SPATIUM UDC 556.166(282.243.744) No. 34, December 2015, pp. 64-69 Review paper DOI: 10.2298/SPAT1534064P

SPATIOTEMPORAL REVIEW OF THE TORRENTIAL FLOOD PHENOMENON IN THE MORAVA RIVER BASIN

Ana M. Petrović1 Ratko Ristić, Faculty of Forestry of the University, Belgrade, , Geographical Institute “Jovan Cvijić” of the Serbian Academy of Sciences and Arts, Belgrade, Serbia

Phenomenon of torrential floods as the most destructive and the most frequent natural hazards in Serbia with serious socioeconomic, cultural and environmental consequences deserve special attention. In this paper, data collection strategy and data analysis with the aim of spatiotemporal characterization of the torrential flood phenomenon in the largest national, Morava river basin, are presented. A dataset (derived from the Inventory of torrential floods in Serbia) of 479 registered torrential flood events with over 84 casualties for the period 1926-2013 is presented. Monthly distribution of registered torrential floods indicates that the majority of events with the highest share of death toll occurred in the late spring, from May to the end of June. According to the annual distribution there is a linear increase of torrential flood occurrence in the course of 88 years, but decrease of death toll is found. The greatest number of torrential flood events and casualties is registered in the Južna Morava river basin (watersheds of Nišava, Toplica, Veternica, ). The results of this work can be of great value in the implementation of the Flood Directive of the European Commission on a river basin level as well as for the future natural hazards information system in Serbia. Key words: torrential floods, spatiotemporal distribution, Zapadna Morava, Južna Morava, Velika Morava.

INTRODUCTION Torrent network at the territory of Serbia numbers more than 12000 torrents (Kostadinov et al., 2006), mostly phenomenon have made many countries in the world suffer The frequency and magnitude of the torrential flood Morava river basins due to relief dissection as well as extent the large human and economic losses in the recent period situated in the Južna Morava, Zapadna Morava and Velika (Hershy, 2005; Münchener Rückversicherungs-Gesellschaft, 2009; Marchi et al., 2010; Gourley et al. 2010, Shao et al., of area. The most striking torrential flood in the course of 2014; Wang et al., 2015; Abbas et al the 80ies occurred in Lještarska dolina (Južna Morava, July are the frequently reccuring water-related natural hazard in 1982), Sejanička (Južna Morava, July 1983), Lugomir (Velika ., 2015). Torrentialet al., 2011a; floods inMorava, studied February river basins 1986) happened and Vlasina in watersheds (Južna Morava, of Lugomir, June et al., et al., 2013; Kostadinov 1988) watersheds. Recent large-scale torrential flood events etSerbia al., 2014).that deserves This kind a special of natural attention hazard (Ristić is related to the Dragićević 2011; Dragićević hilly-mountainous regions in Serbia, on the territory south Gruža, Jasenica and Lepenica in July 1999 (Velika Morava, of the Sava River and the River, endangered by eight fatalities), Resava in June 2002 (Južna Morava, one intensive soil erosion processes, having as a consequence death), Vlasina in November 2007 (Južna Morava). Although the extreme flood events in April and May 2014 occurred mainly in north-western part of Serbia, flood events in specific hydrological and sediment transport regime in the noticed material damages. occurs after a short-duration heavy rainfall as a sudden , Požega and Lučani in the Morava river basin left appearancetorrential riverbeds of maximal (Petrović, discharge 2014). with Torrential a high concentration flood wave of erosion sediment lasting from one to several hours events in Serbia were analysed, mostly they are poorly et al., 2012; Garambois et al., 2014). Torrential documentedHowever, a smalland mainly number described of historical with some torrential photos flood and rare measured data. Although population and local economy mean(Ristić discharge having destructive energy. However, these extremesflood wave are discharge mostly ungauged can be larger despite than the 1000 need times of special than basin, there was no centralized and consistent collection kind of surveying (Borga et al., 2008). is highly affected by torrential floods in the Morava river in several developed countries which contribute to better 1 of data on torrential floods. Databases on natural hazards [email protected] Đure Jakšića 9, 11000 Belgrade, Serbia understanding of torrential floods as extreme hydrological

64 spatium Petrović M. A., Ristić R.

