J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 297 - 304, doi: 10.2478/johh-2019-0018
Scientific Paper, English

Gabriel Minea, Gabriela Ioana-Toroimac, Gabriela Moroşanu: The dominant runoff processes on grassland versus bare soil hillslopes in a temperate environment - An experimental study

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• This paper aimed to investigate the dominant runoff processes (DRP’s) at plot-scale in the Curvature Subcarpathians under natural rainfall conditions characteristic for Romania’s temperate environment. The study was based on 32 selected rainfall-runoff events produced during the interval April–September (2014– 2017). By comparing water balance on the analyzed Luvisol plots for two types of land use (grassland vs. bare soil), we showed that DRP’s are mostly formed by Hortonian Overland Flow (HOF), 47% vs. 59% respectively. On grassland, HOF is followed by Deep Percolation (DP, 31%) and Fast Subsurface Flow (SSF, 22%), whereas, on bare soil, DP shows a higher percentage (38%) and SSF a lower one (3%), which suggests that the soil-root interface controls the runoff generation. Concerning the relationship between antecedent precipitation and runoff, the study indicated the nonlinearity of the two processes, more obvious on grassland and in drought conditions than on bare soil and in wet conditions (as demonstrated by the higher runoff coefficients). Moreover, the HOF appeared to respond differently to rainfall events on the two plots - slightly longer lag-time, lower discharge and lower volume on grassland - which suggests the hydrologic key role of vegetation in runoff generation processes.
  
  KEY WORDS: Dominant runoff processes; Grassland; Soil water balance plot; Rainfall-runoff event.
  
  Address:
  - Gabriel Minea, Research Institute of the University of Bucharest, University of Bucharest, 36-46 Bd. M. Kogălniceanu, Sector 5, 050107, Bucharest, Romania. National Institute of Hydrology and Water Management, 97 E Bucureşti - Ploieşti Road, Sector 1, 013686, Bucharest, Romania. (Corresponding author. Tel.:+40213181115 Fax.: +40213181116 Email: gabriel.minea@hidro.ro)
  - Gabriela Ioana-Toroimac, Faculty of Geography, University of Bucharest, 1 Nicolae Bălcescu Avenue, Sector 1, 010041, Bucharest, Romania.
  - Gabriela Moroşanu, Faculty of Geography, University of Bucharest, 1 Nicolae Bălcescu Avenue, Sector 1, 010041, Bucharest, Romania. Institute of Environmental Sciences, University of Grenoble Alpes, CS 40700, 38058 Grenoble Cedex 9, France. Institute of Geography, Romanian Academy, 12 Dimitrie Racovită, Sector 2, 023994, Bucharest, Romania.

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 305 - 313, doi: 10.2478/johh-2019-0019
Scientific Paper, English

Senlin Zhu, Ognjen Bonacci, Dijana Oskoruš, Marijana Hadzima-Nyarko, Shiqiang Wu: Long term variations of river temperature and the influence of air temperature and river discharge: case study of Kupa River watershed in Croatia

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• The bio-chemical and physical characteristics of a river are directly affected by water temperature, which therefore affects the overall health of aquatic ecosystems. In this study, long term variations of river water temperatures (RWT) in Kupa River watershed, Croatia were investigated. It is shown that the RWT in the studied river stations increased about 0.0232–0.0796ºC per year, which are comparable with long term observations reported for rivers in other regions, indicating an apparent warming trend. RWT rises during the past 20 years have not been constant for different periods of the year, and the contrasts between stations regarding RWT increases vary seasonally. Additionally, multilayer perceptron neural network models (MLPNN) and adaptive neuro-fuzzy inference systems (ANFIS) models were implemented to simulate daily RWT, using air temperature (Ta), flow discharge (Q) and the day of year (DOY) as predictors. Results showed that compared to the individual variable alone with Ta as input, combining Ta and Q in the MLPNN and ANFIS models explained temporal variations of daily RWT more accurately. The best accuracy was achieved when the three inputs (Ta, Q and the DOY) were included as predictors. Modeling results indicate that the developed models can well reproduce the seasonal dynamics of RWT in each river, and the models may be used for future projections of RWT by coupling with regional climate models.
  
  KEY WORDS: Climate change; Machine learning models; River water temperature.
  
