Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 3 - 9, doi: 10.31577/ahs-2019-0020.01.0001
Scientific Paper, Slovak

Hana Hlaváčiková, Michaela Bírová, Eva Kopáčiková: Estimation of instantaneous peak flows from mean daily flows

 Full Text in PDF     88 DOWNLOADS

• Instantaneous peak flows are needed for several water management tasks. However, they are not always available. More disponible are often mean daily flows. In this work, relationship between instantaneous peak flows and mean daily flows for 26 Slovak water gauging stations was estimated according to two methods. The first method was the simple linear-regression method (LR method), the second one was the so-called slope-based method (Chen method) which is based on an analysis of three consecutive mean daily flows and takes into account the hydrograph shape. Results showed that the LR method is for given water gauging stations comparable to the Chen method. The LR method provides an instantaneous peak flow estimation with a mean relative error in the range of 1.8–19.8% (the smallest error is for large basins). Moreover, for all water gauging stations, the LR conversion factors (instantaneous peak over maximum mean daily flow ratio) were derived. Resulting values varied between 1 for large watersheds, up to 1.3 to 1.6 for smaller watersheds, for which higher flow variability is typical
  
  KEY WORDS: hydrograph, linear-regression, water gauging stations, basin area
  
  Address:
  - Hana Hlaváčiková, Slovenský hydrometeorologický ústav, Jeséniova 17, 833 15 Bratislava 37 (Corresponding author. Tel.: Fax.: Email: hana.hlavacikova@shmu.sk)
  - Michaela Bírová, Slovenský hydrometeorologický ústav, Jeséniova 17, 833 15 Bratislava 37
  - Eva Kopáčiková, Slovenský hydrometeorologický ústav, Jeséniova 17, 833 15 Bratislava 37

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 10 - 21, doi: 10.31577/ahs-2019-0020.01.0002
Review, Slovak

Mária Ďurigová, Kamila Hlavčová, Magdálena Komorníková, Jana Kalická, Dominika Ballová, Tomáš Bacigál: The change analysis of the mean monthly discharges in Slovakia in recent decades

 Full Text in PDF     80 DOWNLOADS

• An analysis of a hydrometeorological time data series is an important part in assessing changes in hydrological processes. Understanding changes in time series results in a better understanding of the causes of these changes. A time data series can be evaluated by a large number of analyses. One of them is the application of statistical methods. The article deals with a basic analysis of the mean monthly, annual, and seasonal discharges in selected stage-discharge gauging stations in Slovakia using statistical methods. The time data series were subjected to basic descriptive statistic, trend and periodicity analyses, and AR-ARCH model. These methods were applied to five larger basins in Slovakia and seven smaller basins located in the northern part of the Váh River basin. The results show greatest changes (in trend and periodic analysis) in the Hron River. From the smaller river basins, especially Kysuca and Bystrica River, there are statistically significant decreasing trend
  
  KEY WORDS: the statistical methods mean monthly discharges, trend analysis, AR-ARCH model
  
  Address:
  - Mária Ďurigová, Katedra vodného hospodárstva krajiny, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava 1 (Corresponding author. Tel.:+421 944 067 099 Fax.: Email: maria.durigova@stuba.sk,)
  - Kamila Hlavčová, Katedra vodného hospodárstva krajiny, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava 1
  - Magdálena Komorníková, Katedra matematiky a deskriptívnej geometrie, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava 1
  - Jana Kalická, Katedra matematiky a deskriptívnej geometrie, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava 1
  - Dominika Ballová, Katedra matematiky a deskriptívnej geometrie, Stavebná fakulta, Slovenská technická univerzita v Bratislave,Radlinského 11, 810 05 Bratislava 1
  - Tomáš Bacigál, Katedra matematiky a deskriptívnej geometrie, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava 1

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 22 - 31, doi: 10.31577/ahs-2019-0020.01.0003
Scientific Paper, Slovak

Jakub Mészáros, Pavla Pekárová, Ján Pekár, Katarína Melová: Estimation of T-year flows using a regional skewness coefficient of Log-Pearson type III. Distribution

 Full Text in PDF     73 DOWNLOADS

• Despite the significant development of statistical methods for determining the parameters of theoretical distribution functions, the estimation of T-year flood discharges remains a complex problem, burdened by various uncertainties. The floods that have hit (not only) Slovakia last decades (1997, 1999, 2006, 2010) have led to the admission of an EU flood directive, in which it is necessary to estimate T-year flood values with very long time of repetition (200-1000 years). In the submitted paper we test the method of processing of design values based on statistical processing of the time series of maximum annual peak flows. In estimating the T-year values, we test the use of the log-Pearson type III distribution (LP3). We present the results on the streams of the region in the Slovak part of the Morava river basin. Regional skewness coefficient Gr of log-Pearson type III distribution in the Morava river basin were estimated at 0.38. Although the accuracy of estimating T-year flow rates has been improved by using the regional coefficient, there is still a high uncertainty in estimation of design values for long time of repetition.
  