: Spatiotemporal review of the torrential flood phenomenon in the Morava river basin hazards, records this phenomenon for the past several studies with detailed analysis of past events. Absence of centuries (Swiss database on natural hazards numbers data and reports on torrential events in archives of public over 20,000 events; Austrian database on natural hazards organizations on the state and local level mainly impeded numbers about 28,000 events, of which torrent events share them to contribute to this dataset. Method for building th century) et al., 2014). The purpose of this work is to present spatial and time framework and needed parameters, after is over 20000; the first record is situated in the 6 the insightsdataset consists into data of availability, five important (2) data steps: collection, (1) defining (3) basin(Petrović through spatiotemporal characterization of historical organizing data, (4) data analysis, (5) data publishing, a phenomenon of torrential floods in the Morava river et al., 2015). Collection of intorrential accordance flood with events the Europeanin order to Union give Floodcontribution Directive. to the Tabledistribution 1) facilitated and use (Petrović analysis of spatial and temporal improvement of the torrential flood policy which should be minimum data (as shown in an example of river Koritnička, METHODOLOGY basin. The research question of data analysis consists in examiningdistribution the of torrential trend changes flood eventsof frequency in the Morava of torrential river Study area The research focus is on the greatest “national” river basin localities with material damages and casualties. in Serbia (Figure 1), which is mostly hilly-mountainous area, flood occurrence as well as in exploring the most frequent Table 1. An example of minimum data for registering torrential flood event the Serbian territory and homes of 53% of population are situatedwith the within.confluence According to the Danubeto the Water River. Management It covers 41.5 Plan % of river basin (A=15,465 km2), 19,110 ha in the Zapadna theMorava Republic river of basin Serbia (A=14,653 (2001), 38,890 km2) ha and in 26,400the Južna ha Morava in the Velika Morava river basin (A=6,810 km2) are potentially meteorological extremes, geological and soil properties flooded area of a return period of 100 years. Beside changes and topography are the direct factors of torrential regimesunfavourable of water for waterdischarges, infiltration, i.e. disbalanced deforestation, ratio betweenland use high and low waters in watersheds of torrential tributaries in the Morava river basin.

meteorological (rainfall quantity and duration), hydrological (dischargeRare torrential and water flood level) events and were sediment recorded transport with data. full Mainly they are modestly documented. For example, in the case of information about an affected location, but not the

intorrent, scale 1:25,000for identification (printed ofby micro-torrential Military Geographic catchment Institute, as 1980)a subject for of the flood whole event, area geo-referenced of the Morava topographic river basin maps were used. Therefore, affected locations are given geographic coordinates in this database becoming geospatial data on natural hazards.

RESULTS

river basin dates from the sixteenth century and refers to the One of the oldest records of torrential flood events in studiedth

floodfound of in the monastery Raška river chronicles (Zapadna datingMorava from river XVIII basin) and on 18 XIX centuryMay in 1518 representing (Šakota, introductory1989). Some historicalflood descriptions information were of

Figure 1. Study area – Morava river basin this dataset. Dataset consists of data on the torrential floods Materials and methods during XX century up to date. The first data in the previous incentury “torrential” we avail 1929 is the in May,torrential June andflood August. of the Skrapež in May 1926. The following 20 torrential flood events were located river basin is derived from newspaper articles gathered The dataset of torrential flood events in the Velika Morava 479 events with over 84 casualties for the period 1926-2013. (1975), archival documentation of the newspaper “Politics” Dataset on torrential floods in the Morava river basin records for the periodperiod fromfrom 19701926 toto 20131970 andin the data book from by papers Gavrilović and The largest number of torrential flood events and casualties took place in the Južna Morava river basin (Figure 2) which

spatium 65 Petrović M. A., Ristić R.