  Address:
  - Senlin Zhu, State Key Laboratory of Hydrology-Water resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China.
  - Ognjen Bonacci, Faculty of Civil Engineering and Architecture, University of Split, Matice hrvatske 15, 21000 Split, Croatia.
  - Dijana Oskoruš, Meteorological and Hydrological Service, Gric 3, 10000 Zagreb, Croatia.
  - Marijana Hadzima-Nyarko, Josip Juraj Strossmayer University of Osijek, Faculty of Civil Engineering and Architecture Osijek, Vladimira Preloga 3, 31000 Osijek, Croatia. (Corresponding author. Tel.: Fax.: Email: mhadzima@gfos.hr)
  - Shiqiang Wu, State Key Laboratory of Hydrology-Water resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China.

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 314 - 321, doi: 10.2478/johh-2019-0021
Scientific Paper, English

Tomas Kozel, Milos Stary: Adaptive stochastic management of the storage function for a large open reservoir using an artificial intelligence method

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• The design and evaluation of algorithms for adaptive stochastic control of reservoir function of the water reservoir using artificial intelligence methods (learning fuzzy model and neural networks) are described in this article. This procedure was tested on an artificial reservoir. Reservoir parameters have been designed to cause critical disturbances during the control process, and therefore the influences of control algorithms can be demonstrated in the course of controlled outflow of water from the reservoir. The results of the stochastic adaptive models were compared. Further, stochastic model results were compared with a resultant course of management obtained using the method of classical optimisation (differential evolution), which used stochastic forecast data from real series (100% forecast). Finally, the results of the dispatcher graph and adaptive stochastic control were compared. Achieved results of adaptive stochastic management provide inspiration for continuing research in the field.
  
  KEY WORDS: Stochastic; Artificial intelligence; Storage function; Optimisation.
  
  Address:
  - Tomas Kozel, Brno University of Technology, Faculty of Civil Engineering, Institute of Landscape Water Management, Veveří 331/95, Brno, Czech Republic. (Corresponding author. Tel.: Fax.: Email: kozel.t@fce.vutbr.cz)
  - Milos Stary, Brno University of Technology, Faculty of Civil Engineering, Institute of Landscape Water Management, Veveří 331/95, Brno, Czech Republic.

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 322 - 328, doi: 10.2478/johh-2019-0014
Scientific Paper, English

Jaromír Říha, David Duchan, Zbyněk Zachoval, Sébastien Erpicum, Pierre Archambeau, Michel Pirotton, Benjamin Dewals: Performance of a shallow-water model for simulating flow over trapezoidal broad-crested weirs

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• Shallow-water models are standard for simulating flow in river systems during floods, including in the nearfield of sudden changes in the topography, where vertical flow contraction occurs such as in case of channel overbanking, side spillways or levee overtopping. In the case of stagnant inundation and for frontal flow, the flow configurations are close to the flow over a broad-crested weir with the trapezoidal profile in the flow direction (i.e. inclined upstream and downstream slopes). In this study, results of shallow-water numerical modelling were compared with seven sets of previous experimental observations of flow over a frontal broad-crested weir, to assess the effect of vertical contraction and surface roughness on the accuracy of the computational results. Three different upstream slopes of the broad-crested weir (V:H = 1:Z1 = 1:1, 1:2, 1:3) and three roughness scenarios were tested. The results indicate that, for smooth surface, numerical simulations overestimate by about 2 to 5% the weir discharge coefficient. In case of a rough surface, the difference between computations and observations reach up to 10%, for high relative roughness. When taking into account mentioned the differences, the shallow-water model may be applied for a range of engineering purposes.
  
  KEY WORDS: Discharge coefficient; Frontal broad-crested weir; Shallow flow modelling; Rough weir crest.
  
  Address:
  - Jaromír Říha, Faculty of Civil Engineering, Brno University of Technology, Brno, Czech Republic. (Corresponding author. Tel.: Fax.: Email: riha.j@fce.vutbr.cz)
  - David Duchan, Faculty of Civil Engineering, Brno University of Technology, Brno, Czech Republic.
  - Zbyněk Zachoval, Faculty of Civil Engineering, Brno University of Technology, Brno, Czech Republic.
  - Sébastien Erpicum, Hydraulics in Environmental and Civil Engineering (HECE), Research unit Urban & Environmental Engineering, University of Liege (ULiege), Belgium.
  - Pierre Archambeau, Hydraulics in Environmental and Civil Engineering (HECE), Research unit Urban & Environmental Engineering, University of Liege (ULiege), Belgium.
  - Michel Pirotton, Hydraulics in Environmental and Civil Engineering (HECE), Research unit Urban & Environmental Engineering, University of Liege (ULiege), Belgium.
  - Benjamin Dewals, Hydraulics in Environmental and Civil Engineering (HECE), Research unit Urban & Environmental Engineering, University of Liege (ULiege), Belgium.

