J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 1 - 6, doi: 10.2478/johh-2014-0001
Scientific Paper, English

Nadezhda Nadezhdina, Josef Urban, Jan Čermák, Valeriy Nadezhdin, Petr Kantor: Comparative study of long-term water uptake of Norway spruce and Douglas-fir in Moravian upland Douglas-fir in Moravian upland

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• Long-term water uptake of Douglas-fir and Norway spruce trees, growing in condition of Moravian upland, was studied with aim of comparing sap flow in small roots with flow in stems. Sap flow was measured by the heat field deformation method using multi-point sensors for stems and single-point sensors for roots. Differences between species were found in relationships between sap flow in tree stems and water uptake by roots, suggesting that Douglas-fir is able to take water from deeper soil more efficiently than spruce. This allows Douglas-fir to transpire more water especially during drought and grow faster than spruce. These biological features should be taken into account for future forest species compositions because they may have impact on both, forestry and hydrology.
  
  KEY WORDS: Sap flow; Shallow roots; Deep roots; Heat field deformation; Soil water potential.
  
  Address:
  - Nadezhda Nadezhdina, Mendel University of Agriculture and Forestry, Faculty of Forestry and Wood Technology, Zemědělská 3, 613 00 Brno. (Corresponding author. Tel.:+42 54513 4181 Fax.: Email: nadezdan@mendelu.cz)
  - Josef Urban, Mendel University of Agriculture and Forestry, Faculty of Forestry and Wood Technology, Zemědělská 3, 613 00 Brno.
  - Jan Čermák, Mendel University of Agriculture and Forestry, Faculty of Forestry and Wood Technology, Zemědělská 3, 613 00 Brno.
  - Valeriy Nadezhdin, Mendel University of Agriculture and Forestry, Faculty of Forestry and Wood Technology, Zemědělská 3, 613 00 Brno.
  - Petr Kantor, Mendel University of Agriculture and Forestry, Faculty of Forestry and Wood Technology, Zemědělská 3, 613 00 Brno.

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 7 - 15, doi: 10.2478/johh-2014-0008
Scientific Paper, English

Mohammad Nakhaei, Jiří Šimůnek: Parameter estimation of soil hydraulic and thermal property functions for unsaturated porous media using the HYDRUS-2D code

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• Knowledge of soil hydraulic and thermal properties is essential for studies involving the combined effects of soil temperature and water input on water flow and redistribution processes under field conditions. The objective of this study was to estimate the parameters characterizing these properties from a transient water flow and heat transport field experiment. Real-time sensors built by the authors were used to monitor soil temperatures at depths of 40, 80, 120, and 160 cm during a 10-hour long ring infiltration experiment. Water temperatures and cumulative infiltration from a single infiltration ring were monitored simultaneously. The soil hydraulic parameters and soil thermal conductivity parameters (coefficients b1, b2, and b3 in the thermal conductivity function) were estimated from cumulative infiltration and temperature measurements by inversely solving a two-dimensional water flow and heat transport using HYDRUS-2D. Three scenarios with a different, sequentially decreasing number of optimized parameters were considered. In scenario 1, seven parameters were included in the inverse problem. The results indicated that this scenario does not provide a unique solution. In scenario 2, six parameters were included in the inverse problem. The results showed that this scenario also results in a non-unique solution. Only scenario 3, in which five parameters were included in the inverse problem, provided a unique solution. The simulated soil temperatures and cumulative infiltration during the ring infiltration experiment compared reasonably well with their corresponding observed values.
  
  KEY WORDS: Infiltration; Heat transport; Parameter Estimation; Richards’ equation; HYDRUS-2D.
  
