J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 105 - 113, doi: 10.1515/johh-2017-0008
Scientific Paper, English

Jindřich Dolanský, Zdeněk Chára, Pavel Vlasák, Bohuš Kysela: Lattice Boltzmann method used to simulate particle motion in a conduit

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• A three-dimensional numerical simulation of particle motion in a pipe with a rough bed is presented. The simulation based on the Lattice Boltzmann Method (LBM) employs the hybrid diffuse bounce-back approach to model moving boundaries. The bed of the pipe is formed by stationary spherical particles of the same size as the moving particles. Particle movements are induced by gravitational and hydrodynamic forces. To evaluate the hydrodynamic forces, the Momentum Exchange Algorithm is used. The LBM unified computational frame makes it possible to simulate both the particle motion and the fluid flow and to study mutual interactions of the carrier liquid flow and particles and the particle–bed and particle–particle collisions. The trajectories of simulated and experimental particles are compared. The Particle Tracking method is used to track particle motion. The correctness of the applied approach is assessed.
  
  KEY WORDS: Lattice Boltzmann method; Particle motion; Particle–fluid interaction; PIV; Particle tracking.
  
  Address:
  - Jindřich Dolanský, Institute of Hydrodynamics of the Czech Academy of Sciences, v. v. i., Pod Paťankou 30/5, 166 12 Prague 6, Czech Republic. (Corresponding author. Tel.: Fax.: Email: dolansky@ih.cas.cz)
  - Zdeněk Chára, Institute of Hydrodynamics of the Czech Academy of Sciences, v. v. i., Pod Paťankou 30/5, 166 12 Prague 6, Czech Republic.
  - Pavel Vlasák, Institute of Hydrodynamics of the Czech Academy of Sciences, v. v. i., Pod Paťankou 30/5, 166 12 Prague 6, Czech Republic.
  - Bohuš Kysela, Institute of Hydrodynamics of the Czech Academy of Sciences, v. v. i., Pod Paťankou 30/5, 166 12 Prague 6, Czech Republic.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 114 - 122, doi: 10.1515/johh-2017-0002
Scientific Paper, English

Jana Votrubova, Michal Dohnal, Tomas Vogel, Martin Sanda, Miroslav Tesar: Episodic runoff generation at Central European headwater catchments studied using water isotope concentration signals

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• Hydrological monitoring in small headwater catchments provides the basis for examining complex interrelating hydraulic processes that govern the runoff generation. Contributions of different subsurface runoff mechanisms to the catchment discharge formation at two small forested headwater catchments are studied with the help of their natural isotopic signatures. The Uhlirska catchment (Jizera Mts., Czech Republic) is situated in headwater area of the Lusatian Neisse River. The catchment includes wetlands at the valley bottom developed over deluviofluvial granitic sediments surrounded by gentle hillslopes with shallow soils underlain by weathered granite. The Liz catchment (Bohemian Forest, Czech Republic) is situated in headwater area of the Otava River. It belongs to hillslope-type catchments with narrow riparian zones. The soil at Liz is developed on biotite paragneiss bedrock. The basic comparison of hydrological time series reveals that the event-related stream discharge variations at the Uhlirska catchment are bigger and significantly more frequent than at Liz. The analysis of isotope concentration data revealed different behavior of the two catchments during the major rainfall-runoff events. At Uhlirska, the percentage of the direct runoff formed by the event water reaches its maximum on the falling limb of the hydrograph. At Liz, the event water related fraction of the direct outflow is maximal on the rising limb of the hydrograph and then lowers. The hydraulic functioning of the Uhlirska catchment is determined by communication between hillslope and riparian zone compartments.
  
  KEY WORDS: 18O isotope; Headwater catchment runoff; Subsurface runoff; Tracer; Rainfall-runoff episodes.
  
