Analysis of the Course and Frequency of High Water Stages in Selected Catchments of the Upper Vistula Basin in the South of Poland

Abstract

Abstract:The paper presents an analysis of the course and frequency of high water stages in selected catchments of the upper Vistula basin in the south of Poland. The following rivers were investigated: the Dunajec-Nowy Targ-Kowaniec cross-section, the Rudawa-Balice cross-section, the Kamienica-Nowy Sącz cross-section, the Wisłok-Tryńcza cross-section and the San-Przemyśl cross-section. Daily flows from the years 1983-2014 were used to determine maximum annual flows and maximum flows per summer and winter half-year. Selected floods were analyzed with reference to the following metrics: POTX (mean size of the flow determined based on high water stages exceeding the assumed threshold value), POT3F (number of high water stages exceeding the threshold value for each hydrological year), WPOT3F (number of high water stages exceeding the threshold value for the winter half-year and), LOPT3F (number of high water stages exceeding the threshold value for the summer half-year). The determined metrics were analyzed for trend (Mann-Kendall test), homogeneity (Kruskal-Wallis test), and heteroscedasticity (Levene test). Additionally, periodograms were used to determine periodicity of time series for maximum annual flows. The resulting computations indicated upward trends in the analyzed flood metrics but they were not significant in any case. Therefore, in the years 1983-2014 no factors were observed that would significantly affect the size and frequency of high water runoff from the investigated catchments.

A New Empirical Approach to Calculating Flood Frequency in Ungauged Catchments: A Case Study of the Upper Vistula Basin, Poland

“…Therefore, in the analysed multi-year period, no factor has appeared that would significantly affect the course of processes shaping flood flows from these catchments. Similar research results related to the analysis of changes in the flood flows from the catchments of the upper Vistula river basin are presented in the papers [35,36], where in the majority of the studied cases there were also no statistically significant trends found in the observation series of flood flows in the upper Vistula basin. Bearing in mind that the observation series adopted for further analysis should meet the requirements of a simple random sample, the following catchments were excluded from further research: Bystra-Kamesznica, Skawica-Zawoja, Stryszawka-Sucha, Raba-Rabka, and Grajcarek-Szczawnica.…”

Trends, Variability, and Seasonality of Maximum Annual Daily Precipitation in the Upper Vistula Basin, Poland

“…Insignificant trends observed for the majority of weather stations in our study reflected the course of high water in the catchments of the Upper Vistula Basin. Research conducted by Kundzewicz et al [46], Wałęga et al [47], and Młyński et al [48] showed a stable runoff of high water in the catchments of the Upper Vistula Basin in recent decades. Flood size in this region depends on multiple factors such as geology, soils, geomorphological evolution, landscape structure, or land use.…”

Spatio-temporal changes in atmospheric precipitation over south-western Poland between the periods 1891–1930 and 1981–2010

“…Increased winter precipitation in the mountains raises the flooding risk, even if the coincidental rise in air temperature increases the frequency of rainfall instead of snowfall. The increased frequency of high water stages has been reported by Walega et al (2016). Climate change projection also suggests that changes in cyclone track may increase the extreme precipitation events (Nissen et al 2013).…”

“…The changes of thermal regime means, among others, shorter winters and changes of precipitations forms with greater proportion of mixed and liquid precipitation, especially in winter (Twardosz et al 2012;Taskinen and Söderholm 2016). For solid precipitation, gauge undercatch at the same wind speed is higher than for rain (Wagner 2009), so the observed increase in November-March precipitation sums in the Sudetes may be partly caused by lesser measurement losses in changing thermal conditions.…”