  Address:
  - Mohammad Nakhaei, Faculty of Geological Sciences, Kharazmi University, No.49, Mofateh Ave., Tehran, Iran.
  - Jiří Šimůnek, Department of Environmental Sciences, University of California, Riverside, USA. (Corresponding author. Tel.:+1-951-827-7854 Fax.: Email: Jiri.Simunek@ucr.edu)

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 16 - 23, doi: 10.2478/johh-2014-0004
Scientific Paper, English

János Józsa: On the internal boundary layer related wind stress curl and its role in generat-ing shallow lake circulations

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• The paper demonstrates that the wind stress curl as an external vorticity source plays an important role in shaping large scale shallow lake circulations. The analysis of purpose-oriented simultaneous wind and current measure-ments data from the Hungarian part of Lake Neusiedl reasonably fits well the internal boundary layer development theory over the lake surface. A 2-D vorticity formulation of wind-induced flows is used to demonstrate mathematically the IBL-related large scale circulation generation mechanism well reflected in the measured data. Further validation of the findings is carried out by means of simple 2-D numerical flow modelling, in which details on the flow pattern besides the measurement sites could be also revealed. Wind-induced lake circulations linked to IBL development shows a novelty to be implemented in up-to-date numerical flow models.
  
  KEY WORDS: Wind-induced flow; Internal boundary layer; Wind stress curl; Shallow lakes; Lake Neusiedl.
  
  Address:
  - János Józsa, Budapest University of Technology and Economics, Department of Hydraulic and Water Resources Engineering, also MTA-BME Water Management Research Group, Műegyetem rkp 3, H-1111 Budapest, Hungary (Corresponding author. Tel.: Fax.: Email: jozsa@vit.bme.hu)

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 24 - 32, doi: 10.2478/johh-2014-0011
Scientific Paper, English

Elena Szolgayová, Josef Arlt, Günter Blöschl, Ján Szolgay: Wavelet based deseasonalization for modelling and forecasting of daily discharge series considering long range dependence

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• Short term streamflow forecasting is important for operational control and risk management in hydrology. Despite a wide range of models available, the impact of long range dependence is often neglected when considering short term forecasting. In this paper, the forecasting performance of a new model combining a long range dependent autoregressive fractionally integrated moving average (ARFIMA) model with a wavelet transform used as a method of deseasonalization is examined. It is analysed, whether applying wavelets in order to model the seasonal component in a hydrological time series, is an alternative to moving average deseasonalization in combination with an ARFIMA model. The one-to-ten-steps-ahead forecasting performance of this model is compared with two other models, an ARFIMA model with moving average deseasonalization, and a multiresolution wavelet based model. All models are applied to a time series of mean daily discharge exhibiting long range dependence. For one and two day forecasting horizons, the combined wavelet – ARFIMA approach shows a similar performance as the other models tested. However, for longer forecasting horizons, the wavelet deseasonalization - ARFIMA combination outperforms the other two models. The results show that the wavelets provide an attractive alternative to the moving average deseasonalization.
  
  KEY WORDS: Daily streamflow; Wavelets; ARFIMA; Deseasonalization; Long range dependence; Forecasting.
  
  Address:
  - Elena Szolgayová, The Centre for Water Resource Systems, Vienna Universtity of Technology, Karlsplatz 13, 1040, Vienna, Austria. (Corresponding author. Tel.: Fax.: Email: szolgayova@waterresources.at)
  - Josef Arlt, University of Economics, Faculty of Informatics and Statistics, nám. W. Churchilla 4, 130 67, Prague, Czech Republic.
  - Günter Blöschl, Institute of Hydraulic Engineering and Water Resources Management, Vienna University of Technology, Karlsplatz 13, 1040, Vienna, Austria.
  - Ján Szolgay, Slovak University of Technology, Radlinského 11, 813 68, Bratislava, Slovakia.

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 33 - 42, doi: 10.2478/johh-2014-0005
Scientific Paper, English

Fabrizio Ungaro, Costanza Calzolari, Alberto Pistocchi, Francesco Malucelli: Modelling the impact of increasing soil sealing on runoff coefficients at re-gional scale: a hydropedological approach

