J. Hydrol. Hydromech., Vol. 62, No. 3, 2014, p. 169 - 176, doi: [DOIHTML]
Scientific Paper, English

Miriam Fendeková, Pavla Pekárová, Marián Fendek, Ján Pekár, Peter Škoda: Global drivers effect in multi-annual variability of runoff

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• Changes in runoff parameters are very important for Slovakia, where stream-flow discharges, being supplied by precipitation and groundwater runoff, are preferentially influenced by climatic conditions. Therefore, teleconnections between runoff parameters, climate parameters and global atmospheric drivers such as North Atlantic Oscillation, Southern Pacific Oscillation, Quasi-biennial oscillation and solar activity were studied in the Nitra River Basin, Slovakia. Research was mostly based on records of 80 years (1931–2010) for discharges and baseflow, and 34 years for groundwater heads. Methods of autocorrelation, spectral analysis, cross-correlation and coherence function were used. Results of auto-correllograms for discharges, groundwater heads and base flow values showed a very distinct 11-year and 21-year periodicity. Spectrogram analysis documented the 11-year, 7.8-year, 3.6-year and 2.4-year periods in the discharge, precipitation and air temperature time series. The same cycles except of 11-years were also identified in the long-term series of the North Atlantic Oscillation and Southern Pacific Oscillation indices. The cycle from approximately 2.3 to 2.4-years is most likely connected with Quasi-biennial oscillation. The close negative correlation between the North Atlantic Oscillation winter index and the hydrological surface and groundwater parameters can be used for their prediction within the same year and also for one year in advance.
  
  KEY WORDS: Runoff variability; Global climatic drivers; Inter-relationships; Nitra River Basin; Slovakia.
  
  Address:
  - Miriam Fendeková, Department of Hydrogeology, Faculty of Natural Sciences of Comenius University in Bratislava, Pav. G, Mlynska dolina, 842 15 Bratislava 4, Slovakia. (Corresponding author. Tel.: Fax.: Email: fendekova@fns.uniba.sk)
  - Pavla Pekárová, Institute of Hydrology, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3, Slovakia.
  - Marián Fendek, Department of Hydrogeology, Faculty of Natural Sciences of Comenius University in Bratislava, Pav. G, Mlynska dolina, 842 15 Bratislava 4, Slovakia.
  - Ján Pekár, Department of Applied Mathematics and Statistics, Faculty of Mathematics, Physics and Informatics, Comenius University, 842 48 Bratislava, Slovakia.
  - Peter Škoda, Slovak Hydrometeorological Institute, Jeseniova 17, 833 15 Bratislava, Slovakia.

J. Hydrol. Hydromech., Vol. 63, No. 3, 2015, p. 201 - 209, doi: [DOIHTML]
Scientific Paper, English

Luca Brocca, Christian Massari, Luca Ciabatta, Tommaso Moramarco, Daniele Penna, Giulia Zuecco, Luisa Pianezzola, Marco Borga, Patrick Matgen, José Martínez-Fernández: Rainfall estimation from in situ soil moisture observations at several sites in Europe: an evaluation of the SM2RAIN algorithm

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• Rain gauges, weather radars, satellite sensors and modelled data from weather centres are used operationally for estimating the spatial-temporal variability of rainfall. However, the associated uncertainties can be very high, especially in poorly equipped regions of the world. Very recently, an innovative method, named SM2RAIN, that uses soil moisture observations to infer rainfall, has been proposed by Brocca et al. (2013) with very promising results when applied with in situ and satellite-derived data. However, a thorough analysis of the physical consistency of the SM2RAIN algorithm has not been carried out yet. In this study, synthetic soil moisture data generated from a physically-based soil water balance model are employed to check the reliability of the assumptions made in the SM2RAIN algorithm. Next, high quality and multiyear in situ soil moisture observations, at different depths (5–30 cm), and rainfall for ten sites across Europe are used for testing the performance of the algorithm, its limitations and applicability range. SM2RAIN shows very high accuracy in the synthetic experiments with a correlation coefficient, R, between synthetically generated and simulated data, at daily time step, higher than 0.940 and an average Bias lower than 4%. When real datasets are used, the agreement between observed and simulated daily rainfall is slightly lower with average R-values equal to 0.87 and 0.85 in the calibration and validation periods, respectively. Overall, the performance is found to be better in humid temperate climates and for sensors installed vertically. Interestingly, algorithms of different complexity in the reproduction of the underlying hydrological processes provide similar results. The average contribution of surface runoff and evapotranspiration components amounts to less than 4% of the total rainfall, while the soil moisture variations (63%) and subsurface drainage (30%) terms provide a much higher contribution. Overall, the SM2RAIN algorithm is found to perform well both in the synthetic and real data experiments, thus offering a new and independent source of data for improving rainfall estimation, and consequently enhancing hydrological, meteorological and climatic studies.
  
