Transformation of the Flow Regime of a Large Allochthonous River in Central Europe—An Example of the Vistula River in Poland

Dariusz Wrzesiński,Leszek Sobkowiak

doi:10.3390/w12020507

Abstract

Identification of river flow regime and its possible changes caused by natural factors or human activity is one of major issues in modern hydrology. In such studies different approaches and different indicators can be used. The aim of this study is to determine changes in flow regime of the largest river in Poland—the Vistula, using new, more objectified coefficients and indices, based on data recorded in 22 gauges on the Vistula mainstream and 38 gauges on its tributaries in the multi-year period 1971–2010. The paper consists of three main parts: in the first part, in order to recognize changes in the flow regime characteristics along the Vistula, data from gauges located on the river mainstream were analyzed with the help of the theory of entropy. In the second part gauging stations on the Vistula mainstream and its tributaries were grouped; values of the newly introduced pentadic Pardé’s coefficient of flow (discharge) (PPC) were taken as the grouping criterion. In the third part of the study a novel method of determining river regime characteristics was applied: through the recognition of the temporal structure of hydrological phenomena and their changes in the annual cycle sequences of hydrological periods (characteristic phases of the hydrological cycle) on the Vistula River mainstream and its tributaries were identified and their occurrence in the yearly cycle was discussed. Based on the detected changes of the 73-pentad Pardé’s coefficients of flow four main types of rivers were distinguished. Transformation of the flow regime was reflected in the identified different sequences of hydrological periods in the average annual cycle. It was found that while transformation of the Vistula River regime occurred along its whole course, the most frequent changes were detected in its upper, mountainous reaches, under the influence of the flow characteristics of its tributaries. This allowed the Vistula to be considered the allochthonous river. These findings are interesting not only from a theoretical point of view, but they also can be valuable to stakeholders in the field of the Vistula River basin water management and hydrological forecasting, including flood protection, which has recently become a matter of growing concern due to the observed effects of climate change and human impact.

Highlights

The hydrological regime defines the state and responses of a river system with relation to the climatic system and the catchment’s physical-geographic characteristics [1]
This allowed the Vistula to be considered the allochthonous river. These findings are interesting from a theoretical point of view, but they can be valuable to stakeholders in the field of the Vistula River basin water management and hydrological forecasting, including flood protection, which has recently become a matter of growing concern due to the observed effects of climate change and human impact
Characteristics the Vistula of the Vistula River regime were distinguished along its course, from the source to the mouth (Figure 3): On the basis of the calculated coefficients and indices (Cv, CS, Hgr, Emax, Emin) the following types of the Vistula River regime were distinguished along its course, from the source to the mouth (Figure 3):

Summary

Introduction

The hydrological regime defines the state and responses of a river system with relation to the climatic system and the catchment’s physical-geographic characteristics [1]. Different flow regime patterns can be treated as some “preferred states” of the runoff system, which are more or less stable. In order to identify a change in any pattern (whatever the reason), it is necessary first of all to adequately. Water 2020, 12, 507 describe its initial state [2]. Multi-year variations in river discharge may result from environmental changes at a local scale (e.g., caused by human activity) or at regional and global scales (caused by climate changes). Hydrological data, including river discharge, may, serve as an indicator of climate changes [3]. Long-term fluctuations of hydrological and meteorological quantities have been the object of attention of hydrologists and climatologists since the beginning of the 20th century [4]

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Conclusion