: Spatiotemporal review of the torrential flood phenomenon in the Morava river basin is a result of an inadequate soil management, extreme forest exploitation and destruction and intensive soil theoretical probability function is given in this work for erosion processes (i.e. inadequate watershed management) Hydrological statistical analysis according to the most fitted having as a consequence severe economical damages in watersheds in the Morava river basin (Table 2) which are naturallysome examples characterized of extreme by torrential extreme flood discharges events of with selected high return period (T) and low probability of occurrence (P). The agriculture and traffic (for example, many times in history randomness of time series of maximum annual discharges registereddamaged international in watersheds routes of the Belgrade Ibar (Z. Morava),- Atina and the - NišavaSofia). is tested by methods of Newman and Wald-Wolfowitz. The (J.The Morava), greatest the number Jasenica of torrential (V. Morava) floods and in the sub-basins Veternica is homogeneity of average values is tested by Student test, (J. Morava). Spatial distribution of the most destructive dispersion homogeneity by Fisher test and distribution function by Wilcoxon test. Theoretical probability death tolls in the Morava river basin is given in Figure 3. distribution functions: Normal, Log-Normal, Gumbel, Accordingtorrential floodto distribution events in of terms locations, of material it can damagesbe concluded and Pearson III and Log-Pearson III are calculated. Kolmogorov- Smirnov and Kramer-Mizes tests are applied for concordance between empirical and theoretical distribution which tothat greater material rivers. damages in the Južna and Zapadna Morava decided on the most competent theoretical probability river basins are the greatest at the confluence of the torrents distribution. Watershed E DT E=127 (26%) Distribution of registered events within a year (Figure 4) Ibar 49 10 DT=12 16 - or 33.2%) and May (96 or 20%), followed by July (57 or E=157 (33%) ĐetinjaLepenica 21 4 11.9%),indicates February that the majority (40 or 8.4%)of floods and occurred March in (33 June or (E=159 6.9%). DT= 11 E=195 (41%) Nišava 43 - Therefore, two peaks can be distinguished: the primary DT>61 Veternica 26 -

Jablanica 17 3 year (June and May) and the secondary peak in the colder peak of torrential flood occurrence in warmer part of the Toplica 19 - part of the year (February and March). Monthly distribution

Lepenica 21 4 of the rainfall regime in hilly-mountainous regions in Serbia Zapadna Morava Velika Morava Jasenica 27 3 of registered torrential floods greatly corresponds to peaks

FigureJužna Morava 2. Number of torrential flood events (E) and death toll (DT) per the area of frequency of maximal discharges in torrential river basin and selected watersheds as well as to the earlieret al. domestic findings of research in of occurrence of the maximal discharges south of the Sava watersheds. Ristić (2009) defined two critical periods half of June) and secondary at the end of winter (February and the Danube - primary at the end of spring (May & first

& first half of March). This result also corresponds to the findings ofet monthlyal., 2014). distribution of recorded events at the level of the Inventory of torrential flood events in Serbia (PetrovićAccording to annual distribution (Figure 5) for an observed period of 88 years there is a trend of linear increase of number

the basis of number of events are 1969 (E=37), 2005 (34), 1992of torrential (32) and flood 1975 events. (32). The The peak annual years mean distinguished of registered on

torrential flood events for the observed period is 5.4. is noticed in their distribution per periods: 1931-1960 andThe 1961-1990, changes in whichthe frequency are recommended of torrential by theflood Republic events Hydromethorological Service of Serbia to analyze the Figure 3. Locations with the most destructive torrential flood events precipitation and air temperature trend changes, and recorded in the Morava river basin in the period 1926-2013

Table 2. The frequency of occurrence of maximal discharges of extreme torrential floods

3 River basin Year Qmax (m /s) Function P (%) T (yr) Vlasina: Vlasotince 26.06.1988 780 Log-Pearson III 0.89 113 Watershed: Profile J. Morava 20.04.2000 202 Pearson III 0.79 126 12.07.1999 43 Pearson III 1.82 55 Visočica: V. Ržana Z. Morava G.Gruža: Moravica: Guberevac Ivanjica 13.05.1965 362 Log-Pearson III 0.92 109 11.06.2002 242 Log-Normal 0.51 195 V. Morava Crnica: Paraćin 10.07.1999 193 Log-Pearson III 0.54 184 Lepenica: Batočina

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: Spatiotemporal review of the torrential flood phenomenon in the Morava river basin