  KEY WORDS: Rainfall; Soil moisture; In situ observations; Experimental sites; SM2RAIN.
  
  Address:
  - Luca Brocca, Research Institute for Geo-Hydrological Protection, National Research Council, Perugia, Via Madonna Alta 126, 06128 Perugia, Italy. (Corresponding author. Tel.:+39 0755014418 Fax.: +39 0755014420 Email: luca.brocca@irpi.cnr.it)
  - Christian Massari, Research Institute for Geo-Hydrological Protection, National Research Council, Perugia, Via Madonna Alta 126, 06128 Perugia, Italy.
  - Luca Ciabatta, Research Institute for Geo-Hydrological Protection, National Research Council, Perugia, Via Madonna Alta 126, 06128 Perugia, Italy.
  - Tommaso Moramarco, Research Institute for Geo-Hydrological Protection, National Research Council, Perugia, Via Madonna Alta 126, 06128 Perugia, Italy.
  - Daniele Penna, Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza dell'Universita 5, Bolzano, Italy.
  - Giulia Zuecco, Department of Land and Agroforest Environments, University of Padova, Via dell'Universita 16, Legnaro, Italy.
  - Luisa Pianezzola, Department of Land and Agroforest Environments, University of Padova, Via dell'Universita 16, Legnaro, Italy.
  - Marco Borga, Department of Land and Agroforest Environments, University of Padova, Via dell'Universita 16, Legnaro, Italy.
  - Patrick Matgen, Luxembourg Institute of Science and Technology (LIST), ERIN, Avenue Des Hauts-Fourneaux 5, Esch-Sur-Alzette, Luxembourg.
  - José Martínez-Fernández, Centro Hispano Luso de Investigaciones Agrarias, USAL, Calle del Duero 12, Villamayor, Spain.

J. Hydrol. Hydromech., Vol. 63, No. 1, 2015, p. 1 - 12, doi: [DOIHTML]
Scientific Paper, English

Sape A. Miedema: A head loss model for homogeneous slurry transport for medium sized particles

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• Slurry transport in horizontal and vertical pipelines is one of the major means of transport of sands and gravels in the dredging industry. There exist 4 main flow regimes, the fixed or stationary bed regime, the sliding bed regime, the heterogeneous flow regime and the homogeneous flow regime. Of course the transitions between the regimes are not very sharp, depending on parameters like the particle size distribution. The focus in this paper is on the homogeneous regime. Often the so called equivalent liquid model (ELM) is applied, however many researchers found hydraulic gradients smaller than predicted with the ELM, but larger that the hydraulic gradient of liquid. Talmon (2011, 2013) derived a fundamental equation (method) proving that the hydraulic gradient can be smaller than predicted by the ELM, based on the assumption of a particle free viscous sub-layer. He used a 2D velocity distribution without a concentration distribution. In this paper 5 methods are described (and derived) to determine the hydraulic gradient in homogeneous flow, of which the last method is based on pipe flow with a concentration distribution. It appears that the use of von Driest (Schlichting, 1968) damping, if present, dominates the results, however applying a concentration distribution may neutralise this. The final equation contains both the damping and a concentration distribution giving the possibility to calibrate the constant in the equation with experimental data. The final equation is flexible and gives a good match with experimental results in vertical and horizontal pipelines for a value of ACv = 1.3. Data of horizontal experiments Dp = 0.05 – 0.30 m, d = 0.04 mm, vertical experiments Dp = 0.026 m, d = 0.125, 0.345, 0.560, and 0.750 mm.
  
  KEY WORDS: Slurry transport; Homogeneous transport; Viscous sub layer; Mixing length.
  
