Учет и оценка нестационарности при управлении водными ресурсами речного бассейна

Abstract

This paper considers the rationale for taking into account and assessing the non-stationarity of the development of hydrological processes in the Volga River basin when determining the parameters of the functioning of the Volga water management system. The main purpose of the study is to identify non-stationarity in the formation of river runoff and develop methods for its assessment. The problem of constructing a dynamic-stochastic model is solved, which takes into account the non-stationarity of the formation of river runoff in different periods of time. A generalization of the dynamic-stochastic approach for the analysis and evaluation of long-term fluctuations in the inflow of river waters of the Volga River near the city of Volgograd is made. The stochastic relationship between the runoff of adjacent years is expressed by the transition function that controls the Markov process. Stationarity (non-stationarity) of long-term fluctuations in river runoff was assessed using the Fisher criterion (homogeneity of sample variances), Student’s criterion (homogeneity of sample means), Kolmogorov-Smirnov criterion (homogeneity of samples) and pair correlation (presence of a trend). The description of the nature of the flow of hydrological processes is represented by a model determined by the dynamic-stochastic approach when considering the non-stationary process of the annual flow of the Volga River. Based on the application of the concept of quasi-stationarity, the functions of the availability of the annual flow of the Volga River are obtained, which are used for a probabilistic assessment of the inflow of river waters in the Volga basin. The analysis of long-term fluctuations of the annual runoff of the Volga River made it possible to reveal that the variability of the river runoff of the studied basin has two components – deterministic and random. The deterministic component manifests itself in the change in time of the average value of the flow of the Volga River, and the random component is observed in the irregular annual deviations of the flow from its average value (norm). This approach is used in the probabilistic assessment of the inflow of river waters in the Volga river basin.