  KEY WORDS: floods, T-year values, LP3 distribution
  
  Address:
  - Jakub Mészáros, Ústav hydrológie SAV, Dúbravská cesta č. 9, 841 04 Bratislava (Corresponding author. Tel.: Fax.: Email: jakubmeszaros@uh.savba.sk)
  - Pavla Pekárová, Ústav hydrológie SAV, Dúbravská cesta č. 9, 841 04 Bratislava
  - Ján Pekár, Univerzita Komenského v Bratislave, Fakulta matematiky, fyziky a informatiky, Katedra aplikovanej matematiky a štatistiky, Mlynská dolina, 842 48 Bratislava
  - Katarína Melová, Slovenský hydrometeorologický ústav, Odbor kvantity povrchových vôd, Jeséniova 17, 833 15 Bratislava

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 32 - 43, doi: 10.31577/ahs-2019-0020.01.0004
Scientific Paper, Slovak

Veronika Bačová Mitková: The peak over threshold method and its uncertainty in determining of T-year maximum discharges: Case study at the Topľa River

 Full Text in PDF     67 DOWNLOADS

• The paper deals with the comparison of the two most commonly used methods in estimating of the T-year maximum discharges. As input data a set of daily discharges and peak discharges on the Topľa River for the period of 1931–2015 was used. The method of maximum annual discharges (AM) with the most used theoretical probability distributions (Log-Pearson III, Gamma and Log-normal), was used for estimating of T-year maximum discharges. As an alternative to this method, the Peak Over Threshold Method (POT) was used. We analysed the effect of the threshold level selection and using of maximum daily discharges on the accuracy of T-year maximum discharges estimation. We also analysed suitability of selected types of theoretical probability distributions for the accuracy of the T-year maximum discharges estimated using the POT method.
  
  KEY WORDS: Topľa River, maximum mean daily discharge, peak discharge, Peak Over Threshold method, T-year discharge
  
  Address:
  - Veronika Bačová Mitková, Ústav hydrológie SAV, Dúbravská cesta č. 9, 84104 Bratislava (Corresponding author. Tel.: Fax.: Email: mitkova@uh.savba.sk)

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 44 - 52, doi: 10.31577/ahs-2019-0020.01.0005
Scientific Paper, Slovak

Gabriel Földes, Silvia Kohnová, Marija Mihaela Labat: Future changes in seasonality and scaling exponents of short-term rainfalls in the Western Slovakia using CLM scenario

 Full Text in PDF     65 DOWNLOADS

• The study focuses on the analysis of the future changes in characteristic of short term rainfall in the region of Western Slovakia. The analysis was performed for 3 climatological stations namely Bratislava, Hurbanovo and Myjava. For the analysis, the real measured rainfall depths for the period 1995–2009 and the rainfall depths from CLM scenario for period 2070–2100 were used. Analysis was performed for rainfall durations 60 up to 1440 minutes. The Burn´s vector methodic was used for estimation of seasonality changes. For the trend testing the MannKendall test was used. Finally scaling exponents were estimated by using simple scaling method and IDF lines were derived for the analyzed periods. The results of the analysis will provide further information about future changes that we can expect at the end of the century.
  