  Address:
  - Sape A. Miedema, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands. (Corresponding author. Tel.:+31-15-2788359 Fax.: Email: s.a.miedema@tudelft.nl)

J. Hydrol. Hydromech., Vol. 62, No. 3, 2014, p. 241 - 247, doi: [DOIHTML]
Scientific Paper, English

Pavel Vlasák, Zdeněk Chára, Jan Krupička, Jiří Konfršt: Experimental investigation of coarse particles-water mixture flow in horizontal and inclined pipes

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• The effect of solid concentration and mixture velocity on the flow behaviour, pressure drops, and concentration distribution of coarse particle–water mixtures in horizontal, vertical, and inclined smooth stainless steel pipes of inner diameter D = 100 mm was experimentally investigated. Graded basalt pebbles were used as solid particles. The study revealed that the coarse-grained particle-water mixtures in the horizontal and inclined pipes were significantly stratified. The solid particles moved principally in a layer close to the pipe invert; however for higher and moderate flow velocities, particle saltation became the dominant mode of particle conveyance. Frictional pressure drops in the horizontal pipe were found to be markedly higher than in the vertical pipe, while the frictional pressure drops in the ascending pipe increased with inclination angle up to about 30°.
  
  KEY WORDS: Hydraulic pipelining; Coarse-grained slurry; Pressure drops; Pipe inclination; Concentration distribution.
  
  Address:
  - Pavel Vlasák, Institute of Hydrodynamics of the Academy of Sciences of the Czech Republic, v. v. i., Pod Paťankou 30/5, 166 12 Prague 6, Czech Republic. (Corresponding author. Tel.: Fax.: Email: vlasak@ih.cas.cz)
  - Zdeněk Chára, Institute of Hydrodynamics of the Academy of Sciences of the Czech Republic, v. v. i., Pod Paťankou 30/5, 166 12 Prague 6, Czech Republic.
  - Jan Krupička, Institute of Hydrodynamics of the Academy of Sciences of the Czech Republic, v. v. i., Pod Paťankou 30/5, 166 12 Prague 6, Czech Republic.
  - Jiří Konfršt, Institute of Hydrodynamics of the Academy of Sciences of the Czech Republic, v. v. i., Pod Paťankou 30/5, 166 12 Prague 6, Czech Republic.

J. Hydrol. Hydromech., Vol. 67, No. 1, 2019, p. 70 - 81, doi: [DOIHTML]
Scientific Paper, English

Philippe Riboust, Guillaume Thirel, Nicolas Le Moine, Pierre Ribstein: Revisiting a simple degree-day model for integrating satellite data: implementation of SWE-SCA hystereses

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• Conceptual degree-day snow models are often calibrated using runoff observations. This makes the snow models dependent on the rainfall-runoff model they are coupled with. Numerous studies have shown that using Snow Cover Area (SCA) remote sensing observation from MODIS satellites helps to better constrain parameters. The objective of this study was to calibrate the CemaNeige degree-day snow model with SCA and runoff observations. In order to calibrate the snow model with SCA observations, the original CemaNeige SCA formulation was revisited to take into account the hysteresis that exists between SCA and the snow water equivalent (SWE) during the accumulation and melt phases. Several parametrizations of the hysteresis between SWE and SCA were taken from land surface model literature. We showed that they improve the performances of SCA simulation without degrading the river runoff simulation. With this improvement, a new calibration method of the snow model was developed using jointly SCA and runoff observations. Further analysis showed that the CemaNeige calibrated parameter sets are more robust for simulating independent periods than parameter sets obtained from discharge calibration only. Calibrating the snow model using only SCA data gave mixed results, with similar performances as using median parameters from all watersheds calibration.
  
  KEY WORDS: Snow model; Hysteresis parametrization; MODIS snow cover area; Rainfall-runoff model.
  