  Address:
  - Jana Votrubova, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic. (Corresponding author. Tel.:+420 22435 4355 Fax.: Email: jana.votrubova@fsv.cvut.cz)
  - Michal Dohnal, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic.
  - Tomas Vogel, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic.
  - Martin Sanda, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic.
  - Miroslav Tesar, Institute of Hydrodynamics of the Czech Academy of Sciences, Pod Paťankou 5, Prague 6, Czech Republic.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 123 - 133, doi: 10.1515/johh-2017-0011
Scientific Paper, English

Yongwei Liu, Wen Wang, Yiming Hu: Investigating the impact of surface soil moisture assimilation on state and parameter estimation in SWAT model based on the ensemble Kalman filter in upper Huai River basin

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• This paper investigates the impact of surface soil moisture assimilation on the estimation of both parameters and states in the Soil and Water Assessment Tool (SWAT) model using the ensemble Kalman filter (EnKF) method in upper Huai River basin. The investigation is carried out through a series of synthetic experiments and real world tests using a merged soil moisture product (ESA CCI SM) developed by the European Space Agency, and considers both the joint state-parameter updating and only state updating schemes. The synthetic experiments show that with joint stateparameter update, the estimation of model parameter SOL_AWC (the available soil water capacity) and model states (the soil moisture in different depths) can be significantly improved by assimilating the surface soil moisture. Meanwhile, the runoff modeling for the whole catchment is also improved. With only state update, the improvement on runoff modeling shows less significance and robustness. Consistent with the synthetic experiments, the assimilation of the ESA CCI SM with joint state-parameter update shows considerable capability in the estimation of SOL_AWC. Both the joint stateparameter update and the only state update scheme could improve the streamflow modeling although the optimal model and observation error parameters for them are quite different. However, due to the high vegetation coverage of the study basin, and the strong spatial mismatch between the satellite and the model simulated soil moisture, it is still challenging to significantly benefit the runoff estimates by assimilating the ESA CCI SM.
  
  KEY WORDS: Soil moisture; EnKF; SWAT; ESA CCI SM.
  
  Address:
  - Yongwei Liu, College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China.
  - Wen Wang, College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China. (Corresponding author. Tel.: Fax.: Email: w.wang@126.com)
  - Yiming Hu, College of Hydrology and Water Resources, Hohai University, Nanjing 210098, China.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 134 - 145, doi: 10.1515/johh-2017-0007
Scientific Paper, English

Alireza Sadeghi-Pouya, Jafar Nouri, Nabiollah Mansouri, Ali Kia-Lashaki: Developing an index model for flood risk assessment in the western coastal region of Mazandaran, Iran

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• This paper represents an index model developed for the assessment of risk caused by river floods. The main purpose of this model is to evaluate the flood risk in the western coastal region of Mazandaran Province/Iran. The model assesses the risk at triple components, i.e. the flood occurrence probability, vulnerability and consequences, through identification and evaluation of effective criteria categorized into seven indexes (environmental, technical, economic, social, depth, population and sensitivity ones) that are involved in all stages of flooding (source, pathway and receptor). The flood risk in the developed model is defined by a dimensionless magnitude called as risk score between 0 and 100 for each zone of the area under assessment by calculating and combining of two newly defined factors: occurrence and vulnerability factor and impact factor. The model was applied in a case study, the Nowshahr flood in 2012. The results showed that: (i) the flood risk zoning was compared with observed data for aspect of the damages, and general agreement between them was obtained; (ii) for urban zones, which surrounded by two rivers, would easily be in critical condition and rescue operations face difficulties; and (iii) it is necessary to review the location of the emergency services, according the flood risk zoning.
  
  KEY WORDS: Flood risk; Index model; Source-pathway-receptor; Mazandaran.
  
  Address:
  - Alireza Sadeghi-Pouya, Department of Environmental Management, Science and Research Branch, Islamic Azad University, Tehran, Iran.
  - Jafar Nouri, Department of Environmental Management, Science and Research Branch, Islamic Azad University, Tehran, Iran. (Corresponding author. Tel.:+9811-52351741 Fax.: Email: nourijafar@srbiau.ac.ir; nourijafar@gmail.com)
  - Nabiollah Mansouri, Department of Environmental Management, Science and Research Branch, Islamic Azad University, Tehran, Iran.
  - Ali Kia-Lashaki, Department of Forestry, Nowshahr Branch, Islamic Azad University, Nowshahr, Iran.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 146 - 153, doi: 10.1515/johh-2017-0005
Scientific Paper, English

