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3. Estimating flash flood peak discharge in Gidra and Parná basin: case study for the 7-8 june 2011 flood

Creator:
Pekárová, Pavla, Svoboda, Aleš, Miklánek, Pavol, Škoda, Peter, Halmová, Dana, and Pekár, Ján
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
flash floods, Gidra and Parná Rivers, post-flood event analysis, runoff modeling, bleskové povodne, rieky Gidra a Parná, analýza povodní, and modelovanie odtoku
Language:
Slovak
Description:
We analyzed the runoff and its temporal distribution during the catastrophic flood events on river Gidra (32.9 km2 ) and Parná (37.86 km2 ) of the 7th June 2011. The catchments are located in the Small Carpathian Mountains, western Slovakia. Direct measurements and evaluation of the peak discharge values after such extreme events are emphasized in the paper including exceedance probabilities of peak flows and of their causal flash rainfall events. In the second part of the paper, plausible modeling mode is presented, using the NLC (Non Linear Cascade) rainfall-runoff model. Several hypothetical extreme flood events were simulated by the NLC model for both rivers. Also the flood runoff volumes are evaluated as basic information on the natural or artificial catchment storage. and Predložený príspevok analyzuje tvorbu a priebeh odtoku počas katastrofickej povodňovej situácie na Gidre (32,9 km2 ) a na Parnej (37,86 km2 ) dňa 7. 6. 2011. Povodia týchto tokov sa nachádzajú v Malých Karpatoch na západnom Slovensku. V príspevku sa kladie dôraz na priame zameranie a vyhodnotenie kulminačných prietokov po výskyte takýchto povodní. Diskutujú sa problémy vyjadrenia pravdepodobnosti prekročenia kulminačných prietokov a dažďov, ktoré ich spôsobili. V druhej časti príspevku je prezentovaný možný spôsob modelovania povodne jednoduchým zrážkovo-odtokovým modelom NLC. Daným modelom NLC sú následne simulované prietoky Gidry v stanici Píla a Parná v stanici Horné Orešany za extrémnej hypotetickej zrážkovej udalosti. Hodnotené sú objemy odtoku počas povodní, ako základný údaj pre reálny odhad ich prirodzeného alebo umelého zadržania.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Historic flood marks and flood frequency analysis of the Danube River at Bratislava, Slovakia

Creator:
Pekárová, Pavla, Halmová, Dana, Bačová Mitková, Veronika, Miklánek, Pavol, Pekár, Ján, and Škoda, Peter
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
historic floods, extreme flood peak, flood hazard, Danube River, and Bratislava
Language:
Slovak
Description:
In this paper we focused on the history of floods and extreme flood frequency analysis of the upper Danube River at Bratislava. Firstly, we briefly describe the flood marks found on the Danube River in the region of Bratislava, Slovakia, and provide an account of the floods’ consequences. Secondly, we analyzed the annual maximum discharge series for the period 1876–2012, including the most recent flood of June 2013. Thirdly, we compare the values of T-year design discharge computed with and without incorporating the historic floods (floods of the years 1501, 1682, and 1787 into the 138-year series of annual discharge peaks). There are unfortunately only a few historic flood marks preserved in Bratislava, but there are very important and old marks in neighbouring Hainburg and other Austrian cities upstream to Passau. The calculated T-year maximum discharge of the Danube at Bratislava for the period 1876-2010 without and with historic flood values have been compared. Our analysis showed that without incorporating the historic floods from the years 1501, 1682, and 1787 the 1000-year discharge calculated only with data from the instrumented period 1876- 2013 is 14,188 m3 s -1 , and it is lower compared to the 1000-year discharge of 14,803 m3 s -1 when the three historic floods are included. In general, the T-year discharge is higher throughout the whole spectrum of T-year discharges (10, 20, 50, 100, 200, 500-year discharge) when the three historic floods are included. Incorporating historic floods into a time series of maximum annual discharge seems to exert a significant effect on the estimates of low probability floods. This has important implications for flood managements and estimation of flood design discharge.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5. Hydrological simulation of flood transformations in the upper Danube River: case study of large flood events

