water Article A Comparative Analysis of Exceptional Flood Events in the Context of Heavy Rains in the Summer of 2010: Siret Basin (NE Romania) Case Study Gheorghe Romanescu 1 ID , Alin Mihu-Pintilie 2,* ID , Cristian Constantin Stoleriu 1, Donatella Carboni 3, Larisa Elena Paveluc 1 and Catalin Ioan Cimpianu 1 1 Department of Geography, Faculty of Geography and Geology, Alexandru Ioan Cuza University of Iasi (UAIC), RO-700505 Iasi, Romania; [email protected] (G.R.); [email protected] (C.C.S.); [email protected] (L.E.P.); [email protected] (C.I.C.) 2 Interdisciplinary Research Department, Field Science, Alexandru Ioan Cuza University of Iasi (UAIC), RO-700107 Iasi, Romania 3 Dipartimento di Scienze Umanistiche e Sociali, Università degli Studi di Sassari, Via Roma 151, 07100 Sassari, Italy; [email protected] * Correspondence: [email protected]; Tel.: +40-741-912-245 Received: 8 January 2018; Accepted: 12 February 2018; Published: 17 February 2018 Abstract: The Siret River crosses northeastern (NE) Romania from the north to the south, and it discharges into the Danube, near the city of Galati. Between 17 June and 10 July 2010, significant amounts of precipitations in the mountainous basin of Siret were recorded. The floods comprised two periods with four bimodal cycles, and they were counted as among the strongest on the Romanian territory. The exceptional floods occurred in the rivers of Siret, Suceava, Moldova, Bistrita, Trotus, and so on. The most important compound flood wave was determined by the precipitations, which fell between 29 June and 1 July 2010, when significant amounts of rain were recorded, sometimes exceeding 80 mm/day. The high discharges on the Bistrita River—downstream from the Bicaz Reservoir—were controlled by complex hydro-technical works. The maximum discharge for summer floods in the year 2010 was recorded at the Dragesti hydrometric station: 2884 m3/s (historic discharge) compared with the preceding historic discharge (2850 m3/s) of the year 2008. The effects of floods were strongest in the counties of Suceava, Neamt, and Bacau. The floods on the main course of the Siret River were analyzed in correlation with the tributaries within the mountainous sector. Keywords: continental climate; exceptional floods; historic discharge; hydro-technical works; material damage; Siret catchment basin; NE Romania 1. Introduction The year 2010 was one of the most dangerous from the perspective of catastrophic floods in Central-Eastern Europe. The months of May–June recorded some of the strongest floods in both central and eastern Europe: Poland, Austria, Czech Republic, Germany, Hungary, Slovakia, Serbia, Ukraine, Slovenia, Bosnia, Herzegovina, Montenegro, Croatia, Romania, and so on [1–4]. On the Romanian territory, exceptional floods occurred in the rivers of Siret, Prut, Tisa, Somes, Olt, and Tarnave [3–7]. In Europe, the number of human losses was significant [8]: Poland—25 victims [44], Romania—six victims [3], Slovakia—three victims, Serbia—two victims, Hungary—two victims, and the Czech Republic—two victims (Figure1). Water 2018, 10, 216; doi:10.3390/w10020216 www.mdpi.com/journal/water Water 2018, 10, 216 2 of 17 Water 2018, 10, x 2 of 17 FigureFigure 1. 1.Major Major floodsfloods events within within the the Danube Danube basin basin and and the surrounding the surrounding areas that areas occurred that occurred from May from Mayto June to June 2010. 2010. TheThe international international literature has has analyzed analyzed in indetail detail the themost most important important floods floods that occurred that occurred over time over timearound around the world the world [9–16]. [9 From–16]. this From perspective, this perspective, the historic the floods, historic or floods,those that or produced those that important produced importantmaterial damage material or damage human losses or human, are worth losses, underscoring are worth underscoring [17–30]. The recent [17–30 catastrophic]. The recent floods catastrophic on the floodsRomanian on the territory Romanian—mostly territory—mostly in the east (Moldova in the east region) (Moldova [3–7]— region)motivated [3– scientists7]—motivated to pen scientistsscientific to works that also dealt with the issue of heavy rains [31–33]. pen scientific works that also dealt with the issue of heavy rains [31–33]. The largest catchment basin in the Romanian territory, the Siret catchment basin, comprises the The largest catchment basin in the Romanian territory, the Siret catchment basin, comprises the Siret River [2,4], and the mountains and plateaus in the catchment area have showed different patterns of Siret River [2,4], and the mountains and plateaus in the catchment area have showed different patterns precipitation [31]. At the same time, the Siret catchment basin comprises the highest number of dams in of precipitation [31]. At the same time, the Siret catchment basin comprises the highest number of Romania [33]. dams inThe Romania Siret River [33 is]. the most important hydrographic artery in Romania (after Danube): 220 m3/s, 559 3 kmThe in length, Siret River and is42,890 the most km2 importanton the Romanian hydrographic territory artery (44,871 in Romaniakm2 overall). (after It Danube):springs from 220 the m /s, 2 2 559Ukrainian km in length, Carpathians, and 42,890 where km its onupper the Romanianstream unfolds, territory and (44,871then, its kmmiddleoverall). and lower It springs streams from cut the Ukrainianacross the Carpathians, east of Romania. where It discharges its upper into stream the Danube unfolds, south and from then, the its city middle of Galati. and lowerIt comprises streams the cut acrossrichest the hydrographica east of Romania.l network: It discharges 1,013 rivers, into measuring the Danube 15,157 south km from overall the, citymeaning of Galati. 