Mariusz Ptak, Dariusz Wrzesiński, Adam Choiński: Long-term changes in the hyrological regime of high mountain Lake Morskie Oko (Tatra Mountains, Central Europe)

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• The paper discusses changes in the hydrological regime of high mountain Lake Morskie Oko located in the Tatra Mountains, in the Tatra Mountains National Park, a UNESCO biosphere reserve (MaB). According to the research conducted in the years 1971–2015, its water stages decreased by 3.5 cm·dec–1, mean annual water temperature increased by 0.3ºC·dec–1 and the duration of ice phenomena and ice cover was reduced by 10 day·dec–1. No considerable changes in maximum values of ice cover thickness were recorded. Such tendencies are primarily caused by long-term changes in climatic conditions – air temperature and atmospheric precipitation. The hydrological regime of the lake was also determined by changes in land use in the lake’s catchment and its location in high mountains.
  
  KEY WORDS: Water temperature; Ice phenology; Water level; Climate change; Tatra Mountains.
  
  Address:
  - Mariusz Ptak, Institute of Physical Geography and Environmental Planning, Adam Mickiewicz University, Dzięgielowa 27, 61 680 Poznań, Poland. (Corresponding author. Tel.: Fax.: Email: marp114@wp.pl)
  - Dariusz Wrzesiński, Institute of Physical Geography and Environmental Planning, Adam Mickiewicz University, Dzięgielowa 27, 61 680 Poznań, Poland.
  - Adam Choiński, Institute of Physical Geography and Environmental Planning, Adam Mickiewicz University, Dzięgielowa 27, 61 680 Poznań, Poland.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 154 - 164, doi: 10.1515/johh-2017-0003
Scientific Paper, English

Martin Šanda, Pavlína Sedlmaierová, Tomáš Vitvar, Christina Seidler, Matthias Kändler, Jakub Jankovec, Alena Kulasová, František Paška: Pre-event water contributions and streamwater residence times in different land use settings of the transboundary mesoscale Lužická Nisa catchment

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• The objective of the study was to evaluate the spatial distribution of peakflow pre-event water contributions and streamwater residence times with emphasis on land use patterns in 38 subcatchments within the 687 km2 large mesoscale transboundary catchment Lužická Nisa. Mean residence times between 8 and 27 months and portions of pre-event water between 10 and 97% on a storm event peakflow were determined, using 18O data in precipitation and streamwater from a weekly monitoring of nearly two years. Only a small tracer variation buffering effect of the lowland tributaries on the main stem was observed, indicating the dominant impact on the mountainous headwaters on the runoff generation. Longest mean streamwater residence times of 27 months were identified in the nearly natural headwaters of the Jizera Mountains, revealing no ambiguous correlation between the catchment area and altitude and the mean resi-dence time of streamwater. Land use control on the pre-event water portions were determined for three land use catego-ries with percentage of urban areas from 0 to 10%, 10 to 20% and more than 20%. The fraction of pre-event water in the first category decreases from 97% to 65% with the increasing percentage of forest from 76% to 100%, revealing that for-ests may provide only a limited infiltration of precipitation due to leaf interception and soil water use for transpiration. Fractions of pre-event water of 39–87% in the second (agricultural catchments) and of 10–35% in the third (urbanized catchments) category increase with percentage of non-urban areas.
  
  KEY WORDS: 18O isotope; Stormflow event; Peak pre-event contributions; Mean residence time; Land use.
  