Creator:
Bačová Mitková, Veronika, Pekárová, Pavla, Miklánek, Pavol, and Pekár, Ján
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Danube River, June 2013 flood, hydrological nonlinear river routing model, and catastrophic flood scenario
Language:
Slovak
Description:
The problem of understand natural processes as factors that restrict, limit or even jeopardize the interests of human society is currently of great concern. The natural transformation of flood waves is increasingly affected and disturbed by artificial interventions in river basins. The Danube River basin is an area of high economic and water management importance. Channel training can result in changes in the transformation of flood waves and different hydrographic shapes of flood waves compared with the past. The estimation and evolution of the transformation of historical flood waves under recent river conditions is only possible by model simulations. For this purpose a nonlinear reservoir cascade model was constructed. The NLN-Danube nonlinear reservoir river model was used to simulate the transformation of flood waves in four sections of the Danube River from Kienstock (Austria) to Štúrovo (Slovakia) under relatively recent river reach conditions. The model was individually calibrated for two extreme events in August 2002 and June 2013. Some floods that occurred on the Danube during the period of 1991-2002 were used for the validation of the model. The model was used to identify changes in the transformational properties of the Danube channel in the selected river reach for some historical summer floods (1899, 1954 1965 and 1975). Finally, a simulation of flood wave propagation of the most destructive Danube flood of the last millennium (August 1501) is discussed.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Identification and assessment of long-term trends of surface water quality determinands in Slovakia for implementation of the EU WFD

Creator:
Pekárová, Pavla, Miklánek, Pavol, Rončák, Peter, Adámková, Juliana, Chriašteľ, Robert, Metelková, Miroslava, and Pekár, Ján
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
long-term trends, water quality, WFD 2000/60/EC, Slovak Republic, Hron River, dlhodobé trendy, kvalita vody, smernica 2000/60/EC, Slovensko, and Hron
Language:
Slovak
Description:
The procedure for identification of the long-term trends in the individual water quality determinands in surface water is described in the study. The methodology is based on requirements of the Directive 2000/60/EC and the existing water quality data in the database of the Slovak Hydrometeorological Institute. The methodology gives guidance for estimation of following issues: - influence of the length of the series on trends of development; - methods for calculation of the statistical characteristics; - methods for identification of the increasing and decreasing trends, as well as of the trend reversal point; - selection of the decision criteria for assessment of the trend significance. The methodology was applied for the trend analysis of the selected pollutants in the middle part of Hron River at Salkova near Banska Bystrica city. The results show that the rapid increase of pollution in 1970`s is followed by gradual improvement of the surface water quality in next period. and V predloženej štúdii je opísaný postup pri identifikácii dlhodobých trendov jednotlivých ukazovateľov kvality vody v povrchových tokoch. Pri vypracovaní metodiky sa vychádzalo z požiadaviek smernice 2000/60/EC a z existujúcich údajov o kvalite vody v databáze Slovenského hydrometeorologického ústavu. Vypracovaná metodika navrhuje konkrétne postupy na určovanie, napr. - vplyvu dĺžky obdobia na vývojové trendy; - spôsobov výpočtu štatistických ukazovateľov; - spôsobov identifikácie trendov rastu a poklesu, ako i bodov obratu trendu; - kritérií na rozhodovanie o významnosti jednotlivých trendov. Navrhnutá metodika bola aplikovaná pri analýze vybraných ukazovateľov kvality vody v mieste odberu Hron-Šalková , situovanom pri Banskej Bystrici. Z výsledkov vyplýva, že po prudkom náraste znečistenia stredného Hrona v sedemdesiatych rokoch dvadsiateho storočia dochádza k postupnému zlepšovaniu kvality povrchových vôd v tomto úseku.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