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 329 - 338, doi: 10.2478/johh-2019-0022
Scientific Paper, English

Zbyněk Zachoval, Jakub Major, Ladislav Roušar, Ján Rumann, Jan Šulc, Jan Jandora: Submergence coefficient of full-width sharp-edged broad-crested rectangular weirs

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• Full-width sharp-edged broad-crested rectangular weirs in the range 0.1 < h/L ≤ 0.3 situated in rectangular channels are frequently used in submerged flow conditions. To determine the discharge for the submerged flow, submergence coefficient and modular limit shall be known. This article deals with their determination upon a theoretic derivation and experimental research. The equation for modular limit has been determined from energy balance with simplifications. To validate it, extensive experimental research was carried out. However, the derived equation is too complicated for practical use which is why it was approximated by a simple equation applicable for the limited range. The equation for submergence coefficient was derived by modifying Villemonte's application of the principle of superposition and its coefficients were determined using the data from experimental research of many authors. The new system of equations computes the discharge more accurately than other authors' equations, with the error of approximately ±10% in full range of the measured data.
  
  KEY WORDS: Modular limit; Relative weir height; Full-width sharp-edged broad-crested weir; Submergence coefficient.
  
  Address:
  - Zbyněk Zachoval, Brno University of Technology, Faculty of Civil Engineering, Institute of Water Structures, Veveří 331/95, 602 00 Brno, Czech Republic. (Corresponding author. Tel.: Fax.: Email: zachoval.z@fce.vutbr.cz)
  - Jakub Major, Brno University of Technology, Faculty of Civil Engineering, Institute of Water Structures, Veveří 331/95, 602 00 Brno, Czech Republic.
  - Ladislav Roušar, VHRoušar, Radčice 24, 539 73 Skuteč, Czech Republic.
  - Ján Rumann, Slovak University of Technology in Bratislava, Faculty of Civil Engineering, Department of Hydraulic Engineering, Radlinského 11, 810 05 Bratislava, Slovak Republic.
  - Jan Šulc, Brno University of Technology, Faculty of Civil Engineering, Institute of Water Structures, Veveří 331/95, 602 00 Brno, Czech Republic.
  - Jan Jandora, Brno University of Technology, Faculty of Civil Engineering, Institute of Water Structures, Veveří 331/95, 602 00 Brno, Czech Republic.

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 339 - 348, doi: 10.2478/johh-2019-0020
Scientific Paper, English

Ayman Allam, Esam Helal, Mahmoud Mansour: Retarding contaminant migration through porous media using inclined barrier walls

 Full Text in PDF     59 DOWNLOADS

• This study aims to assess the abilities of inclined barrier walls (BWs) to retard the migration of contaminants through porous media. Four cases of BW arrangements were considered, including a single inclined BW (BW1) and two adjacent BWs (BW1 and BW2) with different combinations of inclination ratios (i.e., I1 = θ1 /90° and I2 = θ2 /90°). Furthermore, the effect of the distance (L) between the contamination source and BW1 on the migration time (T) was evaluated. A numerical model (GeoStudio) containing two modules (SEEP/W and CTRAN/W) was used. The model proved its reliability to simulate contaminant migration through the porous media, where the normalized objective function values between the simulated and analytical results were 0.02 and 0.04 for the discharge of seepage and concentration of contamination, respectively. The results demonstrated that the migration time was strongly influenced by the inclination ratios of the BWs. Three-dimensional regression analysis was applied to demonstrate the combined effect of the inclination ratio, L and BW arrangements on T.
  
  KEY WORDS: Contaminant migration; Advection-diffusion; Inclined barrier walls; Finite element; GeoStudio.
  
  Address:
  - Ayman Allam, Civil Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafrelsheikh, Egypt. Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552, Japan. (Corresponding author. Tel.:+2-010-62056215 Fax.: Email: aymanallam82@eng.kfs.edu.eg)
  - Esam Helal, Civil Engineering Department, Faculty of Engineering, Menoufia University, Menoufia, Egypt.
  - Mahmoud Mansour, Civil Engineering Department, Faculty of Engineering, Menoufia University, Menoufia, Egypt.