  Address:
  - Martin Šanda, Department of Irrigation, Drainage and Landscape Engineering, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic. (Corresponding author. Tel.:+420 22435 3739 Fax.: +420 233324861 Email: martin.sanda@fsv.cvut.cz)
  - Pavlína Sedlmaierová, Department of Irrigation, Drainage and Landscape Engineering, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic.
  - Tomáš Vitvar, Department of Irrigation, Drainage and Landscape Engineering, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic.
  - Christina Seidler, Technische Universität Dresden, International Institute Zittau, Markt 23, 02763 Zittau, Germany.
  - Matthias Kändler, Technische Universität Dresden, International Institute Zittau, Markt 23, 02763 Zittau, Germany.
  - Jakub Jankovec, Department of Irrigation, Drainage and Landscape Engineering, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague 6, Czech Republic.
  - Alena Kulasová, T. G. Masaryk Water Research Institute, Podbabská 30, Prague 6, Czech Republic.
  - František Paška, Crop Research Institute, Drnovská 507, Prague 6, Czech Republic.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 165 - 174, doi: 10.1515/johh-2017-0012
Scientific Paper, English

Milan Stojković, Jasna Plavšić, Stevan Prohaska: Annual and seasonal discharge prediction in the middle Danube River basin based on a modified TIPS (Tendency, Intermittency, Periodicity, Stochasticity) methodology

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• The short-term predictions of annual and seasonal discharge derived by a modified TIPS (Tendency, Intermittency, Periodicity and Stochasticity) methodology are presented in this paper. The TIPS method (Yevjevich, 1984) is modified in such a way that annual time scale is used instead of daily. The reason of extracting a seasonal component from discharge time series represents an attempt to identify the long-term stochastic behaviour. The methodology is applied for modelling annual discharges at six gauging stations in the middle Danube River basin using the observed data in the common period from 1931 to 2012. The model performance measures suggest that the modelled time series are matched reasonably well. The model is then used for the short-time predictions for three annual step ahead (2013–2015). The annual discharge predictions of larger river basins for moderate hydrological conditions show reasonable matching with records expressed as the relative error from –8% to +3%. Irrespective of this, wet and dry periods for the aforementioned river basins show significant departures from annual observations. Also, the smaller river basins display greater deviations up to 26% of the observed annual discharges, whereas the accuracy of annual predictions do not strictly depend on the prevailing hydrological conditions.
  
  KEY WORDS: Stochastic modelling; Annual and seasonal hydrological predictions; TIPS method; The middle Danube River basin.
  
  Address:
  - Milan Stojković, Jaroslav Černi Institute for the Development of Water Resources, Jaroslava Černog 80, 11226 Belgrade, Serbia. (Corresponding author. Tel.: Fax.: Email: milan.stojkovic@jcerni.co.rs)
  - Jasna Plavšić, University of Belgrade, Faculty of Civil Engineering, Bulevar Kralja Aleksandra 73, 11000 Belgrade, Serbia.
  - Stevan Prohaska, Jaroslav Černi Institute for the Development of Water Resources, Jaroslava Černog 80, 11226 Belgrade, Serbia.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 175 - 182, doi: 10.1515/johh-2017-0014
Scientific Paper, English

Stefania Evangelista, Gaspare Giovinco, Selahattin Kocaman: A multi-parameter calibration method for the numerical simulation of morphodynamic problems

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• Calibration of parameters of mathematical models is still a tough task in several engineering problems. Many of the models adopted for the numerical simulations of real phenomena, in fact, are of empirical derivation. Therefore, they include parameters which have to be calibrated in order to correctly reproduce the physical evidence. Thus, the success of a numerical model application depends on the quality of the performed calibration, which can be of great complexity, especially if the number of parameters is higher than one. Calibration is traditionally performed by engineers and researchers through manual trial-and-error procedures. However, since models themselves are increasingly sophisticated, it seems more proper to look at more advanced calibration procedures. In this work, in particular, an optimization technique for a multi-parameter calibration is applied to a two-phase depth-averaged model, already adopted in previous works to simulate morphodynamic processes, such as, for example, the dike erosion by overtopping.
  
  KEY WORDS: Optimization; Calibration; Multi-parameter; Numerical models; Morphodynamic models; Dike erosion.
  
