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

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.

Warming Vistula River – the effects of climate and local conditions on water temperature in one of the largest rivers in Europe

“…We assume that it should be associated with the importance of the effect of regional factors. According to Wrzesiński and Sobkowiak (2020), transformation of the hydrological regime of the Vistula River, observed in multi-annual and annual models, occurred on the entire length of the river, although the most frequent changes were determined in its upper course, based on the characteristics of discharges of its tributaries. In the transit section of Vistula, until Puławy, the river regime is shaped by its mountain tributaries carrying water from the Carpathians, and Vistula is characterised by a high variability of annual runoff here.…”

“…Compared to other large European rivers, the impact of hydrotechnical constructions on the regime of the Vistula River is relatively limited (Wrzesiński and Sobkowiak, 2020). The two largest dams are: Goczałkowice (reservoir volume 168 million m 3 ) and Włocławek (reservoir volume 408 million m 3 ).…”

Comparison of Three-Parameter Distributions in Controlled Catchments for a Stationary and Non-Stationary Data Series

“…The characteristics and the classification of the hydrological regime is presented in Appendix A (Table A1). The hydrological regime depends on the number of floods per year and the source of supply (Parde classification) and the variability of flows per year (Dynowska classification) [47][48][49][50][51][52]. The supplement in Appendix A (Figure A1) shows the variability of long-term monthly flow rates.…”

Relationships of Hydrological Seasons in Rivers and Groundwaters in Selected Catchments in Poland

“…For clustering, the most frequently used Ward's method was chosen [21,22]. This is a wellknown and described procedure, used in hydrological research, including assessment of changes in river regimes [23][24][25][26][27][28]. It should be highlighted that the procedure is very sensitive to differences in the variance of agglomerated data, and the time series with the highest variance have the greatest impact on the identified clusters.…”