Altered Precipitation and Flow Patterns in the Dunajec River Basin

Abstract

This study analyzes changes in long-term patterns of precipitation and river flow, as well as changes in their variability over the most recent 60 years . The study area is situated in the mountain basin of the Dunajec River, encompassing streams draining the Tatra Mountains in southern Poland. The focus of the study was to evaluate how regional warming translates into precipitation changes in the studied mountain region, and how changes in climate affect sub-regional hydrology. Monthly time series of precipitation measured at several sites were compared for two 30-year periods (1986-2015 versus 1956-1985). The significance of the difference between the periods in question was evaluated by means of the Wilcoxon signed rank test with the Bonferroni correction. The identified shifts in precipitation for 6 months are statistically significant and largely consistent with the revealed changes in river flow patterns. Moreover, significant differences in precipitation variability were noted in the study area, resulting in a significant decrease in the repeatability of precipitation over the most recent 30 years . Changes in the variability of the river flow studied were less visible in this particular mountain region (while significant for two months); however, the overall repeatability of river flow decreased significantly at the same rate as for precipitation.

Long-term trends in river flow: a case study of the Soła River (Polish Carpathians)

“…4) for the downstream site only, which is accompanied by a decreasing trend in P (minimum values of P at Oświęcim). On the other hand, summer is the only season when all remaining trends in Q and P (Table 4 and 5, respectively) show a decreasing, yet statistically insignificant, tendency consistent with revealed, significant decreases in summer Q and P for the mentioned nearby catchments [27,43]. No trend in autumn Q was identified, while increasing trends in autumn precipitation were found (at Lipowa and Kocierz Moszczanicki).…”

“…An increasing trend in winter Q (at Żywiec) is consistent with a similar trend in winter P (mean, minimum, and maximum values of P at a nearby site, Lipowa). An increasing trend in spring Q can be associated with increased spring precipitation regionally, especially for March and May, as revealed for the neighbouring catchments of the Skawa, Raba, and Dunajec rivers [27,43]; moreover, it corresponds with an increase in spring P found at Kocierz Moszczanicki. However, such an increasing tendency in spring Q is absent for the downstream site (28 km downstream from the CR dam), and even a decreasing tendency is present (minimum values, Fig.…”

“…The impact of a changing climate, mainly atmospheric warming, on freshwater resources and the functioning of aquatic ecosystems has been extensively studied over the last few decades [20][21][22][23][24][25][26][27]. The warming trend in global mean surface air temperature of 0.12 °C per decade [28], accompanied by likely changes in precipitation [29], may worsen flow and thermal conditions in fluvial environments, with serious implications for both aquatic life and humans.…”

Sensitivity of mountain catchments to global warming: a case study of the San Basin, Poland

“…September to October, but a decrease from June to August and in December. Importantly, the directions of changes in P for 6 months (March, May, June, August, September and December) are consistent with previous results (Kędra, 2017a) obtained for the high-mountain basin of the Dunajec River; moreover, changes in P in March, May, August and September are also in line with the results for two Beskid catchments located in the Polish Western Carpathians (Kędra, 2017b). Regarding Q, the comparison of changes for the last 30 years and the previous period shows a significant increase in Q in January, consistent with the trend analysis, as well as other important changes, including a marked increase in Q in February, May and September, and lowering the flow in July, August and December; however, the resulting change in annual Q proved insignificant (Table 8).…”

Long-Term Variability of Runoff of Vistula River in 1951-2015.

“…Detection of river discharge changes trends in Polish conditions have been done mainly in rivers with small and medium basins, and relatively unchanged discharge regime (semi-natural and natural basins) (Kędra, 2017;Piniewski et al, 2018). Determination of discharge variability in basins of large rivers and detection of main causes of discharge changes is exceptionally hard due to the influence of not only meteorological conditions but also anthropogenic which take place on significantly large portion of the river basin.…”