Features of the Formation and Variability of Hydrological and Ecological Characteristics of Small Rivers in the Ural River Basin under the Joint Effect of Natural and Anthropogenic Factors.

In recent decades, the water management and environmental situation in the Ural River basin was rather tense. This is true for its parts both in the Russian Federation, where the major portion of water resources is formed, and in Kazakhstan. The quantitative and qualitative depletion of water resources in the following years and the abrupt deterioration of the environmental conditions in many parts of the river make it necessary to carry out a large-scale study of the problems at a geosystem level. The article presents the results of studying small rivers in the part of the Ural River basin within the Russian Federation territory, where river runoff and environmental conditions vary under the effect of a combination of natural and anthropogenic factors. The methodological base of the study is the geosystem approach and the basin principle, which enable a comprehensive study of the effect of a combination of natural and anthropogenic factors on the formation of variations of quantitative and qualitative characteristics of watercourses and the ecological conditions in them. The methods of study include generalization and analysis of the data of earlier studies, field studies and observations, sampling water and bottom sediments, zoning of the area under study by the types and levels of anthropogenic load, determination of the character of pollution of watercourses and changes in the ecological conditions in them, depending on the effect of specific types of economic activity. The study revealed specific features of the effect of human economic activity on small rivers and the natural complexes in their drainage areas. The characteristics of the space and time variations in the factors that cause changes in the slope and river runoff are determined. The features of the effect of anthropogenic factors on water quality in water objects and the ecological conditions in them are studied; proposals for ecological rehabilitation, preservation, and recovery of small rivers—tributaries of different orders of the transboundary Ural River—are substantiated. [ABSTRACT FROM AUTHOR]