  Address:
  - Philippe Riboust, Sorbonne Universités, UPMC Univ., Paris 06, CNRS, EPHE, UMR 7619 Metis, 4 place Jussieu, 75005 Paris, France. Hydrosystems and Bioprocesses Research Unit (HBAN), Irstea, 1 rue Pierre-Gilles de Gennes, CS 10030, 92761 Antony Cedex, France. (Corresponding author. Tel.: Fax.: Email: philippe.riboust@irstea.fr)
  - Guillaume Thirel, Hydrosystems and Bioprocesses Research Unit (HBAN), Irstea, 1 rue Pierre-Gilles de Gennes, CS 10030, 92761 Antony Cedex, France.
  - Nicolas Le Moine, Sorbonne Universités, UPMC Univ., Paris 06, CNRS, EPHE, UMR 7619 Metis, 4 place Jussieu, 75005 Paris, France.
  - Pierre Ribstein, Sorbonne Universités, UPMC Univ., Paris 06, CNRS, EPHE, UMR 7619 Metis, 4 place Jussieu, 75005 Paris, France.

J. Hydrol. Hydromech., Vol. 62, No. 3, 2014, p. 186 - 196, doi: [DOIHTML]
Scientific Paper, English

Veronika Bačová Mitková, Dana Halmová: Joint modeling of flood peak discharges, volume and duration: a case study of the Danube River in Bratislava

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• The study is focused on the analysis and statistical evaluation of the joint probability of the occurrence of hy-drological variables such as peak discharge (Q), volume (V) and duration (t). In our case study, we focus on the bivariate statistical analysis of these hydrological variables of the Danube River in Bratislava gauging station, during the period of 1876–2013. The study presents the methodology of the bivariate statistical analysis, choice of appropriate marginal distributions and appropriate copula functions in representing the joint distribution. Finally, the joint return periods and conditional return periods for some hydrological pairs (Q-V, V-t, Q-t) were calculated. The approach using copulas can reproduce a wide range of correlation (nonlinear) frequently observed in hydrology. Results of this study provide comprehensive information about flood where a devastating effect may be increased in the case where its three basic components (or at least two of them) Q, V and t have the same significance.
  
  KEY WORDS: The Danube River; Joint distribution; Copula functions; Peak flow; Volume and duration of the wave; Multivariate frequency analysis.
  
  Address:
  - Veronika Bačová Mitková, Institute of Hydrology SAS, Račianska 75, 831 02 Bratislava, Slovakia. (Corresponding author. Tel.:+421249268242 Fax.: +421244259311 Email: mitkova@uh.savba.sk)
  - Dana Halmová, Institute of Hydrology SAS, Račianska 75, 831 02 Bratislava, Slovakia.

J. Hydrol. Hydromech., Vol. 63, No. 1, 2015, p. 29 - 37, doi: [DOIHTML]
Scientific Paper, English

Igor Ljubenkov: Hydrodynamic modeling of stratified estuary: case study of the Jadro River (Croatia)

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• The Jadro River with total length of 4.3 km and average annual discharge of 7.9 m3 s–1 is a relatively small river on the east coast of the Adriatic Sea, close to Split. Field campaign measurements were made to estimate salt intrusion in the Jadro estuary in July 2012. This measurement confirmed the stratified character of the estuary where fresh water flows in a thin layer over denser sea water. Furthermore, a numerical model was set up for simulating unsteady stratified flow without mixing between the layers. The model is applied for the Jadro River and field measurements are used for calibration. In addition, the steady state of stratification within the estuary is analyzed by a box model which assumes mixing between layers. Results of the numerical and the box models were compared. The flushing time estimated with the box model is approximately 1.5 day for summer steady conditions. Numerical analysis however shows that the residence time is much larger owing to flow unsteadiness.
  
  KEY WORDS: Estuary; Salinity; Numerical model; Box model; Jadro; Croatia.
  
  Address:
  - Igor Ljubenkov, Water Development Ltd., Kvaternikova 7, 21000 Split, Croatia. (Corresponding author. Tel.: Fax.: Email: iljubenkov@gmail.com)

J. Hydrol. Hydromech., Vol. 63, No. 1, 2015, p. 71 - 81, doi: [DOIHTML]
Scientific Paper, English

Hana Hlaváčiková, Viliam Novák, Ladislav Holko: On the role of rock fragments and initial soil water content in the potential subsurface runoff formation

