J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 89 - 96, doi: 10.2478/johh-2014-0020
Scientific Paper, English

Shengqi Jian, Chuanyan Zhao, Shumin Fang, Kai Yu: Soil water content and water balance simulation of Caragana korshinskii Kom. in the semiarid Chinese Loess Plateau

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• In this paper, to evaluate the hydrological effects of Caragana korshinskii Kom., measured data were combined with model-simulated data to assess the C. korshinskii soil water content based on water balance equation. With measured and simulated canopy interception, plant transpiration and soil evaporation, soil water content was modeled with the water balance equation. The monthly variations in the modeled soil water content by measured and simulated components (canopy interception, plant transpiration, soil evaporation) were then compared with in situ measured soil water content. Our results shows that the modeled monthly water loss (canopy interception + soil evaporation + plant transpiration) by measured and simulated components ranges from 43.78 mm to 113.95 mm and from 47.76 mm to 125.63 mm, respectively, while the monthly input of water (precipitation) ranges from 27.30 mm to 108.30 mm. The relative error between soil water content modeled by measured and simulated components was 6.41%. To sum up, the net change in soil water (ΔSW) is negative in every month of the growing season. The soil moisture is approaching to wilting coefficient at the end of the growth season, and the soil moisture recovered during the following season.
  
  KEY WORDS: Shrub canopy; Interception; Transpiration; Soil evaporation; Water balance; Semiarid region.
  
  Address:
  - Shengqi Jian, State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Huyang building 301, Tianshui south road 222, Lanzhou, China.
  - Chuanyan Zhao, State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Huyang building 301, Tianshui south road 222, Lanzhou, China. (Corresponding author. Tel.:+86 13679458015 Fax.: Email: nanzhr@lzb.ac.cn)
  - Shumin Fang, State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Huyang building 301, Tianshui south road 222, Lanzhou, China. College of Resource and Environmental Sciences, Gansu Agricultural University, Forestry building 204, Yingmen village 1, Lanzhou, China.
  - Kai Yu, Ministry of Education Key Laboratory of Western China Environmental Systems, Lanzhou University, Huyang building 301, Tianshui south road 222, Lanzhou, China.

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 97 - 100, doi: 10.2478/johh-2014-0019
Scientific Paper, English

D.A.L. Leelamanie, Jutaro Karube: Water stable aggregates of Japanese Andisol as affected by hydrophobicity and drying temperature

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• Hydrophobicity is a property of soils that reduces their affinity for water, which may help impeding the pressure build-up within aggregates, and reducing aggregate disruption. The purpose of this study was to examine the relation of soil hydrophobicity and drying temperature to water stability of aggregates while preventing the floating of dry aggregates using unhydrophobized and hydrophobized surface Andisol. Soil was hydrophobized using stearic acid into different hydrophobicities. Hydrophobicity was determined using sessile drop contact angle and water drop penetration time (WDPT). Water stability of aggregates (%WSA) was determined using artificially prepared model aggregates. The %WSA increased as the contact angle and WDPT increased. Contact angle and WDPT, which provided maximum %WSA showing less than 1 s of floating, was around 100° and 5 s, respectively. Although the %WSA gradually increased with increasing contact angle and WDPT above this level, high levels of hydrophobicity initiated aggregate floating, which would cause undesirable effects of water repellency. Heating at 50°C for 5 h d–1 significantly affected %WSA and hydrophobicity in hydrophobized samples, but did not in unhydrophobized samples. The results indicate that the contact angle and wetting rate (WDPT) are closely related with the water stability of aggregates. The results further confirm that high levels of hydrophobicities induce aggregate floating, and the drying temperature has differential effects on hydrophobicity and aggregate stability depending on the hydrophobic materials present in the soil.
  
  KEY WORDS: Aggregate stability; Contact angle; Floating time; Japanese Andisol; Hydrophobicity; Wetting rate.
  
  Address:
  - D.A.L. Leelamanie, Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, Sri Lanka. (Corresponding author. Tel.:+94-71-861-4380 Fax.: +94-41-2292384 Email: leelamanie@soil.ruh.ac.lk, leelamaniee@yahoo.co.uk)
  - Jutaro Karube, Faculty of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami-machi, Ibaraki-ken 300-0393, Japan.

