Changes in the annual runoff module of small rivers in the Russian part of the Ural River basin

Relevance. Currently, the main studies of the runoff modulus and the dynamics of its changes are conducted mainly on medium and large rivers of the Russian part of the Ural River basin, while the study of the runoff modulus of small rivers in this basin is extremely poor. Given the increasing deterioration of the ecological state of rivers, which primarily affects the annual water runoff modulus on small rivers, the study of the processes of runoff modulus formation, its variability and intra-annual changes are becoming the most important task of hydrology. Methods. The study is based on a comprehensive analysis of the annual water runoff modulus of small rivers in the Russian part of the Ural River basin. A database of cartographic and hydrological information has been formed. The paper presents a mapping of changes in the annual runoff modulus of small rivers, which has not previously been applied to the quantitative characteristics of small river runoff. Results. Changes in the runoff modulus of small rivers in the Ural River basin are considered, with almost complete lack of study of changes in the runoff of small rivers. An analysis of the characteristic before and after the onset of global hydrological changes is made. Spatio-temporal trends in changes in the runoff modulus of small rivers in the Ural Basin are revealed. The boundary of the anomaly of small rivers by the basin area was identified – by the size of the river basin of 500 km2.