  Address:
  - Stefania Evangelista, Department of Civil and Mechanical Engineering DiCeM, University of Cassino and Southern Lazio, 03043 Cassino, FR, Italy. (Corresponding author. Tel.: Fax.: Email: s.evangelista@unicas.it)
  - Gaspare Giovinco, Department of Civil and Mechanical Engineering DiCeM, University of Cassino and Southern Lazio, 03043 Cassino, FR, Italy.
  - Selahattin Kocaman, Department of Civil Engineering Technical University of Iskenderun 31200 Iskenderun, Hatay, Turkey.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 183 - 191, doi: 10.1515/johh-2017-0001
Scientific Paper, English

Pavel Vlasak, Zdenek Chara, Jiri Konfrst: Flow behaviour and local concentration of coarse particles-water mixture in inclined pipes

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• Narrow particle size distribution basalt pebbles of mean particle size 11.5 mm conveyed by water in the pipe sections of different inclination were investigated on an experimental pipe loop, consisting of smooth stainless steel pipes of inner diameter D = 100 mm. Mixture flow-behaviour and particles motion along the pipe invert were studied in a pipe viewing section, the concentration distribution in pipe cross-section was studied with the application of a gamma-ray densitometer. The study refers to the effect of mixture velocity, overall concentration, and angle of pipe inclination on chord-averaged concentration profiles and local concentration maps, and flow behaviour of the coarse particle-water mixtures. The study revealed that the coarse particle-water mixtures in the inclined pipe sections were significantly stratified, the solid particles moved principally close to the pipe invert, and for higher and moderate flow velocities particle saltation becomes the dominant mode of particle conveying.
  
  KEY WORDS: Coarse particle mixture; Concentration distribution; Effect of pipe inclination; Gamma-ray radiometry; Hydraulic conveying; Mixture flow behaviour.
  
  Address:
  - Pavel Vlasak, Institute of Hydrodynamics of Czech Academy of Sciences, v. v. i., Pod Patankou 30/5, 160 00, Prague 6, Czech Republic. (Corresponding author. Tel.:+420 233109019 Fax.: +420 233324861 Email: vlasak@ih.cas.cz)
  - Zdenek Chara, Institute of Hydrodynamics of Czech Academy of Sciences, v. v. i., Pod Patankou 30/5, 160 00, Prague 6, Czech Republic.
  - Jiri Konfrst, Institute of Hydrodynamics of Czech Academy of Sciences, v. v. i., Pod Patankou 30/5, 160 00, Prague 6, Czech Republic.

J. Hydrol. Hydromech., Vol. 65, No. 2, 2017, p. 192 - 204, doi: 10.1515/johh-2017-0013
Scientific Paper, English

Pintu Das, Sultana Begam, Mritunjay Kumar Singh: Mathematical modeling of groundwater contamination with varying velocity field

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• In this study, analytical models for predicting groundwater contamination in isotropic and homogeneous porous formations are derived. The impact of dispersion and diffusion coefficients is included in the solution of the advection- dispersion equation (ADE), subjected to transient (time-dependent) boundary conditions at the origin. A retardation factor and zero-order production terms are included in the ADE. Analytical solutions are obtained using the Laplace Integral Transform Technique (LITT) and the concept of linear isotherm. For illustration, analytical solutions for linearly space- and time-dependent hydrodynamic dispersion coefficients along with molecular diffusion coefficients are presented. Analytical solutions are explored for the Peclet number. Numerical solutions are obtained by explicit finite difference methods and are compared with analytical solutions. Numerical results are analysed for different types of geological porous formations i.e., aquifer and aquitard. The accuracy of results is evaluated by the root mean square error (RMSE).
  
  KEY WORDS: Solute; Advection; Diffusion; Dispersion; Aquifer; Finite Difference Method.
  
  Address:
  - Pintu Das, Department of Applied Mathematics, Indian Institute of Technology (Indian School of Mines), Dhanbad-826004, Jharkhand, India.
  - Sultana Begam, Department of Applied Mathematics, Indian Institute of Technology (Indian School of Mines), Dhanbad-826004, Jharkhand, India.
  - Mritunjay Kumar Singh, Department of Applied Mathematics, Indian Institute of Technology (Indian School of Mines), Dhanbad-826004, Jharkhand, India. (Corresponding author. Tel.: Fax.: Email: drmks29@rediffmail.com)