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 101 - 107, doi: 10.2478/johh-2014-0017
Scientific Paper, English

Elena Lozano, Fuensanta García-Orenes, Gema Bárcenas-Moreno, Patricia Jiménez-Pinilla, Jorge Mataix-Solera, Victoria Arcenegui, Alicia Morugán-Coronado, Jorge Mataix-Beneyto: Relationships between soil water repellency and microbial community composition under different plant species in a Mediterranean semiarid forest

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• Soil water repellency (SWR) can influence many hydrological soil properties, including water infiltration, uneven moisture distribution or water retention. In the current study we investigated how variable SWR persistence in the field is related to the soil microbial community under different plant species (P. halepensis, Q. rotundifolia, C. albidus and R. officinalis) in a Mediterranean forest. The soil microbial community was determined through phospholipid fatty acids (PLFA). The relationships between microbiological community structure and the soil properties pH, Glomalin Related Soil Protein (GRSP) and soil organic matter (SOM) content were also studied. Different statistical analyses were used: Principal Component Analysis (PCA), ANOVA, Redundancy Analysis and Pearson correlations. The highest concentrations of PLFA were found in the most water repellent samples. PCA showed that microorganism composition was more dependent of the severity of SWR than the type of plant species. In the Redundancy Analysis, SWR was the only significant factor (p<0.05) to explain PLFA distributions. The only PLFA biomarkers directly related to SWR were associated with Actinobacteria (10Me16:0, 10Me17:0 and 10Me18:0). All the results suggest that a strong dependence between SWR and microbial community composition.
  
  KEY WORDS: Soil hydrophobicity; Phospholipids fatty acids; Microbial community structure; Biohydrology; Actinobacteria; Glomalin Related Soil Protein.
  
  Address:
  - Elena Lozano, GEA (Grupo de Edafología Ambiental). Departamento de Agroquímica y Medio Ambiente, Universidad Miguel Hernández, Avenida de la Universidad s/n, 03202 Elche, Alicante, Spain. (Corresponding author. Tel.: Fax.: Email: elozano@umh.es)
  - Fuensanta García-Orenes, GEA (Grupo de Edafología Ambiental). Departamento de Agroquímica y Medio Ambiente, Universidad Miguel Hernández, Avenida de la Universidad s/n, 03202 Elche, Alicante, Spain.
  - Gema Bárcenas-Moreno, MEDSoil Research Group, Departamento de Cristalografía, Mineralogía y Química Agrícola, Facultad de Química, Universidad de Sevilla, Spain.
  - Patricia Jiménez-Pinilla, GEA (Grupo de Edafología Ambiental). Departamento de Agroquímica y Medio Ambiente, Universidad Miguel Hernández, Avenida de la Universidad s/n, 03202 Elche, Alicante, Spain.
  - Jorge Mataix-Solera, GEA (Grupo de Edafología Ambiental). Departamento de Agroquímica y Medio Ambiente, Universidad Miguel Hernández, Avenida de la Universidad s/n, 03202 Elche, Alicante, Spain.
  - Victoria Arcenegui, GEA (Grupo de Edafología Ambiental). Departamento de Agroquímica y Medio Ambiente, Universidad Miguel Hernández, Avenida de la Universidad s/n, 03202 Elche, Alicante, Spain.
  - Alicia Morugán-Coronado, SEDER. Department of Geography. University of Valencia. Blasco Ibanez, 28. 46010-Valencia, Spain.
  - Jorge Mataix-Beneyto, GEA (Grupo de Edafología Ambiental). Departamento de Agroquímica y Medio Ambiente, Universidad Miguel Hernández, Avenida de la Universidad s/n, 03202 Elche, Alicante, Spain.

