Influence of climate change on river discharges over the Sava River watershed in Bosnia and Herzegovina

Abstract

The paper examines changes in air temperature, precipitation, and river discharges on seasonal and annual scale over the Sava River watershed in Bosnia & Herzegovina during the period 1961–2016. Based upon data gathered from 11 meteorological stations and 3 hydrological stations, hydroclimatic variables trends were established by utilizing the nonparametric Mann-Kendall test and the nonparametric Sen’s slope estimator. The results show significant positive seasonal and annual trends (expect for autumn, during which upward trends were insignificant) in air temperature, whereas both positive and negative insignificant seasonal and annual precipitation trends are shown where determined for the entire watershed. Most prominent upward trends in air temperature were found in summer and afterwards in winter and spring, indicating a pronounced warming tendency over the Sava River watershed. Trends in river discharge displayed a negative tendency in all seasons. Nevertheless, a majority of estimated trends of river discharges were weak and statistically insignificant. Throughout the year, river discharges showed significant positive correlation with precipitation, whilst connection with air temperature was mostly significant and negative. The study results suggest that climate is an important factor affecting river regimes, as well as that changes in river discharges are reflecting recent abrupt changes in climatic variables.

Changing Water Cycle under a Warming Climate: Tendencies in the Carpathian Basin

“…Clear pieces of evidence are based on analyses of hourly or daily temperatures, [26][27][28], extreme values [29,30] or the frequency of warm spells [29,31]. The representativity is supported by evaluation of temperature time-series in Bačka (Serbia) [32] and over the Sava River watershed (Bosnia and Herzegovina) [33], where each meteorological station also recorded very similar warming trends.…”

Прoмjeнe Вриjeднoсти Климaтских Eлeмeнaтa И Њихoв Утицaj Нa Вoдни Рeжим Горњег Тока Тaрe

“…Aнaлизe сa глoбaлнoг (Do et al, 2017;Kleinen & Petschel-Held, 2007;Milly et al, 2005), рeгиoнaлнoг (Blöschl et al, 2019;Bouwer et al, 2008;Dankers & Feyen, 2008;Kundzewicz et al, 2013;Lehner et al, 2006) дo националног и лoкaлнoг нивoa (Gnjato et al, 2019;Kovačević-Majkić & Urošev, 2014;Oblak et al, 2021;Pandžić et al, 2009) пoкaзуjу дa су сe у нeким рeгиoнимa и oблaстимa дeсилe знaчajнe флуктуaциje риjeчнoг рeжимa (било у правцу повећане учесталости поплава или смањења протицаја), a тимe и нa ширeм пoдручjу истрaживaнoг прoстoрa. Анализе промјена протицаја вршене су на бројним ријекама у региону -Дунав (Dolinaj et al, 2019;Rimbu et al, 2002;Čanjevac, 2012), Сава (Gnjato et al, 2021;Leščešen et al, 2021;Oblak et al, 2021;Orešić et al, 2017;Pandžić & Trninić, 1998;Pandžić et al, 2009;Stojković et al, 2014), Mура (Oblak et al, 2021;Frantar & Hrvatin, 2005;Čanjevac & Orešić, 2015), Драва (Bonacci & Oskoruš, 2010;Oblak et al, 2021), Соча (Ulaga et al, 2008), Врбас (Gnjato et al, 2019), Сана (Gnjato, 2018), Требишњица (Gnjato et al, 2023), Западна Морава (Langović et al, 2017), Toплица (Martić Bursać et al, 2016, Тимок и Јужна Морава (Kovačević-Мajkić & Urošev, 2014), Нишава (Đokić et al, 2022), као и у Црној Гори -Moрача…”

“…Analyzes from the global (Do et al, 2017;Kleinen & Petschel-Held, 2007;Milly et al, 2005), regional (Blöschl et al, 2019;Bouwer et al, 2008;Dankers & Feyen, 2008;Kundzewicz et al, 2013;Lehner et al, 2006) to national and local levels (Gnjato et al, 2019;Kovačević-Majkić & Urošev, 2014;Oblak et al, 2021;Pandžić et al, 2009) show that in certain regions and areas there have been significant fluctuations in the river regime; and therefore in the wider area of the researched area. Analyzes of flow changes were carried out on numerous rivers in the region -Danube (Dolinaj et al, 2019;Rimbu et al, 2002;Čanjevac, 2012), Sava (Gnjato et al, 2021;Leščešen et al, 2021;Oblak et al, 2021;Orešić et al, 2017;Pandžić & Trninić, 1998;Pandžić et al, 2009;Stojković et al, 2014), Mura (Oblak et al, 2021;Frantar & Hrvatin, 2005;Čanjevac & Orešić, 2015), Drava (Bonacci & Oskoruš, 2010;Oblak et al, 2021), Soča (Ulaga et al, 2008), Vrbas (Gnjato et al, 2019), Sana (Gnjato, 2018), Trebišnjica (Gnjato et al, 2023), Zapadna Morava (Langović et al, 2017), Toplica (Martić Bursać et al, 2016, Timok and Južna Morava (Kovačević-Мajkić & Urošev, 2014), Nišava (Đokić et al, 2022), as well as in Montenegro -Morača …”

Spatio-temporal patterns of flooded areas in the lower part of the Sana river basin (Bosnia and Herzegovina)

“…Trends in river discharges in Bosnia and Herzegovina are similar to the trends in the southeastern part of Europe. Mean annual discharges for Bosna, Vrbas, Vrbanja and Sana rivers displayed downward trends (Gnjato, 2018;Gnjato et al, 2019;Gnjato et al, 2021;Hadžić & Drešković, 2014). The most prominent decrease in river discharges was determined during the summer season at Sana and Vrbanja rivers (Gnjato et al, 2021).…”

“…Mean annual discharges for Bosna, Vrbas, Vrbanja and Sana rivers displayed downward trends (Gnjato, 2018;Gnjato et al, 2019;Gnjato et al, 2021;Hadžić & Drešković, 2014). The most prominent decrease in river discharges was determined during the summer season at Sana and Vrbanja rivers (Gnjato et al, 2021). Regarding the increase in extreme precipitation in the region, it is expected that flooding in smaller basins could increase (Blöschl et al, 2019).…”