers of the steppe zone (through the example of the Ural and Tobol Rivers, Russia)

To identify the main types of hydroecological restriction on the use of water resources and their spatial patterns in the Ural and Tobol river basins within the steppe zone.A comprehensive assessment of the water‐environmental situation in the regions of the studied basins studied was carried out on the basis of the calculation of water‐environmental stress – the ratio of water intake and free flow (average long‐term flow minus ecological). To assess the environmental restrictions on water use, data from the State reports, “On the State and Protection of the Environment" were used. Exposure to the risk of flooding of settlements was analysed according to information from the registers of settlements at risk of flooding (flooding). Analysis of the dynamics of channel processes was carried out using Landsat satellite images. For the rivers of the Tobol River basin, an approach based on taking into account the nature of channel transformations in the sectors of the state border of the Russian Federation and the Republic of Kazakhstan was used.As a result of the research, the main types of hydroecological restriction in the transboundary basins of the Ural and Tobol were identified. In particular, the key factor limiting water use is the availability of a guaranteed volume and adequate quality of water resources. Hydrological restrictions associated with the negative impact of water include the risks of flooding of settlements during the passage of spring or summer floods, as well as intensive riverbed transformations (in the Ural River basin).The Ural and Tobol river basins (within the steppe zone) are characterised by the development of a rather complex hydroecological situation in some areas. Taking into account the long cycle of low water content in these rivers, the general hydroecological situation has aggravated in recent decades, the primary problem being that of guaranteed provision of water resources of standard quality. As a result, an urgent task is to develop an algorithm for a comprehensive assessment of hydroecological restrictions on water use and their consequences for the population and economy of the regions of the steppe zone.