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 108 - 116, doi: 10.2478/johh-2014-0015
Scientific Paper, English

Shatirah Akib, Afshin Jahangirzadeh, Hossein Basser: Local scour around complex pier groups and combined piles at semi-integral bridge

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• This research presents an experimental study on the scouring mechanism at semi-integral bridge piers. Based on laboratory experiments, this study focuses on the relationship between scour depth in complex pier groups and combined piles bridge and various parameters including the variation of inflow velocity, distance, and time. 1 200 data were collected for flow velocity and scour. The flow pattern and scour were analyzed for different flow discharges and flow depths. The results showed that the scour development with respect to time was greater for higher flow depth and bigger flow discharge at semi-integral bridges. In addition, the equilibrium scour depth increased with the approach flow depth around piers at semi-integral bridges. Velocity distribution also affected the scour development. It decreased when approaching the bridge but increased from upstream to downstream of the flume.
  
  KEY WORDS: Semi-integral Bridge; Complex pier groups; Combined Piles; Scour; Pier; Scour Depth.
  
  Address:
  - Shatirah Akib, Department of Civil Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia. (Corresponding author. Tel.: Fax.: Email: shatirah@um.edu.my; afshin.jk@gmail.com)
  - Afshin Jahangirzadeh, Department of Civil Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
  - Hossein Basser, Department of Civil Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 117 - 125, doi: 10.2478/johh-2014-0016
Scientific Paper, English

Tasawar Hayat, Sabir Ali Shehzad, Saleh Al-Mezel, Ahmed Alsaedi: Three-dimensional flow of an Oldroyd-B fluid over a bidirectional stretching surface with prescribed surface temperature and prescribed surface heat flux

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• This paper concentrates on the mathematical modelling for three-dimensional flow of an incompressible Oldroyd- B fluid over a bidirectional stretching surface. Mathematical formulation incorporates the effect of internal heat source/sink. Two cases of heat transfer namely the prescribed surface temperature (PST) and prescribed surface heat flux (PHF) are considered. Computations for the governing nonlinear flow are presented using homotopy analysis method. Comparison of the present analysis is shown with the previous limiting result. The obtained results are discussed by plots of interesting parameters for both PST and PHF cases. We examine that an increase in Prandtl number leads to a reduction in PST and PHF. It is noted that both PST and PHF are increased with an increase in source parameter. Further we have seen that the temperature is an increasing function of ratio parameter.
  
  KEY WORDS: Three-dimensional flow; Oldroyd-B fluid; Bidirectional stretching surface; Heat source/sink.
  
  Address:
  - Tasawar Hayat, Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000, Pakistan.
  - Sabir Ali Shehzad, Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000, Pakistan. (Corresponding author. Tel.: Fax.: Email: ali_qau70@yahoo.com)
  - Saleh Al-Mezel, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80257, Jeddah 21589, Saudi Arabia.
  - Ahmed Alsaedi, Department of Mathematics, Faculty of Science, King Abdulaziz University, P.O. Box 80257, Jeddah 21589, Saudi Arabia.

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 126 - 132, doi: 10.2478/johh-2014-0012
Scientific Paper, English

Jan Krupička, Václav Matoušek: Gamma-ray-based measurement of concentration distribution in pipe flow of settling slurry: vertical profiles and tomographic maps

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• Principles of gamma-ray-based measurement are summarized and their application is demonstrated on an op-eration of the radiometric facility installed in the test loop for slurry flows at the Institute of Hydrodynamics. The facility is able to measure vertical profiles of chord-averaged concentrations and concentration maps in the pipe cross section. A methodology of measurement is proposed including detection and quantification of random and systematic errors. Experimental results are discussed in the light of the proposed methodology. Experimentally determined vertical profiles of concentration are presented for slurry flows of four different fractions of glass beads. The tomographic application of the radiometric device is demonstrated on a measured concentration map and a suitable image reconstruction method is tested. High reliability of measured concentration distributions is proved except for regions near the pipe wall. The radiometric method is shown to be a useful tool for measurement of concentration distribution in slurry flow through a pipe.
  
  KEY WORDS: Two-phase flow; Gamma radiometry; Computational tomography; Slurry flow experiment.
  
  Address:
  - Jan Krupička, Institute of Hydrodynamics of the Academy of Sciences of the Czech Republic, v. v. i., Pod Paťankou 30/5, 166 12, Prague, Czech Republic. (Corresponding author. Tel.: Fax.: Email: krupicka@ih.cas.cz)
  - Václav Matoušek, Institute of Hydrodynamics of the Academy of Sciences of the Czech Republic, v. v. i., Pod Paťankou 30/5, 166 12, Prague, Czech Republic.