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• Soil sealing is the permanent covering of the land surface by buildings, infrastructures or any impermeable ar-tificial material. Beside the loss of fertile soils with a direct impact on food security, soil sealing modifies the hydrological cycle. This can cause an increased flooding risk, due to urban development in potential risk areas and to the increased volumes of runoff. This work estimates the increase of runoff due to sealing following urbanization and land take in the plain of Emilia Romagna (Italy), using the Green and Ampt infiltration model for two rainfall return periods (20 and 200 years) in two different years, 1976 and 2008. To this goal a hydropedological approach was adopted in order to characterize soil hydraulic properties via locally calibrated pedotransfer functions (PTF). PTF inputs were estimated via sequential Gaussian simulations coupled with a simple kriging with varying local means, taking into account soil type and dominant land use. Results show that in the study area an average increment of 8.4% in sealed areas due to urbanization and sprawl induces an average increment in surface runoff equal to 3.5 and 2.7% respectively for 20 and 200-years return periods, with a maximum > 20% for highly sealed coast areas.
  
  KEY WORDS: Land Use change; Soil functional groups; Urbanization; Runoff; Emilia-Romagna.
  
  Address:
  - Fabrizio Ungaro, CNR IBIMET - Via Madonna del Piano 10. I-50019 Sesto F.no (FI), Italy. (Corresponding author. Tel.:+39 055 5226557 Fax.: +39 055 5226550 Email: fabrizio.ungaro@cnr.it)
  - Costanza Calzolari, Leibniz Centre for Agricultural Landscape Research, Institute of Socio-Economics, Müncheberg, Germany.
  - Alberto Pistocchi, GECOsistema srl - Botengasse, 27 I-39050 Jenesien (BZ), Regione Emilia Romagna - Autorita dei bacini regionali romagnoli, via Biondini, 1 I-47100 Forli (FC), Italy.
  - Francesco Malucelli, Regione Emilia Romagna - Servizio Geologico, Sismico e dei Suoli, Viale A. Moro, Bologna (BO), Italy.

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 43 - 54, doi: 10.2478/johh-2014-0007
Scientific Paper, English

Jana Kaiglová, Jakub Langhammer: Analysis of efficiency of pollution reduction measures in rural basin using MIKE Basin model. Case study: Olšava River Basin

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• This paper presents the results of testing the applicability of the MIKE Basin model for simulating the efficiency of scenarios for reducing water pollution. The model has been tested on the Olšava River Basin (520 km2) which is a typical rural region with a heterogeneous mix of pollution sources with variable topography and land use. The study proved that the model can be calibrated successfully using even the limited amount of data typically available in rural basins. The scenarios of pollution reduction were based on implementation and intensification of municipal wastewater treatment and conversion of arable land on fields under the risk of soil erosion to permanent grassland. The application of simulation results of these scenarios with proposed measures proved decreasing concentrations in downstream monitoring stations. Due to the practical applicability of proposed measures, these could lead to fulfilment of the water pollution limits required by the Czech and EU legislation. However, there are factors of uncertainty that are discussed that may delay or limit the effect of adopted measures in small rural basins.
  
  KEY WORDS: Water quality; Modelling; Rural basins; MIKE Basin; Non-point pollution; Land use.
  
  Address:
  - Jana Kaiglová, Charles University in Prague, Faculty of Science, Albertov 6, Prague 2, 128 43
  - Jakub Langhammer, harles University in Prague, Faculty of Science, Albertov 6, Prague 2, 128 43 (Corresponding author. Tel.: Fax.: Email: jakub.langhammer@natur.cuni.cz)

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 55 - 59, doi: 10.2478/johh-2014-0009
Scientific Paper, English

Ivan Nesmerak, Sarka D. Blazkova: Analysis of the time series of waste water quality at the inflow of the wastewater treatment plant and transfer functions

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• Time series of the daily total precipitation, daily wastewater discharges and daily concentrations and pollution loads of BOD5, COD, SS, N-NH4, Ntot and Ptot were analyzed at the inflow to the wastewater treatment plant (WWTP) for a larger city in 2004–2009 (WWTP is loaded by pollution from 435,000 equivalent inhabitants). The time series of the outflow from a WWTP was also available for 2007. The time series of daily total precipitation, daily wastewater discharges, concentrations and pollution loads at the inflow and outflow from the WWTP were standardized year by year to exclude a long-term trend, and periodic components with a period of 7 days and 365 days (and potentially also 186.5 days) were excluded from the standardized series. However, these two operations eliminated only a small part of the variance; there was a substantial reduction in the variance only for ammonium nitrogen and total nitrogen at the inflow and outflow from a WWTP. The relationship between the inflow into a WWTP and the outflow form a WWTP for the concentrations and pollution loads was described by simple transfer functions (SISO models) and more complicated transfer functions (MISO models). A simple transfer function (SISO model) was employed to describe the relationship between the daily total precipitation and the wastewater discharge.
  