180 Number of events Death toll in a wide range of intensity in sense of consequences and 160 materialIn the Morava damages river which basin, are torrential inseparable flood part events of the torrentialoccurred 140

120 toflood the phenomenon. suggested categorization Therefore, the of the idea intensity is to show of torrential different 100 stages of torrential floodet evental., 2014). intensity The (Tablehighest 3) number according of recorded historical events belongs to excessive (34%), high 80 flood events (Petrović 60 local(23%) level. and very high intensity (21%), confirming the fact 40 about catastrophic consequences of torrential flood on the 20 Table 3. Categorization of torrential flood events in the Morava river basin

0 Flooded area E Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec CategoryI (excessive of flood intensity) event >500 ha/>100 housing units 165 Figure 4. Monthly distribution of registered events and fatalities II (very high intensity) 101-500 ha/51-100 housing units 101 40 III (high intensity) 51-100 ha/21-50 housing units 110 Number of events Death toll 35 IV (medium intensity) 21-50 ha/6-20 housing units 59 V (low intensity) <20 ha/1-5 housing units 44 30

25 However, even when the ability to forecast events and 20

15 recentwarn population years is also at noticed, risk in modernwhich is flood a result risk of managementcombination 10 ofsystems a higher increases, frequency an increaseof the extreme in flash events flood impactand a higherin the exposure of the vulnerable population (Calliano et al., 2013). 5 Due to expected future changes in climate conditions, the 0 increase (Ballesteros-Canovas et al., 2015).

1925 1928 1931 1934 1937 1940 1943 1946 1949 1952 1955 1958 1961 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009 2012 adverse impacts of flash floods could unfortunately further Figure 5. Annual distribution of registered events and casualties in the CONCLUSIONS observed period with trend lines

in the Morava river basin, there are four main conclusions: According to the analysis of dataset of torrential flood events frequencyremaining, inthe the first last period two fromperiods 1915 (averages to 1930 andof numberthe last period from 1990 to 2013. The increase of torrential flood belonging1) The greatest sub-basins number of Nišava, of torrential Veternica, floodToplica, events Jablanica. and 1991-2013 are 7.3 and 6.3 respectively, in comparison with 2)casualties The primary are registered maximum in therefers Južna to Moravasummer river months, basin June and torrential flood events per year for periods 1961-1990 and and May and the secondary maximum refers to winter goes in line with the data from the literature about high months, February and March (which is triggered not only averages for the first period a=1.3 and the second one a=3.2) increase in average annual hydrological natural hazards in by strong showers but also coincidence of rain showers with sudden snow melting), according to intra-annual et al., 2011; Llaset et al. et al., 2014; Modrick frequency analysis. 3) The highest death toll of registered etthe al. world per decade (Abbott, 2008; Munich Re, 2009; Ristić 2014; Petrović decrease of death toll per period (average for II period is their occurrence, i.e. summer months June, May and July. , 2015; Petrović, 2015a). Although there is a linear 1.5 deaths, IIIa=0.9, IVa=0.7), there is still a need for risk 4)torrential In terms flood of the events extent followsof material the damages, primary maximumthe excessive of high mortality rate account more than 5000 deaths annually common. oneducation a global of basis affected (Jonkman, local population.2005). Considering Flash floods the number with a intensity or I category of torrential flood events is the most Therefore, well-structured and systematic dataset of top natural hazards in Serbia so that the following data shouldof fatalities draw and attention people to affected, the improvement the torrential in prevention floods are historical torrential flood events for each river basin enabling riskdata management analysis and and leading integrated to valuable river basin findings management. can be of 1939and response (28 deaths), of the 1975 torrential (12), 1937 flood (eight), risk management 1956 (eight) cycle and Althoughgreat importance there forwas decision no centralized making in thedocumentation torrential flood of 1999(Petrović, (eight) 2015b). and peakIn terms months of death are toll,June the (26 peak deaths), years May are previous period, this gap should be overcome in decades to come.torrential flood phenomenon on the national level in (17) and October (17). Top torrential flood events in terms Juneof fatalities 1939 (11). took place in Koritnička river - October 1939 (17 deaths), Korbevačka river - May 1975 (12), Selska river -

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: Spatiotemporal review of the torrential flood phenomenon in the Morava river basin