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 133 - 144, doi: 10.2478/johh-2014-0018
Scientific Paper, English

Song Song, Britta Schmalz, Nicola Fohrer: Simulation and comparison of stream power in-channel and on the floodplain in a German lowland area

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• Extensive lowland floodplains cover substantial parts of the glacially formed landscape of Northern Germany. Stream power is recognized as a force of formation and development of the river morphology and an interaction system between channel and floodplain. In order to understand the effects of the river power and flood power, HEC-RAS models were set up for ten river sections in the Upper Stör catchment, based on a 1 m digital elevation model and field data, sampled during a moderate water level period (September, 2011), flood season (January, 2012) and dry season (April, 2012). The models were proven to be highly efficient and accurate through the seasonal roughness modification. The coefficients of determination (R2) of the calibrated models were 0.90, 0.90, 0.93 and 0.95 respectively. Combined with the continuous and long-term data support from SWAT model, the stream power both in-channel and on the floodplain was analysed. Results show that the 10-year-averaged discharge and unit stream power were around 1/3 of bankfull discharge and unit power, and the 10-year-peak discharge and unit stream power were nearly 1.6 times the bankfull conditions. Unit stream power was proportional to the increase of stream discharge, while the increase rate of unit in-channel stream power was 3 times higher than that of unit stream power on the floodplain. Finally, the distribution of the hydraulic parameters under 10-years-peak discharge conditions was shown, indicating that only 1–10% of flow stream was generated by floodplain flow, but 40–75% volume of water was located on the floodplain. The variation of the increasing rate of the stream power was dominated by the local roughness height, while the stream power distributed on the floodplain mainly depended on the local slope of the sub-catchment.
  
  KEY WORDS: HEC-RAS model; In-channel flow; Floodplain flow; Unit stream power; Inundation area.
  
  Address:
  - Song Song, Department of Hydrology and Water Resources Management, Institute for Natural Resource Conservation, University of Kiel, Olshausenstr. 75, 24118 Kiel, Germany. (Corresponding author. Tel.:049-0431-8802725 Fax.: 049-0431-8804083 Email: ssong@hydrology.uni-kiel.de)
  - Britta Schmalz, Department of Hydrology and Water Resources Management, Institute for Natural Resource Conservation, University of Kiel, Olshausenstr. 75, 24118 Kiel, Germany.
  - Nicola Fohrer, Department of Hydrology and Water Resources Management, Institute for Natural Resource Conservation, University of Kiel, Olshausenstr. 75, 24118 Kiel, Germany.

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 145 - 149, doi: 10.2478/johh-2014-0014
Scientific Paper, English

Zbyněk Zachoval, Michaela Knéblová, Ladislav Roušar, Ján Rumann, Jan Šulc: Discharge coefficient of a rectangular sharp-edged broad-crested weir

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• This paper is concerned with the determination of the relationship for the calculation of the discharge coefficient at free overflow over a rectangular sharp-edged broad-crested weir without lateral contraction. The determination was made on the basis of new measurement in a range of the relative thickness of the weir from 0.12 to 0.30 and newly in a large range of relative height of the weir extremely from 0.24 to 6.8 which greatly expands the application possibilities of low weirs. In addition, the effects of friction and surface tension on the value of the discharge coefficient were evaluated as well as the effect of the relative thickness of the weir. The new equation for discharge coefficient, expressed using the relative height of the weir, was subjected to verification made by an independent laboratory which confirmed its accuracy.
  
  KEY WORDS: Broad-crested weir; Discharge coefficient; Relative height of weir.
  
