J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 243 - 254, doi: 10.2478/johh-2021-0017
Scientific Paper, English

Pritam Malakar, Ratul Das: Relative role of sediment entrainments on log-law parameters of longitudinal velocity distributions in mobile bed flows

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• In alluvial channel, the non-cohesive bed particles are frequently accelerated by the flows and there has been an inconclusive debate on the deviations of logarithmic law parameters that demonstrate the velocity distributions in flows. Present study aims to elucidate the current knowledge of overwhelming theoretical and experimental evidences in this regard within the scope of near-bed turbulent flow characteristics. The study was conducted in two folds collecting instantaneous velocity of flow over a rigid sand bed under clear water flow conditions and compared to those over mobile sand beds under equilibrium bed-load. Results corroborated additional support to confirm the upward shifting of zero-velocity level in mobile bed flows. Most importantly, the conventional value of von Kármán coefficient significantly deviates in mobile bed flows compared to those in rigid sand bed. Also, the frictional velocity obtained from the bed slope consistently differs to those obtained from the Reynolds shear stress (RSS) distributions owing to transfer of stress aliquot to the bed particles. The mechanism is well demonstrated with the energy-momentum transfer within the framework of energy budget concept which shows near-bed negative pressure energy diffusion rates with increasing turbulence production in mobile bed flows.
  
  KEY WORDS: Alluvial channel; Energy budget; Hydrodynamics; Mobile bed; Zero-velocity level.
  
  Address:
  - Pritam Malakar, Civil Engineering Department, National Institute of Technology Agartala, Agartala-799046, India. (Corresponding author. Tel.:+91 8131054353 Fax.: Email: pritam.its@gmail.com)
  - Ratul Das, Civil Engineering Department, National Institute of Technology Agartala, Agartala-799046, India.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 255 - 262, doi: 10.2478/johh-2021-0013
Scientific Paper, English

Václav Matoušek, Andrew Chryss, Lionel Pullum: Modelling vertical concentration distributions of solids suspended in turbulent visco-plastic fluid

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• Vertical concentration distributions of solids conveyed in Newtonian fluids can be modelled using Rouse- Schmidt type distributions. Observations of solids conveyed in turbulent low Reynolds number visco-plastic carriers, suggest that solids are more readily suspended than their Newtonian counterparts, producing higher concentrations in the centre of the pipe. A Newtonian concentration profile model was adapted to include typical turbulent viscosity distributions within the pipe and particle motion calculated using non-Newtonian sheared settling. Predictions from this and the unmodified model, using the same wall viscosity, are compared with the chord averaged profile extracted from tomographic data obtained using a 50 mm horizontal pipe.
  
  KEY WORDS: Complex slurry flow; Non-Newtonian flow; Solids distribution; Pipe flow; Particle settling; Laboratory experiment.
  
  Address:
  - Václav Matoušek, Czech Technical University in Prague, Faculty of Civil Engineering, Department of Hydraulics and Hydrology, Thákurova 7, 166 29 Praha 6, Czech Republic. (Corresponding author. Tel.: Fax.: Email: v.matousek@fsv.cvut.cz)
  - Andrew Chryss, CSIRO Mineral Resources, Bayview Avenue, Clayton, Victoria 3168, Australia.
  - Lionel Pullum, 29 Monash Avenue, Olinda, Victoria 3788, Australia.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 263 - 274, doi: 10.2478/johh-2021-0011
Scientific Paper, English

Thijs Schouten, Cees van Rhee, Geert Keetels: Two-phase modelling for sediment water mixtures above the limit deposit velocity in horizontal pipelines

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• In dredging applications, deep sea mining and land reclamation projects typically large amounts of sediments are transported through pipes in the form of hyper concentrated (40% sediment or more) sediment-water mixtures or slurries. In this paper it is investigated how well a generic Euler-Euler CFD-model is capable to model velocity, concentration profiles and the pressure gradient of sediment above deposition limit velocity in a pipeline. This Euler- Euler solver treats both phases as a continuum with its own momentum and continuity equations. The full kinetic theory for granular flows is accounted for (no algebraic form is used) and is combined with a buoyant k-ε turbulence model for the fluid phase. The influence of the mesh size has been checked and grid convergence is achieved. All numerical schemes used are of second-order accuracy in space. The pressure gradient was calibrated by adjusting the specularity coefficient in one calibration case and kept constant afterwards. Simulations were carried out in a wide range of slurry flow parameters, in situ volume concentration (9–42%), pipe diameter (0.05–0.90 m), particle diameter (90–440 μm) and flow velocity of (3–7 m/s). The model shows satisfactory agreement to experimental data from existing literature.
  