Acknowledgement Torrential Floods in Serbia - Characteristics and Possibilities This work is supported by the Ministry of Education, Science Kostadinov, S., Borisavljević, A., Mlađan, D. (2014) TorrentsAdvances and in and Technological Development of the Republic of Serbia GeoEcology. Reiskirchen: Catena Verlag, pp. 156-172. under Grant 47007 III. Llasat,of its Control,M. C., Marcos, in Zlatić, R., M. Llasat-Botija, and Kostadinov, M., S. Gilabert, (eds.) J., Turco,

REFERENCES Western Mediterranean, Atmospheric Research, Vol. 149, pp. Abbas, A., Amjath-Babu, T. S., Kächele, H., Müller, K. (2015) Non- 230–243.M., Quintana-Seguí, P. (2014) Flash flood evolution in North- Marchi, L., Borga, M., Preciso, E., Gaume, E. (2010) conditions: an analysis on the determinants of willingness to structural flood risk mitigation under Natural developing Hazards, country Vol. Journal of 75, No. 3, pp. 2119-2135. Hydrology,Characterisation Vol. 394, of No. selected 1-2, pp. extreme 118-133. flash floods in Europe pay for flood insurance in rural Pakistan, Abbott, P. L. (2008) Natural Disaster. New York: McGraw-Hill Modrick,and implications T. M., Georgakakos, for flood K. risk P. (2015) management, The character and Science/Engineering/Math. Ballesteros-Canovas, J. A., Czajka, B., Janecka, K., Lempa, M., basins of Southern California under projected climatic change, Journalcauses of of flash Hydrology: flood occurrence Regional Studies, changes Vol. in mountainous3, pp. 312–336. small Mountain streams: Frequency and triggers, Science of The Münchener Rückversicherungs-Gesellschaft (2009) Geo Kaczka, R. J., Stoffel, M. (2015) Flash floods in the Tatra Total Environment, Vol. 511, pp. 639–648. Natural Catastrophes 2008: Analyses, Assessments, Positions, Borga, M., Gaume, E., Creutin, J. D., Marchi, L. (2008) Surveying Munich. Hydrological Factors of torrential flood occurrence in Processes, Vol. 22, No.18, pp. 3883–3885. Serbia. Belgrade: Faculty of Forestry, University of Belgrade, flash floods: gauging the ungauged extremes, Petrović, A. M. (2014) Journal of Hydrology, Calianno,Vol. 477, M., pp. Ruin, 1–16. I., Gourley, J. J. (2013) Supplementing flash Doctoral dissertation, 207 pp. [Petrović, A. M. (2014a) Faktori flood reports with impact classifications, nastanka bujičnih poplava u Srbiji. Beograd: Šumarski fakultet, andUniverzitet Characterization u Beogradu, of Doktorska Torrential disertacija, Flood Phenomenon 207 str.] in Dragicević,S. (2011) NaturalS., Filipović, hazard D., Kostadinov,assessment S.,for Ristić, land-use R., Novković, planning inI., Petrović,Serbia, PolishA., Kostadinov, Journal of S., Environmental Dragićević, S. Studies(2014), TheVol. Inventory23, No. 3, Serbia.Živković Intternational N., Andjelković, Journal G., Abolmasov, of Environmental B., Šećerov, Research V., Đurđić,, Vol. pp. 823-830. 5, No. 2, pp. 371-380. Z. (2015) Historical Torrential Flood Events in the Petrović,River Basin. A. M., Natural Dragićević, Hazards, D. S., Vol. Radić, 79, No.B. P., 1, Milanović pp. 537-547. Pešić, A. Dragićević,in 2010 – Case S., Ristić, Study: R., The Živković, Kolubara N., and Kostadinov, Pcinja River S., Basins, Tošić, R.,in Loczy,Novković, D. (ed.) I., Borisavljević, Geomorphological A., Radić, impacts Z. (2013) of extreme Floods inweather: Serbia Morava River Basin, IInd International Conference „Natural Case studies from central and eastern Europe, Heidelberg: Petrović,Hazards A.