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 349 - 358, doi: 10.2478/johh-2019-0016
Scientific Paper, English

Bing Bai, Zhenqian Zhai, Dengyu Rao: The seepage transport of heavy metal Pb2+ through sand column in the presence of silicon powders

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• The coupled transport of heavy metals with suspended particles has been a topic of growing interest. The main purpose of this study is to experimentally investigate the seepage transport of heavy metal Pb2+ in the presence of silicon powders (SPs) through a sand column under different seepage velocities (v = 0.087−0.260 cm/s), injection Pb2+ concentrations (CP = 0−800 μg/ml) and SP sizes (D50 = 2.8−25.5 μm), which were likely to be encountered in practical engineering. The sand column was installed in a cylindrical chamber of 300 mm in length and 80 mm in internal diameter. The results clearly show that the increase in acidity results in a reduction of the repulsive interactions between SPs and the matrix, and consequently a decrease in the peak values in breakthrough curves (BTCs), especially for larger-sized SPs. The peak values and recovery rate of Pb2+ are obviously increased and an earlier breakthrough can be observed, due to the higher capacity of SPs with negative charge to adsorb heavy metal pollutants such as Pb2+ with positive charge. The adsorption of Pb2+ on SPs can reduce the repulsive forces between SPs and the matrix, thus resulting in the increase of the deposition possibility of SPs and the decrease of peak value and recovery rate.
  
  KEY WORDS: Seepage transport; Silicon powder; Heavy metal; Coupled effect; Sand column.
  
  Address:
  - Bing Bai, School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, P R China. (Corresponding author. Tel.:+86 010 51684815 Fax.: Email: bbai@bjtu.edu.cn)
  - Zhenqian Zhai, School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, P R China.
  - Dengyu Rao, School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, P R China.

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 359 - 371, doi: 10.2478/johh-2019-0015
Scientific Paper, English

Theophilo B. Ottoni Filho, Marlon G. Lopes Alvarez, Marta V. Ottoni, Arthur Bernardo Barbosa Dib Amorim: Extension of the Gardner exponential equation to represent the hydraulic conductivity curve

 Full Text in PDF     48 DOWNLOADS

• The relative hydraulic conductivity curve Kr(h) = K/Ks is a key variable in soil modeling. This study proposes a model to represent Kr(h), the so-called Gardner dual (GD) model, which extends the classical Gardner exponential model to h values greater than ho, the suction value at the inflection point of the Kr(h) curve in the log-log scale. The goodness of fit of GD using experimental data from UNSODA was compared to that of the MVG [two-parameter (Kro, L) Mualem-van Genuchten] model and a corresponding modified MVG model (MVGm). In 77 soils without evidence of macropore flow, GD reduced the RMSE errors by 64% (0.525 to 0.191) and 29% (0.269 to 0.193) in relation to MVG and MVGm, respectively. In the remaining 76 soils, GD generally was less accurate than MVG and MVGm, since most of these soils presented evidence of macropore flow (dual permeability). GD has three parameters and two degrees of freedom, like MVG. Two of them allow the calculation of the macroscopic capillary length, a parameter from the infiltration literature. The three parameters are highly dependent on the Kr(h) data measurement in a short wet suction range around ho, which is an experimental advantage.
  
  KEY WORDS: Hydraulic conductivity curve; Gardner exponential model; Mualem-van Genuchten model.
  
  Address:
  - Theophilo B. Ottoni Filho, Department of Water Resources and Environment, Politechnical School, Federal Univ. of Rio de Janeiro (CT/UFRJ), Ilha do Fundao, Rio de Janeiro, RJ, Brazil. CEP: 21941-909
  - Marlon G. Lopes Alvarez, State Environmental Institute (INEA), Av. Venezuela 110, Saúde, Rio de Janeiro, RJ, Brazil. CEP:20081-312
  - Marta V. Ottoni, Department of Hydrology, Geological Survey of Brazil (CPRM), Av. Pasteur, 404, Urca, Rio de Janeiro, RJ, Brazil. CEP: 22290-240 (Corresponding author. Tel.:+55 21 2546 0352 Fax.: Email: marta.ottoni@cprm.gov.br)
  - Arthur Bernardo Barbosa Dib Amorim, Department of Water Resources and Environment, Politechnical School, Federal Univ. of Rio de Janeiro (CT/UFRJ), Ilha do Fundao, Rio de Janeiro, RJ, Brazil. CEP: 21941-909

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 372 - 383, doi: 10.2478/johh-2019-0009
Scientific Paper, English

William Godoy, Elizabeth M. Pontedeiro, Fernanda Hoerlle, Amir Raoof, Martinus Th. van Genuchten, José Santiago, Paulo Couto: Computational and experimental pore-scale studies of a carbonate rock sample