19.2% It of comprises Romania. the richestIts forestry hydrographical fund comprises network: 15,882 1013 km rivers,2, which measuring represents 15,15737% ofkm the overall,catchment meaning surface 19.2% and 25% of Romania.of the Itsentire forestry forestry fund fund comprises in Romania 15,882 [31 km–332], (Figure which 2a). represents 37% of the catchment surface and 25% of the entire forestryThe Siret fund basin in has Romania the following [31–33 coordinates:] (Figure2a). northern limit—47°58′ N; southern limit—45°28′ N; westernThe Siret limit basin—24°49 has′ E; the eastern following limit coordinates:—28°2′ E. The northern level difference limit—47 ◦58between0 N; southern the sources limit—45 and ◦the280 N; westerndischarge limit—24 mouth ◦is49 12360 E; m. eastern The catchment limit—28 is◦ typically20 E. The asymmetrical, level difference because between it was cr theeated sources on the andright the discharge(Carpathian mouth Mts. is sector), 1236 m. on The the catchmentbasis of mountainous is typically tributaries asymmetrical, [2]. The because hydrographical it was created network on the rightincludes (Carpathian the Siret Mts. River sector), and its onmain the tributaries, basis of mountainous which spring tributariesfrom the mountainous [2]. The hydrographical area: Siretul Mic network (on includesthe Ukrainian the Siret territory), River and Suceav its maina, Moldova, tributaries, Bistrita, which Trotus, spring Putna, from Ramnicu the mountainous Sarat, and Buzau. area: The Siretul only Mic (onimportant the Ukrainian tributary territory), on the left Suceava, is Barlad (Figure Moldova, 2b). Bistrita, Trotus, Putna, Ramnicu Sarat, and Buzau. The onlyThis important study emphasizes tributary onthe therole left played is Barlad by locally (Figure heavy2b). rains at the onset of floods, and the importance of large reservoirs in the mitigation of flood waves (Figure 2c). Another purpose of the article This study emphasizes the role played by locally heavy rains at the onset of floods, and the is to evaluate the relationship between mountainous rivers (tributaries of Siret) and water supply during importance of large reservoirs in the mitigation of flood waves (Figure2c). Another purpose of the floods. Flood waves are controlled by the reservoirs, which have taken over a part of the excessive article is to evaluate the relationship between mountainous rivers (tributaries of Siret) and water discharge in the context of climate change in recent decades. supply during floods. Flood waves are controlled by the reservoirs, which have taken over a part of the excessive discharge in the context of climate change in recent decades. Water 2018, 10, 216 3 of 17 Water 2018, 10, x 3 of 17 FigureFigure 2. 2.( a(a)) Geographic Geographic location of of the the Siret Siret catchment catchment on on the the Romanian Romanian territory; territory; spatial spatial distribution distribution of ofthe the (b ()b stud) studiedied rivers rivers and and(c) hydrometric (c) hydrometric stations, stations, with the with role of the mitigating role of mitigatingfloods in the floods Siret catchment in the Siret catchmentarea. area. TheThe greatest greatest damage damage waswas producedproduced in Suceava County County by by the the Suceava Suceava River River and and its itstributaries tributaries in in thethe Neamt Neamt County County by by Moldova Moldova and and Siret, Siret, and and in the in Bacau the Bacau County County by Trotus by Trotusand Siret and (Figure Siret 3a). (Figure In the3 a). Inloc thealities localities of Saucesti of Saucesti and Letea and Veche Letea (Bacau Veche County), (Bacau County),floods damaged floods 1110 damaged houses, 1110 4000 houses, ha of arable 4000 ha ofland, arable and land, the entire andthe infrastructure. entire infrastructure. Furthermore, Furthermore, 2137 persons were 2137 affe personscted by were the floods affected (Figure by the 3b– floodsd). The effects of the floods were significant in the counties of Suceava, Neamt, and Bacau (Figure 3e,f). For (Figure3b–d). The effects of the floods were significant in the counties of Suceava, Neamt, and Bacau the purpose of population safety, employees with the Inspectorate for Emergency Situations and the (Figure3e,f). For the purpose of population safety, employees with the Inspectorate for Emergency Romanian Army organized an intervention (Figure 3g).