– M.Links (2015a). between Torrential Science floodand eventsPractice“, in Saransk the Južna - Springer Geography, pp. 155-170. Russia, Proceedings, pp. 356-362. Garambois, P. A., Larnier, K., Roux, H., Labat, D., Dartus, D. management, Journal of Geographical Institute “Jovan Cvijić” oriented hydrological model, Atmospheric Research, Vol. 137, Petrović,of the Serbian A. M. Academy (2015b). of ChallengeSciences and of Arts torrential, Vol. 65, flood No. 2, risk pp. pp.(2014) 14–24. Analysis of flash flood-triggering rainfall for a process- 131-143. Bujični tokovi u SR Srbiji. Belgrade: maximal discharges on torrential watersheds in Serbia. Gavrilović, S. (1975) Torrents Ristić, R., Radić, B., Vasiljević, N. (2009) Vol. Characteristics89, No. 4, pp. 161- of inRepublički Serbia. Belgrade: fond voda, Republic Institut Water za vodoprivredu Fund and Institute erozionih of Bulletin of Serbian Geographical Society, područja Šumarskog fakulteta. [Gavrilović, S. (1975) 189. Gourley, J. J., Erlingis, J. M., Smith, T. M., Ortega, K. L., Hong, Y. (2010)erosion Remotearea management collection andof the analysis Faculty of of witness Forestry]. reports on Ristić, R., Radić, B., Nikić, Z., Trivan, G., Vasiljević, N., Dragićević, Journal of Hydrology, Vol. 394, No. 1–2, pp. 53-62. SPATIUMS., Živković,, No. N., 25, Radosavljević, pp. 1-6. Z. (2011a) Erosion control and protection from torrential floods in Serbia - spatial aspects, Flowflash Measurementfloods, and Instrumentation, Vol. 13, pp. 231–235. Herschy, R. W., (2005) The world’s maximum observedVodoprivrednа floods, Ristić,restoration R., Radić, of the B., Vasiljević,river Jelašnica N., Nikić, watershed, Z. (2011b) Bulletin Land of use the osnovа Republike Srbije. change for flood protection - a prospective study for the Institut zа vodoprivredu „Jаroslаv Černi“ (2001) Faculty of Forestry, No. 103, pp. 115-130. Institute for the Development Beogrаd:of Water Resources Ministаrstvo (2001) zа Waterpoljoprivredu, Management šumаrstvo Plan of ithe vodoprivredu. Republic of Serbia [Jaroslav. Belgrade: Černi Ministry of agriculture, forestry and water management of the Ristić,12th Congress R., Kostadinov, Interprävent, S., Radić, Grenoble B., Trivan, - France, G., Nikić, Proceedings, Z. (2012) pp.Torrential 771-779. floods in Serbia – man made and natural hazards, Jonkman, S. N. (2005) Global perspectives on loss of human life Republic of Serbia.]Natural Hazards, Vol. 34, No. 2, pp. 151–175. pisanim izvorima od XIII do XIX veka, JUSOP, – Šakota V. (1989): Tragom zapisa o poplavama prema srpskim caused by floods, Serbia and Montenegro, in Boardman, J. and Poesen J. (eds.) Srbija. Zbornik radova, pp. 274-282. [Šakota, V. (1989) Track Kostadinov, S., Zlatić, M., Dragović, N., Gavrilović, Z. (2006) century, the JUSOP Conference, Kopaonik: Serbia. Proceedings, Soil Erosion in Europe. Chichester: John Wiley & Sons, pp. records of floods according to written sources from XIII to XIX 271–279. pp. 274-282.]

68 spatium Petrović M. A., Ristić R.

: Spatiotemporal review of the torrential flood phenomenon in the Morava river basin

Shao, M., Gong, Z., Xu, X. (2014) Risk assessment of rainstorm

Natural Hazards, Vol. 71, No.and 2,flood pp. 1025-1052.disasters in China between 2004 and 2009 based Wang,on gray Z., fixedLai, C., weight Chen, clusterX., Yang, analysis, B., Zhao, S., Bai, X. (2015) Flood hazard risk assessment model based on random forest, Journal of Hydrology, Vol. 527, pp.1130-1141.

Received August 2015; accepted in revised form December 2015.

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