  KEY WORDS: Slurry flow; Two-phase modelling; CFD; Kinetic theory.
  
  Address:
  - Thijs Schouten, Section Offshore and Dredging Engineering, Delft University of Technology, Mekelweg 2, Delft, Netherlands. (Corresponding author. Tel.:+31 15 27 84461 Fax.: Email: T.D.Schouten@tudelft.nl)
  - Cees van Rhee, Section Offshore and Dredging Engineering, Delft University of Technology, Mekelweg 2, Delft, Netherlands.
  - Geert Keetels, Section Offshore and Dredging Engineering, Delft University of Technology, Mekelweg 2, Delft, Netherlands.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 275 - 287, doi: 10.2478/johh-2021-0014
Scientific Paper, English

Jun Wang, Zhixing Hou, Hongjian Sun, Bihe Fang, Jueyi Sui, Bryan Karney: Local scour around a bridge pier under ice-jammed flow condition – an experimental study

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• The appearance of an ice jam in a river crucially distorts local hydrodynamic conditions including water level, flow velocity, riverbed form and local scour processes. Laboratory experiments are used for the first time here to study ice-induced scour processes near a bridge pier. Results show that with an ice sheet cover the scour hole depth around a bridge is increased by about 10% compared to under equivalent open flow conditions. More dramatically, ice-jammed flows induce both greater scour depths and scour variability, with the maximum scour depth under an ice-jammed flow as much as 200% greater than under equivalent open flow conditions. Under an ice-jammed condition, both the maximum depth and length of scour holes around a bridge pier increase with the flow velocity while the maximum scour hole depth increases with ice-jam thickness. Also, quite naturally, the height of the resulting deposition dune downstream of a scour hole responds to flow velocity and ice jam thickness. Using the laboratory data under ice-jammed conditions, predictive relationships are derived between the flow’s Froude number and both the dimensionless maximum scour depth and the dimensionless maximum scour length.
  
  KEY WORDS: Ice jam; Ice cover; Riverbed deformation; Local scour; Bridge pier.
  
  Address:
  - Jun Wang, College of Civil and Hydraulic Engineering, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui, China.
  - Zhixing Hou, College of Civil and Hydraulic Engineering, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui, China.
  - Hongjian Sun, College of Civil and Hydraulic Engineering, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui, China.
  - Bihe Fang, College of Civil and Hydraulic Engineering, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui, China.
  - Jueyi Sui, School of Engineering, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada. (Corresponding author. Tel.: Fax.: Email: Jueyi.sui@unbc.ca)
  - Bryan Karney, Department of Civil Engineering, University of Toronto, Canada.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 288 - 299, doi: 10.2478/johh-2021-0015
Scientific Paper, English

Pavla Pekárová, Jakub Mészáros, Pavol Miklánek, Ján Pekár, Cyril Siman, Jana Podolinská: Post-flood field investigation of the June 2020 flash flood in the upper Muráň River basin and the catastrophic flash flood scenario

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• After a dry spring, in June 2020 several intense storms occurred at the headwaters of the small basins of the Muráň and Zdychava rivers in the territory of the Muránska planina National Park (Slaná River basin, Slovakia). In the first part of the study– according to a hydrological survey made by the authors after the flash flood – the peak discharge was reconstructed at several Muráň River profiles. Next, the flash flood waves were reconstructed by the rainfall-runoff model NLC (non-linear cascade). The results of modelling based on field investigations show that, despite the extreme precipitation event (108 mm per 1 hour at the precipitation gauging station at Predná Hora), the peak flow rates were not exceptional in selected profiles on the Muráň River. The fact that extreme precipitation above 120 mm fell in a relatively very small area at the division of the Muráň and Zdychava rivers’ water contributed to this result. In the second part, a catastrophic 1000-year rainfall event scenario on the Zdychava River basin has been prepared. In analysing time series and identifying T-year daily rainfall depths, daily data was used from six precipitation stations in the vicinity of Muránska planina. Then, the 1000-year discharge of the Zdychava at Revúca was simulated by the calibrated NLC model. In such an extreme precipitation scenario, the peak flow rate would reach 105.15 m3 s–1, i.e. with a specific runoff of 1.78 m3 s–1 km–2. The total runoff in an 18-hour period would be 1.119 million m3, representing 21.11% of the rainfall (5.301 million m3).
  
  KEY WORDS: Flash flood; Small basins; Rainfall-runoff NLC model; Catastrophic precipitation and flood scenario.
  