7. Identification of long-term high-flow regime changes in selected stations along the Danube River

Creator:
Pekárová, Pavla, Pramuk, Branislav, Halmová, Dana, Miklánek, Pavol, Prohaska, Stevan, and Pekár, Ján
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
floods, hydrological regime, long streamflow series, Danube River, flow thresholds, and flood trends
Language:
Slovak
Description:
The aim of the paper is to study spatial and temporal changes in the magnitude, duration and frequency of high flows in the Danube basin. A hydrological series of the mean daily discharges from 20 gauging stations (operated minimally since 1930) were used for the analysis of changes in the daily discharges. The high flow events were classified into three classes: high flow pulses, small floods, and large floods. For each year and for each class, the means of the peak discharges, the number and duration of events, and the rate of changes of the rising and falling limbs of the waves were determined. The long-term trends of the annual time series obtained were analyzed and statistically evaluated. The long-term high flow changes were found to be different in three individual high flow classes. The duration of the category of high flow pulses is decreasing at 19 stations on the Danube and is statistically significant at the Linz, Vienna, Bratislava and Orsova stations. The frequency of the high flow pulses is increasing in all 20 stations. Also, the rising and falling rates of the high flow pulse category are increasing at the majority of the stations. The long-term trends of the selected characteristics of the small floods are very similar to the trends of the high flow pulses, i.e., the duration of small floods is decreasing, and their mean number per year is increasing. In the category of large floods the changes were not proved.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

10. Nitrate wash off from the Bratislava Forest Park basin Vydrica in years 1986 - 2005

Creator:
Sebíň, Michal, Pekárová, Pavla, and Miklánek, Pavol
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Vydrica, experimental catchment, nitrate wash of, modelové povodia, and odnos dusičnanov
Language:
Slovak
Description:
In the model catchment Vydrica brook in Small Carpathians (mostly beech forest), concentrations of the selected chemical substances were monitored for evaluation of the land use impact upon the brook water quality. Concentrations of these substances were monitored within the years 1991-1993. In order to evaluate also a development of the long-term trend of the observed data, we are continuing in their monitoring since 2004. In this paper there are evaluated nitrate concentrations from two localities: in the upper Vydrica part (Spariská), and on the Bratislava city area limit (Červený Most), in the Vydrica lower part. The mean nitrate concentration in 1991-1993 at Spariská was 14.54 mg l-1, at Červený Most locality 10.84 mg l-1, in the years 2004-2005 the mean concentration at Spariská it was 11.85 mg l-1, and 9.36 mg l-1 at Červený Most. From the observed data it follows that in the 2004-2005 years the nitrate concentration dropped in comparison with the 1991-1993 period. As there was a significant relationship documented between the nitrate concentration and discharge, the empirical relationships were developed for estimating of daily nitrate concentration values based on the mean daily discharges, for the 1987-2005 period. From these, then the mean monthly and yearly nitrate wash offs were calculated from the unit area. So for the Spariská subcatchment the mean yearly nitrate wash off range was 15.42 to 102.37 kg ha year-1, for the profile Červený Most it was 9.01 to 70.53 kg ha year-1. and V modelovom povodí potoka Vydrica v Malých Karpatoch (prevažne bukový les) boli sledované koncentrácie vybraných chemických látok v povrchovom toku za účelom hodnotenia vplyvu využitia krajiny na kvalitu vody v toku. Koncentrácie týchto látok sme sledovali v rokoch 1991-1993. Aby sme zhodnotili dlhodobý trend vývoja nameraných údajov, od roku 2004 v monitoringu pokračujeme. V tomto príspevku sú zhodnotené koncentrácie dusičnanov na dvoch lokalitách: v hornej časti Vydrice (Spariská) a na hranici s hlavným mestom Bratislava (Červený Most) v dolnej časti povodia. Priemerná koncentrácia dusičnanov v rokoch 1991-1993 bola na lokalite Spariská 14,54 mg l-1, na lokalite Červený Most 10,84 mg l -1, v rokoch 2004-2005 bola priemerná koncentrácia na lokalite Spariská 11,85 mg l-1 a na Červenom Moste 9,36 mg l-1. Z nameraných hodnôt vyplýva, že v porovnaní s obdobím rokov 1991-1993 v rokoch 2004-2005 došlo k poklesu koncentrácií dusičnanov. Keďže sa preukázala významná závislosť medzi koncentráciami dusičnanov a prietokmi, odvodili sme empirické vzťahy na nepriamy odhad denných hodnôt koncentrácií dusičnanov na základe meraných priemerných denných prietokov za obdobie rokov 1987-2005. Z vypočítaných denných koncentrácií dusičnanov boli vypočítané priemerné mesačné a ročné odnosy dusičnanov z jednotky plochy. V podpovodí Spariská sa ročné odnosy dusičnanov pohybovali od 15,42 kg ha-1 rok-1 do 102,37 kg ha-1 rok-1, v profile Červený Most od 9,01 kg ha-1 rok-1 do 70,53 kg ha-1 rok-1.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public