 Full Text in PDF     109 DOWNLOADS

• Carbonate rocks host several large water and hydrocarbon reservoirs worldwide, some of them highly heterogeneous involving complex pore systems. Pre-salt reservoirs in the Santos Basin off the south-east coast of Brazil, are an example of such rocks, with much attention focused on proper characterization of their petrophysical and multiphase flow properties. Since it is very difficult to obtain rock samples (coquinas) from these very deep reservoirs, analogues from north-eastern Brazil are often used because of very similar geological age and petrophysical properties. We used a coquina plug from an outcrop in a quarry in northeast Brazil to perform a comprehensive set of analyses. They included Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), and micro-computed tomography (μCT) image acquisition using a series of pixel sizes, as well as direct permeability/ porosity measurements. Some of the experimental data were collected from the plug itself, and some from a small sample of the rock slab, including thin sections. Results included the carbonate rock composition and the pore system at different scales, thus allowing us to reconstruct and model the porosity and absolute permeability of the coquina using 3D digital imaging and numerical simulations with pore network models (PNMs). The experimental and numerical data provided critical information about the well-connected pore network of the coquina, thereby facilitating improved predictions of fluid flow through the sample, with as ultimate objective to improve hydrocarbon recovery procedures.
  
  KEY WORDS: Pore network modeling; Carbonate rock; Coquina; Absolute permeability; µCT.
  
  Address:
  - William Godoy, Civil Engineering Program – PEC/COPPE – LRAP, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. (Corresponding author. Tel.: Fax.: Email: wmgodoy@petroleo.ufrj.br)
  - Elizabeth M. Pontedeiro, Civil Engineering Program – PEC/COPPE – LRAP, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands.
  - Fernanda Hoerlle, Civil Engineering Program – PEC/COPPE – LRAP, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
  - Amir Raoof, Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands.
  - Martinus Th. van Genuchten, Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands. Center for Environmental Studies, CEA, Sao Paulo University, UNESP, Rio Claro, SP, Brazil.
  - José Santiago, Civil Engineering Program – PEC/COPPE – LRAP, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
  - Paulo Couto, Civil Engineering Program – PEC/COPPE – LRAP, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.

J. Hydrol. Hydromech., Vol. 67, No. 4, 2019, p. 384 - 392, doi: 10.2478/johh-2019-0017
Scientific Paper, English

András Herceg, Reinhard Nolz, Péter Kalicz, Zoltán Gribovszki: Predicting impacts of climate change on evapotranspiration and soil moisture for a site with subhumid climate

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• The current and ongoing climate change over Europe can be characterized by statistically significant warming trend in all seasons. Warming has also an effect on the hydrological cycle through the precipitation intensity. Consequently, the supposed changes in the distribution and amount of precipitation with the continuously increasing temperature may induce a higher rate in water consumption of the plants, thus the adaptation of the plants to the climate change can be critical. The hydrological impact of climate change was studied based on typical environmental conditions of a specific agricultural area in Austria. For this purpose, (1) a monthly step, Thornthwaite-type water balance model was established and (2) the components of the water balance were projected for the 21st century, both (a) with a basic rooting depth condition (present state) and (b) with a (hypothetically) extended rooting depth (in order to evaluate potential adaption strategies of the plants to the warming). To achieve the main objectives, focus was set on calibrating and validating the model using local reference data. A key parameter of the applied model was the water storage capacity of the soil (SOILMAX), represented in terms of a maximum rooting depth. The latter was assessed and modified considering available data of evapotranspiration and soil physical properties. The adapted model was utilized for projections on the basis of four bias corrected Regional Climate Models. An extended rooting depth as a potential adaptation strategy for effects of climate change was also simulated by increasing SOILMAX. The basic simulation results indicated increasing evapotranspiration and soil moisture annual mean values, but decreasing minimum soil moisture for the 21st century. Seasonal examination, however, revealed that a decrease in soil moisture may occur in the growing season towards to the end of the 21st century. The simulations suggest that the vegetation of the chosen agricultural field may successfully adapt to the water scarcity by growing their roots to the possibly maximum.
  
  KEY WORDS: Water balance; Plant available water; Weighing lysimeter; Regional Climate Model.
  
  Address:
  - András Herceg, University of Sopron, Institute of Geomatics and Civil Engineering, Bajcsy-Zsilinszky s. 4, Sopron H-9400, Hungary. (Corresponding author. Tel.:+36 30 719 4527 Fax.: Email: herceg.andras88@gmail.com)
  - Reinhard Nolz, University of Natural Resources and Life Sciences, Vienna, Institute of Hydraulics and Rural Water Management, Muthgasse 18, 1190 Wien, Austria.
  - Péter Kalicz, University of Sopron, Institute of Geomatics and Civil Engineering, Bajcsy-Zsilinszky s. 4, Sopron H-9400, Hungary.
  - Zoltán Gribovszki, University of Sopron, Institute of Geomatics and Civil Engineering, Bajcsy-Zsilinszky s. 4, Sopron H-9400, Hungary.