  Address:
  - Zbyněk Zachoval, Laboratory of Water Management Research, Department of Water Structures, Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00, Brno, Czech Republic. (Corresponding author. Tel.: Fax.: Email: zachoval.z@fce.vutbr.cz)
  - Michaela Knéblová, Department of Water management Conceptions and Information, Odra River Board, Varenská 49, 701 26, Ostrava, Czech Republic.
  - Ladislav Roušar, Department of Water Structures, Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00, Brno, Czech Republic.
  - Ján Rumann, Department of Hydraulic Engineering, Faculty of Civil Engineering, Slovak University of Technology in Bratislava, Radlinského 11, 813 68, Bratislava, Slovak Republic.
  - Jan Šulc, Laboratory of Water Management Research, Department of Water Structures, Faculty of Civil Engineering, Brno University of Technology, Veveří 331/95, 602 00, Brno, Czech Republic.

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 150 - 159, doi: 10.2478/johh-2014-0013
Scientific Paper, English

Martin Bombač, Gorazd Novak, Primož Rodič, Matjaž Četina: Numerical and physical model study of a vertical slot fishway

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• This paper presents the results of an experimental and numerical study of a vertical slot fishway (VSF). A 2-D depth-averaged shallow water numerical model PCFLOW2D coupled with three different turbulent models (constant eddy viscosity, Smagorinsky and k – ε) was used. A detailed analysis of numerical parameters needed for a correct simulation of the phenomenon was carried out. Besides the velocity field, attention was paid to important hydraulic parameters such as maximum velocity in the slot region and energy dissipation rate ? in order to evaluate the performance of VSF. A scaled physical hydraulic model was built to ensure reliable experimental data for the validation of the numerical model. Simulations of variant configurations of VSF showed that even small changes in geometry can produce more fish-friendly flow characteristics in pools. The present study indicates that the PCFLOW2D program is an appropriate tool to meet the main demands of the VSF design.
  
  KEY WORDS: Eddy viscosity; Hydraulic model; Numerical diffusion; Numerical model PCFLOW2D; Turbulence model; Vertical slot fishway.
  
  Address:
  - Martin Bombač, Institute for Hydraulic Research, Hajdrihova 28, 1000, Ljubljana, Slovenia. (Corresponding author. Tel.: Fax.: Email: martin.bombac@hidroinstitut.si)
  - Gorazd Novak, Institute for Hydraulic Research, Hajdrihova 28, 1000, Ljubljana, Slovenia.
  - Primož Rodič, Institute for Hydraulic Research, Hajdrihova 28, 1000, Ljubljana, Slovenia.
  - Matjaž Četina, Chair of Fluid Mechanics with Laboratory, Faculty of Civil and Geodetic Engineering, University of Ljubljana, Hajdrihova 28, 1000, Ljubljana, Slovenia

J. Hydrol. Hydromech., Vol. 62, No. 2, 2014, p. 160 - 168, doi: 10.2478/johh-2014-0002
Scientific Paper, English

Alena Kulasova, Keith J. Beven, Sarka D. Blazkova, Daniela Rezacova, Jiri Cajthaml: Comparison of saturated areas mapping methods in the Jizera Mountains, Czech Republic

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• Understanding and modelling the processes of flood runoff generation is still a challenge in catchment hy-drology. In particular, there are issues about how best to represent the effects of the antecedent state of saturation of a catchment on runoff formation and flood hydrographs. This paper reports on the experience of mapping saturated areas using measured water table by piezometers and more qualitative assessments of the state of the moisture at soil surface or immediately under it to provide information that can usefully condition model predictions. Vegetation patterns can also provide useful indicators of runoff source areas, but integrated over much longer periods of time. In this way, it might be more likely that models will get the right predictions for the right reasons.
  
  KEY WORDS: Mapping variable source areas; Boot method; Piezometers; Vegetation mapping.
  
  Address:
  - Alena Kulasova, T. G. Masaryk Water Research Institute, Podbabska 30/2582, Prague, Czech Republic.
  - Keith J. Beven, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom.
  - Sarka D. Blazkova, T. G. Masaryk Water Research Institute, Podbabska 30/2582, Prague, Czech Republic. (Corresponding author. Tel.: Fax.: Email: Sarka_Blazkova@vuv.cz)
  - Daniela Rezacova, Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Bocni Str. II/1401, 141 31, Prague, Czech Republic.
  - Jiri Cajthaml, Czech Technical University in Prague, Faculty of Civil Engineering, Thakurova 7, 166 29, Prague, Czech Republic.