  KEY WORDS: rainfall depth, short-term rainfall intensities, Burn´s vector, Mann-Kendall trend test, simple scaling
  
  Address:
  - Gabriel Földes, Katedra vodného hospodárstva krajiny, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava 1 (Corresponding author. Tel.:+421 902 681 422 Fax.: Email: gabriel.foldes@stuba.sk)
  - Silvia Kohnová, Katedra vodného hospodárstva krajiny, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava 1
  - Marija Mihaela Labat, Katedra vodného hospodárstva krajiny, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava 1

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 53 - 62, doi: 10.31577/ahs-2019-0020.01.0006
Scientific Paper, English

Pavla Pekárová, Ján Pekár, Pavol Miklánek: Effect of water on bimodality of air temperature distribution functions and changes in T-year air temperature values in Hurbanovo

 Full Text in PDF     64 DOWNLOADS

• Variability and long-term trends in air temperature are in the interest of hydrologists in recent decades as they can affect the global hydrological cycle and water balance in river basins. The estimation of the T-year minimum and maximum mean daily air temperature is associated with the problem of selection of the distribution functions of these series. The histograms of the daily air temperature series manifest the two-peak (bimodal) shape in many stations all over the world. It is not feasible to describe the distribution function of bimodal distribution through single mean value and single standard deviation. In the present study the T-year values of air temperature are estimated for three temperature indexes in station Hurbanovo: 1. series of maximum mean daily air temperature of the year Td,max, 2. series of mean annual air temperature of the year Td; and 3. series of minimum mean daily air temperature of the year Td,min. Change in the theoretic distribution curve of the mean daily air temperature indexes is compared during two subperiods of the instrumental period 1872–2017. Generally, the changes in temperature design values are more marked in case of minimum temperatures, e.g. the value of 100-year minimum mean daily air temperature increased by more than 5°C. The 100-year maximum mean daily air temperature increased by 1.88°C in Hurbanovo
  
  KEY WORDS: air temperature, Hurbanovo, bimodal distribution, T-year values
  
  Address:
  - Pavla Pekárová, Ústav hydrológie SAV, Dúbravská cesta č. 9, 841 04 Bratislava (Corresponding author. Tel.: Fax.: Email: pekarova@uh.savba.sk)
  - Ján Pekár, Katedra aplikovanej matematiky a štatistiky, Fakulta matematiky, fyziky a informatiky UK, Mlynská dolina, 842 48 Bratislava
  - Pavol Miklánek, Ústav hydrológie SAV, Dúbravská cesta č. 9, 841 04 Bratislava

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 63 - 73, doi: 10.31577/ahs-2019-0020.01.0007
Scientific Paper, Slovak

Peter Šurda, Peter Rončák, Justína Vitková, Andrej Tárnik: Regional drought assessment based on the meteorological indices for locality Nitra

 Full Text in PDF     75 DOWNLOADS

• In recent years the droughts have become more severe as a result of climate change. The ability to monitor drought conditions and assess its risk is essential for an effective drought adaptation plan, especially in agricultural ecosystems. Drought indices allow characterization of drought occurrence and extent. The most widely used is the Standardized Precipitation Index (SPI), which is recommended by the World Meteorological Organization as the standard drought index. Although the main cause of drought is lack of rainfall, recent studies have also pointed out the significant role of air temperature and evapotranspiration. The aim of the work was to determine the monthly values of the meteorological drought indexes of the research site Nitra in the period 2014–2018 and to analyze their sensitivity based on the comparison of the determined droughts frequency. We used indexes: SPI (Standardized Precipitation Index), PNI (Percent of Normal Index), DI (Deciles index), MCZI (Modified CZI) and ZSI (Z-score Index), which take into account the values and distribution of daily precipitation amounts. The secondary aim of the work was to analyze and statistically confirm the relationship between daily EDI (Effective Drought Index) and in daily interval measured moisture content of the top soil of the research site, i.e. to confirm the possibility of using EDI to signal the soil drought risk
  
  KEY WORDS: meteorological indices of drought, soil drought, Nitra
  
  Address:
  - Peter Šurda, Ústav hydrológie SAV, Dúbravská cesta 9, 841 04 Bratislava (Corresponding author. Tel.:+4212 3229 3520 Fax.: Email: surda@uh.savba.sk)
  - Peter Rončák, Ústav hydrológie SAV, Dúbravská cesta 9, 841 04 Bratislava
  - Justína Vitková, Ústav hydrológie SAV, Dúbravská cesta 9, 841 04 Bratislava
  - Andrej Tárnik, Katedra biometeorológie a hydrológie, Fakulta záhradníctva a krajinného inžinierstva SPU v Nitre, Hospodárska 7, Nitra

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 74 - 79, doi: 10.31577/ahs-2019-0020.01.0008
Scientific Paper, English

Justína Vitková, Peter Šurda: Soil moisture changes after biochar application in 2018