 Full Text in PDF     234 DOWNLOADS

• Stony soils are composed of fractions (rock fragments and fine soil) with different hydrophysical characteristics. Although they are abundant in many catchments, their properties are still not well understood. This article presents basic characteristics (texture, stoniness, saturated hydraulic conductivity, and soil water retention) of stony soils from a mountain catchment located in the highest part of the Carpathian Mountains and summarizes results of water flow modeling through a hypothetical stony soil profile. Numerical simulations indicate the highest vertical outflow from the bottom of the profile in soils without rock fragments under ponding infiltration condition. Simulation of a more realistic case in a mountain catchment, i.e. infiltration of intensive rainfall, shows that when rainfall intensity is lower than the saturated hydraulic conductivity of the stony soil, the highest outflow is predicted in a soil with the highest stoniness and high initial water content of soil matrix. Relatively low available retention capacity in a stony soil profile and consequently higher unsaturated hydraulic conductivity leads to faster movement of the infiltration front during rainfall.
  
  KEY WORDS: Stony soils; Infiltration; Stoniness; Initial soil water content; Mathematical modeling.
  
  Address:
  - Hana Hlaváčiková, Institute of Hydrology, Slovak Academy of Sciences, Račianska 75, 83102 Bratislava, Slovakia. (Corresponding author. Tel.: Fax.: Email: hlavacikova@uh.savba.sk)
  - Viliam Novák, Institute of Hydrology, Slovak Academy of Sciences, Račianska 75, 83102 Bratislava, Slovakia.
  - Ladislav Holko, Institute of Hydrology, Slovak Academy of Sciences, Račianska 75, 83102 Bratislava, Slovakia.

J. Hydrol. Hydromech., Vol. 67, No. 2, 2019, p. 179 - 190, doi: [DOIHTML]
Scientific Paper, English

Fatemeh Afrasiabi, Habib Khodaverdiloo, Farrokh Asadzadeh, Martinus Th. van Genuchten: Comparison of alternative soil particle-size distribution models and their correlation with soil physical attributes

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• Complete descriptions of the particle-size distribution (PSD) curve should provide more information about various soil properties as opposed to only the textural composition (sand, silt and clay (SSC) fractions). We evaluated the performance of 19 models describing PSD data of soils using a range of efficiency criteria. While different criteria produced different rankings of the models, six of the 19 models consistently performed the best. Mean errors of the six models were found to depend on the particle diameter, with larger error percentages occurring in the smaller size range. Neither SSC nor the geometric mean diameter and its standard deviation correlated significantly with the saturated hydraulic conductivity (Kfs); however, the parameters of several PSD models showed significant correlation with Kfs. Porosity, mean weight diameter of the aggregates, and bulk density also showed significant correlations with PSD model parameters. Results of this study are promising for developing more accurate pedotransfer functions.
  
  KEY WORDS: Lake Urmia (Iran); Particle-size distribution models; Pedotransfer functions; Soil physical properties.
  
  Address:
  - Fatemeh Afrasiabi, Department of Soil Science, Urmia University, Urmia 57135-165, Iran.
  - Habib Khodaverdiloo, Department of Soil Science, Urmia University, Urmia 57135-165, Iran. (Corresponding author. Tel.: Fax.: Email: h.khodaverdiloo@urmia.ac.ir)
  - Farrokh Asadzadeh, Department of Soil Science, Urmia University, Urmia 57135-165, Iran.
  - Martinus Th. van Genuchten, Department of Earth Sciences, Utrecht University, Utrecht, Netherlands. Center for Environmental Studies, CEA, Sao Paulo State University, UNESP, Rio Claro, SP, Brazil.

J. Hydrol. Hydromech., Vol. 67, No. 1, 2019, p. 1 - 3, doi: [DOIHTML]
Information, English

Massimiliano Zappa, Ladislav Holko, Martin Šanda, Tomáš Vitvar, Juraj Parajka: Thematic Issue on Snow Resources and Hydrological Cycle

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• Data not available
  
  KEY WORDS: Data not available
  
  Address:
  - Massimiliano Zappa, Swiss Federal Research Institute WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland. (Corresponding author. Tel.: Fax.: Email: massimiliano.zappa@wsl.ch)
  - Ladislav Holko, Slovak Academy of Sciences, Institute of Hydrology, Dúbravská cesta 9, 84104 Bratislava, Slovakia.
  - Martin Šanda, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic.
  - Tomáš Vitvar, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic. Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador.
  - Juraj Parajka, Institute of Hydraulic Engineering and Water Resources Management, Vienna University of Technology, Vienna, Austria.