  Address:
  - Pavla Pekárová, Slovak Academy of Sciences, Institute of Hydrology, Dúbravská cesta 9, 841 04 Bratislava, Slovak Republic. (Corresponding author. Tel.: Fax.: Email: Pavla.Pekarova@savba.sk)
  - Jakub Mészáros, Slovak Academy of Sciences, Institute of Hydrology, Dúbravská cesta 9, 841 04 Bratislava, Slovak Republic.
  - Pavol Miklánek, Slovak Academy of Sciences, Institute of Hydrology, Dúbravská cesta 9, 841 04 Bratislava, Slovak Republic.
  - Ján Pekár, Comenius University in Bratislava, Faculty of Mathematics, Physics, and Informatics, Department of Applied Mathematics and Statistics, Mlynská dolina, 842 48 Bratislava, Slovak Republic.
  - Cyril Siman, Slovak Academy of Sciences, Institute of Hydrology, Dúbravská cesta 9, 841 04 Bratislava, Slovak Republic. Slovak Hydrometeorological Institute, Jeséniova 17, 833 15 Bratislava, Slovak Republic.
  - Jana Podolinská, Slovak Hydrometeorological Institute, Jeséniova 17, 833 15 Bratislava, Slovak Republic.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 300 - 310, doi: 10.2478/johh-2021-0016
Scientific Paper, English

Viktor Vyshnevskyi, Serhii Shevchuk: Thermal regime of the Dnipro Reservoirs

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• Based on the results of regular monitoring and remote sensing data the patterns of water temperature of the reservoirs cascade on the Dnipro River were identified. A characteristic feature of the thermal regime of the Dnipro Cascade has been the water temperature increase over the past decades. In the period 1977–2020 the water temperature in summer increased by 0.74 °C decade–1, and during May–October by 0.65 °C decade–1. An important factor influencing the thermal regime of the reservoirs is the influence of those ones, located upstream. Water from them is discharged from the lower layer, where the processes of heating and cooling are very slow. This has a significant influence on the water temperature of downstream reservoirs, especially on their upper part. The water temperature in this part during spring and summer seasons is lower compared to natural conditions. In autumn it is higher. The temperature of water also depends on the latitude: it rises in the reservoirs located both downstream and to the south. Another important factor influencing the water temperature is the wind, which can change the temperature in the surface layer by 5–6 °С. Water temperature also depends on the intensity of algae bloom – it is higher in the spots of a large bloom.
  
  KEY WORDS: Water temperature; The reservoirs cascade; The Dnipro River; Regular monitoring; Remote sensing data.
  
  Address:
  - Viktor Vyshnevskyi, National Aviation University, 1, Liubomyra Huzara Av., Kyiv, 03058, Ukraine. (Corresponding author. Tel.:+380662322337 Fax.: Email: vishnev.v@gmail.com)
  - Serhii Shevchuk, Institute of Water Problems and Land Reclamation, 37, Vasylkivska Str., Kyiv, 03022, Ukraine.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 311 - 318, doi: 10.2478/johh-2021-0019
Scientific Paper, English

Assefa D. Zegeye, Misganew Fentahun, Tilashwork C. Alemie, Tadele Amare: A low-cost subsurface drainage technique to enhance gully bank stability in the sub-humid highlands of Ethiopia

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• Gully erosion is the leading cause of elevated sediment yields in the world. Few low-cost techniques are available for rehabilitating gullies. The objective of this research was to evaluate the applicability of a low-cost horizontal sub-surface drainage system for decreasing gully erosion by stabilizing gully banks. The study was conducted in the subhumid Ethiopian highlands in two active gullies, one in a Vertisol and another in a Nitisol. One bank was drained with a plastic pipe, and the other bank acted as the control. The two opposite banks are hydrologically isolated from one another. The surrounding groundwater tables were continuously monitored for two years. Over two wet seasons, the average bank retreat in the Vertisol gully was 0.62 m for the control and 0.15 m for the drained bank. Similarly, in the Nitisol gully, in 1.1 m for the control and 0.29 m for the drained bank. The average groundwater table of the drained bank was 20% lower than the non-drained banks during the monitoring periods. These results suggest that bank dewatering maintained higher levels of stability of gully banks and promoted lower rates of bank retreat on both soil types. The initial cost of the dewatering treatments was significantly less than the conventional bank stabilization measures. Bank dewatering could be one of the technologies for gully rehabilitation. Gully management techniques in Ethiopia and elsewhere could benefit from integrating bank drainage with other physical and biological protective measures.
  