 Full Text in PDF     52 DOWNLOADS

• Biochar, a product of thermal degradation of biomass, helps to improve the hydrophysical properties of the soil. It works at soils with low quality primarily but its use in conventional agricultural temperate soils has often different effect and depends mainly on the material from which the biochar is produced, the process of pyrolysis, the soil to which the biochar is applied and last but not least, the cultivated crop. In this paper, we deal with changes in silt-loam soil moisture at plots with applied biochar in amount of 20 t/ha and at plots without biochar in 2018. The cultivated crop was spring barley (Hordeum vulgare L.) during the monitoring period June–July 2018. Soil moisture was measured by 5TM sensors. The results confirmed the conclusions of a number of scientific studies that soil moisture was higher at plots with biochar at about 3–8% vol. than at plots without biochar application
  
  KEY WORDS: biochar, soil moisture, spring barley
  
  Address:
  - Justína Vitková, Ústav hydrológie SAV, Dúbravská cesta 9, 841 04 Bratislava (Corresponding author. Tel.:+421 2 3229 3519 Fax.: Email: vitkova@uh.savba.sk)
  - Peter Šurda, Ústav hydrológie SAV, Dúbravská cesta 9, 841 04 Bratislava

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 80 - 88, doi: 10.31577/ahs-2019-0020.01.0009
Scientific Paper, Slovak

Michaela Danáčová, Radovan Nosko, Marcela Maliariková, Miroslav Kandera, Roman Výleta: Comparison of saturated hydraulic conductivity estimated by laboratory and empirical method of Špaček

 Full Text in PDF     65 DOWNLOADS

• Saturated hydraulic conductivity characterizes the conductivity ratios of the soil layers of different areas. It is an important parameter in the mathematical modelling of the soil water regime. Its measurement and detection are one of the most important tasks in solving problems related in the soil hydrology. This paper deals compare two methods of determination of the saturated hydraulic conductivity obtained by a) the laboratory method, b) empirical method according to Špaček. These methods were applicated in Myjava – Turá Lúka and Záhorie – Veľké Leváre, on the west locations in Slovakia. The obtained values of K from laboratory and empirical methods were evaluated and compared in the type of soil.
  
  KEY WORDS: saturated hydraulic conductivity, grain curve, soil type, laboratory method, empirical method according to Špaček
  
  Address:
  - Michaela Danáčová, Katedra vodného hospodárstva krajiny, Stavebná fakulta, STU v Bratislave, Radlinského 11, 810 05 Bratislava (Corresponding author. Tel.:+ 4212 59 274 627 Fax.: Email: michaela.danacova@stuba.sk)
  - Radovan Nosko, Katedra vodného hospodárstva krajiny, Stavebná fakulta, STU v Bratislave, Radlinského 11, 810 05 Bratislava
  - Marcela Maliariková, Katedra vodného hospodárstva krajiny, Stavebná fakulta, STU v Bratislave, Radlinského 11, 810 05 Bratislava
  - Miroslav Kandera, Katedra vodného hospodárstva krajiny, Stavebná fakulta, STU v Bratislave, Radlinského 11, 810 05 Bratislava
  - Roman Výleta, Katedra vodného hospodárstva krajiny, Stavebná fakulta, STU v Bratislave, Radlinského 11, 810 05 Bratislava

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 89 - 93, doi: 10.31577/ahs-2019-0020.01.0010
Scientific Paper, English

Márton Jolánkai, Katalin M. Kassai, Ákos Tarnawa: Water footprint of field crop species based on their protein yield

 Full Text in PDF     47 DOWNLOADS

• Water availability is one of the major physiological factors influencing plant growth and development. An assessment study has been done at the Szent István University, Gödöllő to evaluate and identify the water footprint of protein yield of field crop species. Six field crop species (Sugar beet Beta vulgaris, winter barley Hordeum vulgare, winter wheat Triticum aestivum, maize Zea mays, potato Solanum tuberosum, and alfalfa Medicago sativa) were involved in the study. Evapotranspiration patterns of the crops studied have been identified and physiologically reliable protein ranges within crop yields were evaluated. The results obtained suggest, that water footprint of cereals proved to be the lowest, however maize values were highly affected by the high variability of protein yield. Alfalfa, potato and sugar beet water footprints were in accordance with their evapotranspiration patterns
  
  KEY WORDS: water footprint, evapotranspiration, protein, field crop species
  
  Address:
  - Márton Jolánkai, Szent István University, Crop Production Institute, 2100 Gödöllő, Páter Károly u. 1.Katalin M. (Corresponding author. Tel.:+36-204174363 Fax.: Email: jolankai.marton@mkk.szie.hu)
  - Katalin M. Kassai, Szent István University, Crop Production Institute, 2100 Gödöllő, Páter Károly u. 1.
  - Ákos Tarnawa, Szent István University, Crop Production Institute, 2100 Gödöllő, Páter Károly u. 1.

