The paper analyses the impact of recent climate change on river discharges
in Bosnia and Herzegovina. Data on mean monthly precipitation, temperature and
discharges from the Banjaluka meteorological station and from the Delibašino Selo
(Banjaluka) hydrological station during the 1961–2016 periods were used for calcu-
lations of annual and seasonal trends in the Lower Vrbas River basin (which was cho-
sen for the case study). The nonparametric Mann-Kendall test and the Sen’s method
were used to assess the trend magnitude and its statistical significance, whereas the
Pearson correlation index was chosen to detect the connections between climatic
and river discharge data series. Given the results, a significant warming tendency
was present throughout the year. Annual temperature increased 0.46 °C per decade.
Unlike temperature, trends in annual and seasonal precipitation were mixed in sign,
but were all insignificant. During the observed period, river discharges displayed a
significant negative correlation with temperatures throughout the year (insignificant
only in winter), whereas links with precipitation were significant and positive. As
a result of the determined climate variability, annual river discharges showed a sig-
nificant downward trend in the range of −8.74 m3 /s per decade. Negative discharge
trends were detected in all seasons, but were most prominent in winter and spring.
The observed changes in river discharges were strongly related to the large-scale
atmospheric circulation patterns over the Northern Hemisphere: the Artic Oscilla-
tion pattern, the East-Atlantic pattern, the North Atlantic Oscillation and the East
Atlantic-West Russia pattern. A significant warming of the climate system, combined with the downward discharge trends throughout the year and precipitation decrease in summer, will lead to decreased water availability over the Lower Vrbas River
basin in the future. Given the stated, adaptation towards the observed and projected
climate change will be necessary in all key sectors in Bosnia and Herzegovina such
as agriculture, energetics (hydropower) and tourism. The adaptation and mitigation
options aimed to increase their resilience were considered.