  KEY WORDS: Ethiopian highlands; Debre Mawi; Gully; Bank retreat; Dewatering; Erosion.
  
  Address:
  - Assefa D. Zegeye, Amhara Agricultural Research Institute, Adet Agricultural Research Center, Adet, Ethiopia. (Corresponding author. Tel.:+251 918 71 3709 Fax.: Email: assederebe@gmail.com)
  - Misganew Fentahun, Amhara Agricultural Research Institute, Adet Agricultural Research Center, Adet, Ethiopia.
  - Tilashwork C. Alemie, Amhara Agricultural Research Institute, Adet Agricultural Research Center, Adet, Ethiopia.
  - Tadele Amare, Amhara Agricultural Research Institute, Adet Agricultural Research Center, Adet, Ethiopia.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 319 - 331, doi: 10.2478/johh-2021-0020
Scientific Paper, English

Elizeu Melo da Silva, Joao N. N. Quaresma, Emanuel N. Macedo, Renato M. Cotta: Integral transforms for three-dimensional pumping in confined, leaky, and unconfined aquifers

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• Analytical or hybrid numerical-analytical solutions based on the Generalized Integral Transform Technique (GITT) are obtained for the transient three-dimensional pumping problem of aquifers with a fully penetrating vertical well between two parallel streams. The problem formulation for confined and leaky aquifers allows for achieving exact analytical solutions through integral transforms, while the unconfined aquifer case introduces a fourth kind boundary condition which leads to a coupled transformed head ordinary differential system, that can be solved either analytically or numerically. A convergence analysis is performed to illustrate the consistency of the numerical results achieved for the head distribution, as well as for the related pumping rates. Results are obtained for selected cases and comparisons with literature results are performed. A solution verification confirms the agreement of the integral transform solutions with available simulations and provides additional confidence for the analysis of a few physical parameters that influence the hydrological behavior.
  
  KEY WORDS: Integral transforms; Hybrid methods; Aquifer pumping problem; Head distribution; Stream depletion rate.
  
  Address:
  - Elizeu Melo da Silva, Graduate Program in Natural Resources Engineering in the Amazon, PRODERNA/ITEC/UFPA, Universidade Federal do Pará, 66075-110, Belém, PA, Brazil. School of Mining Engineering, UNIFESSPA, Universidade Federal do Sul e Sudeste do Pará, CEP 68505-080, Marabá, PA, Brazil.
  - Joao N. N. Quaresma, Graduate Program in Natural Resources Engineering in the Amazon, PRODERNA/ITEC/UFPA, Universidade Federal do Pará, 66075-110, Belém, PA, Brazil. School of Chemical Engineering, FEQ/ITEC/UFPA, Universidade Federal do Pará, 66075-110, Belém, PA, Brazil. (Corresponding author. Tel.: Fax.: Email: quaresma@ufpa.br)
  - Emanuel N. Macedo, Graduate Program in Natural Resources Engineering in the Amazon, PRODERNA/ITEC/UFPA, Universidade Federal do Pará, 66075-110, Belém, PA, Brazil. School of Chemical Engineering, FEQ/ITEC/UFPA, Universidade Federal do Pará, 66075-110, Belém, PA, Brazil.
  - Renato M. Cotta, General Directorate of Nuclear and Technological Development, DGDNTM, Marinha do Brasil, Rio de Janeiro, RJ, Brazil. Department of Mechanical Engineering, POLI & COPPE, CT, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 332 - 346, doi: 10.2478/johh-2021-0018
Scientific Paper, English

Larissa Virgínia da Silva Ribas, Artur Paiva Coutinho, Laurent Lassabatere, Severino Martins dos Santos Neto, Suzana Maria Gico Lima Montenegro, Ana Emília Carvalho de Gusmao da Cunha Rabelo, Rafael Angulo Jaramillo, Alfredo Ribeiro Neto: Effect of the choice of different methods on the permeable pavement hydraulic characterization and hydrological classification

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• The permeable pavement is a compensatory drainage technique for urban waters that aims to control runoff and to ensure ideal hydrological conditions. This work had as main objectives to evaluate the infiltration capacity of a permeable pavement (PP) at real scale, through analytical and numerical modeling. It relies on water infiltration experiments and related modeling for the hydrodynamic characterization of the coating layer (saturated hydraulic conductivity, Ks, and sorptivity, S). A large panel of analytical and numerical models was considered, and several estimates were obtained. Then, the criteria for the evaluation of the maintenance requirement of the permeable pavements were computed for all the Ks-estimates considering the NCRS standards (assessment of permeability levels). The results indicated nice fits and accurate estimates for both the saturated hydraulic conductivity and the sorptivity. However, the Ks-estimates depended on the considered model and led to contrasting results in terms of classification. For 8 of the 9 models, the value of the Ks-estimate leads to the classification of "Group A" of the NCRS soil classification, meaning a very permeable material. In contrasts, the last method (numerical inverse modeling) classified the permeable pavement as "Group D", i.e., soils with low permeability. Those results show the importance of the selection of characterization methods regarding the assessment of the hydrological classification of permeable pavements.
  