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 94 - 101, doi: 10.31577/ahs-2019-0020.01.0011
Scientific Paper, Slovak

David Honek, Zuzana Németová, Silvia Kohnová: Modelling of sediment delivery amounts by a physically based erosion-3D model and empirical model USPED in the Svacenicky creek catchment

 Full Text in PDF     62 DOWNLOADS

• The aim of the paper is to quantify the amount of sediments using a physically based Erosion-3D model and empirical model USPED in the Svacenicky creek catchment. The analysis was carried out for the period from IX.2015 to XI.2016 with input data based on real measured rainfall events that have been determined as erosion effective within the selected period. The amount of sediments quantified by the physically based model and empirical model were compared with the measured data obtained by the bathymetry of the bottom in Svacenicky polder, which is located in the Svacenicky creek catchment. Based on the results it can be concluded that the physically based model represents more appropriate and accurate approach for determining the amount of eroded material in the catchment then an empirical one
  
  KEY WORDS: physically based model, modelling of erosion processes, empirical modelling, water erosion, amount of sediments, extreme rainfall event
  
  Address:
  - David Honek, Geografický ústav, Přírodovědecká fakulta, Masarykova Univerzita, Kotlářská 2, 611 37, Brno, Výzkumný ústav vodohospodářský T.G.M, Podbabská 2582/30, 160 00, Praha 6 (Corresponding author. Tel.:+420 541 126 317 Fax.: Email: ston.david@windowslive.com)
  - Zuzana Németová, Katedra vodného hospodárstva krajiny, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava
  - Silvia Kohnová, Katedra vodného hospodárstva krajiny, Stavebná fakulta, Slovenská technická univerzita v Bratislave, Radlinského 11, 810 05 Bratislava

Acta Hydrologica Slovaca, Vol. 20, No. 1, 2019, p. 102 - 110, doi: 10.31577/ahs-2019-0020.01.0012
Scientific Paper, Slovak

Viera Kováčová: Level of surface water eutrophication in Danube river basin

 Full Text in PDF     61 DOWNLOADS

• Eutrophication as excessive plant growth resulting from nutrient enrichment (mainly nitrogen and phosphorus compounds) by human activity is the primary problem relating most surface waters today. The external supplies of N and P to aquatic ecosystems are derived from a wide variety of sources, including groundwater, fluvial, and atmospheric inputs. The environmental consequences of excessive nutrient enrichment are the degradation of water resources by eutrophication and worsening of water quality. Monitoring of surface water bodies has been provided in terms of requirements of the Water Framework Directive in the period of 2010–2015. With regards of international legislative for the ecological status assessment, chemical status, biological quality elements, supporting physical-chemical and hydro-morphological quality elements have been investigated. The aim of this contribution was to evaluate eutrophication state of water in Danube River basin following the assessment physical-chemical and microbiological indicators in monitored period. Nitrate-N concentrations 1 of 16 monitoring sites (6.66 %) in 2015 was over the limit value 5 mg.l-1 N-NO3-. Nitrite-N concentrations 15 of 17 monitoring sites (88.23%) in 2010 and 4 of 16 (25%) in 2015 was over the limit value 0.02 mg.l-1 N-NO2-. For phosphorus, of 17 monitoring sites 1 (5.88%) was over the limit value 0.4 mg.l-1 Ptot in 2010, all of the samples meet the criteria in 2015 and are not at risk. In general, the rate of increase the external supplies of N and P has slowed down in Danube River basin during the monitoring period.
  
  KEY WORDS: eutrophication, nitrogen, phosphorus, nutrients, point and non-point sources of pollution
  
  Address:
  - Viera Kováčová, Ústav hydrológie SAV, Dúbravská cesta 9, 841 04 Bratislava (Corresponding author. Tel.:+ 421 2 32 293 510 Fax.: Email: kovacova@uh.savba.sk)