  KEY WORDS: Water infiltration techniques; Hydraulic conductivity; Compensatory techniques; Analytical methods; Numerical inversion; Hydrodynamic indicators.
  
  Address:
  - Larissa Virgínia da Silva Ribas, Department of Transport Engineering and Geodesy, Federal University of Bahia, BA, Brazil.
  - Artur Paiva Coutinho, Agreste Academic Center, 2 – Federal University of Pernambuco, PE, Brazil.
  - Laurent Lassabatere, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR5023 LEHNA, F-69518, Vaulx-en-Velin, France. (Corresponding author. Tel.: Fax.: Email: laurent.lassabatere@entpe.fr)
  - Severino Martins dos Santos Neto, Agreste Academic Center, 2 – Federal University of Pernambuco, PE, Brazil.
  - Suzana Maria Gico Lima Montenegro, Department of Civil and Environmental Engineering, Federal University of Pernambuco, Recife, Brazil.
  - Ana Emília Carvalho de Gusmao da Cunha Rabelo, Agreste Academic Center, 2 – Federal University of Pernambuco, PE, Brazil.
  - Rafael Angulo Jaramillo, Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR5023 LEHNA, F-69518, Vaulx-en-Velin, France.
  - Alfredo Ribeiro Neto, Department of Civil and Environmental Engineering, Federal University of Pernambuco, Recife, Brazil.

J. Hydrol. Hydromech., Vol. 69, No. 3, 2021, p. 347 - 355, doi: 10.2478/johh-2021-0012
Scientific Paper, English

Peter Šurda, Ľubomír Lichner, Jozef Kollár, Anton Zvala, Dušan Igaz: Evaluation of soil properties in variously aged Scots pine plantations established on sandy soil

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• Pines are widely planted for sand dune stabilization and their cultivation results in the changes in physical, chemical, hydro-physical and water repellency properties. Soil properties were evaluated at three Scots pine plantations (PF1, PF2 and PF3) close to Studienka village, Borská nížina lowland (southwestern Slovakia) during hot and dry summer period. The PF1 site is a newly established plantation, the PF2 site is about 30 years old plantation, and the PF3 site is about 100 years old plantation. Here, we estimated the differences in pH, soil organic carbon content, Cox, particle size distribution, PSD, saturated, ks, and unsaturated, k(–2 cm), hydraulic conductivity, water, Sw, and ethanol, Se, sorptivity, water drop penetration time, WDPT, and repellency index, RI. It was found that Cox varies most significantly with plantation age, and relative differences in PSD and pH were lower than the relative difference in Cox. The PF3 site differs the most from the other two, especially in Cox and in the content of sand fraction. It can be attributed to the older age of the plantation, which represents a more advanced stage of succession accompanied by an accumulation of soil organic matter. Relationships between Cox, k(–2 cm), RI, and WDPT and pine forest age were described by appropriate mathematical models. We found a similarity between k(–2 cm) and RI relationships vs. pine forest age (exponential models), and between Cox and WDPT relationships vs. pine forest age (first and second-order polynomial models). The latter similarity can be supported by the fact that soil water repellency is induced by the hydrophobic and amphiphilic components of soil organic matter.
  
  KEY WORDS: Sandy soil; Scots pine; Plantation; Forest restoration; Soil water repellency; Soil hydrophysical properties.
  
  Address:
  - Peter Šurda, Institute of Hydrology, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84104 Bratislava, Slovakia. (Corresponding author. Tel.: Fax.: Email: surda@uh.savba.sk)
  - Ľubomír Lichner, Institute of Hydrology, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84104 Bratislava, Slovakia.
  - Jozef Kollár, Institute of Landscape Ecology, Slovak Academy of Sciences, Štefánikova 3, SK-81499 Bratislava, Slovakia.
  - Anton Zvala, Institute of Hydrology, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84104 Bratislava, Slovakia.
  - Dušan Igaz, Department of Biometeorology and Hydrology, Faculty of Horticulture and Landscape Engineering, Slovak University of Agriculture, Tr. A. Hlinku 2, SK-94901 Nitra, Slovakia.