  KEY WORDS: Analysis of time series; Wastewater treatment plant; Inflow and outflow; Concentrations and pollution loads; Transfer functions.
  
  Address:
  - Ivan Nesmerak, Prague
  - Sarka D. Blazkova, T. G. Masaryk Water Research Institute, Prague (Corresponding author. Tel.:+420 724 602 956 Fax.: Email: sarka_blazkova@vuv.cz)

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 60 - 74, doi: 10.2478/johh-2014-0010
Scientific Paper, English

Om Prakash, K. P. Sudheer, K. Srinivasan: Improved higher lead time river flow forecasts using sequential neural network with error updating

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• This paper presents a novel framework to use artificial neural network (ANN) for accurate forecasting of river flows at higher lead times. The proposed model, termed as sequential ANN (SANN), is based on the heuristic that a mechanism that provides an accurate representation of physical condition of the basin at the time of forecast, in terms of input information to ANNs at higher lead time, helps improve the forecast accuracy. In SANN, a series of ANNs are connected sequentially to extend the lead time of forecast, each of them taking a forecast value from an immediate preceding network as input. The output of each network is modified by adding an expected value of error so that the residual variance of the forecast series is minimized. The applicability of SANN in hydrological forecasting is illustrated through three case examples: a hypothetical time series, daily river flow forecasting of Kentucky River, USA and hourly river flow forecasting of Kolar River, India. The results demonstrate that SANN is capable of providing accurate forecasts up to 8 steps ahead. A very close fit (>94% efficiency) was obtained between computed and observed flows up to 1 hour in advance for all the cases, and the deterioration in fit was not significant as the forecast lead time increased (92% at 8 steps ahead). The results show that SANN performs much better than traditional ANN models in extending the forecast lead time, suggesting that it can be effectively employed in developing flood management measures.
  
  KEY WORDS: River flow forecasting; Forecast lead time; Error updating; Artificial neural network; Genetic algorithm.
  
  Address:
  - Om Prakash, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai – 600036, India.
  - K. P. Sudheer, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai – 600036, India. (Corresponding author. Tel.: Fax.: Email: sudheer@iitm.ac.in)
  - K. Srinivasan, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai – 600036, India.

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 75 - 81, doi: 10.2478/johh-2014-0003
Scientific Paper, English

Mir-Jafar-Sadegh Safari, Mirali Mohammadi, Golezar Gilanizadehdizaj: On the effect of cross sectional shape on incipient motion and deposition of sediments in fixed bed channels

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• The condition of incipient motion and deposition are of the essential issues for the study of sediment transport. This phenomenon is of great importance to hydraulic engineers for designing sewer, drainage as well as other rigid boundary channels. This is a study carried out with the objectives of describing the effect of cross-sectional shape on incipient motion and deposition of particles in rigid boundary channels. In this research work, the experimental data given by Loveless (1992) and Mohammadi (2005) are used. On the basis of the critical velocity approach, a new incipient motion equation for a V-shaped bottom channel and incipient deposition of sediment particles equations for rigid boundary channels having circular, rectangular, and U-shaped cross sections are obtained. New equations were compared to the other incipient motion equations. The result shows that the cross-sectional shape is an important factor for defining the minimum velocity for no-deposit particles. This study also distinguishes incipient motion of particles from incipient deposition for particles. The results may be useful for designing fixed bed channels with a limited deposition condition.
  
  KEY WORDS: Incipient motion; Incipient deposition; Cross-sectional shape; Rigid boundary channel; Sediment particles; Critical velocity.
  
  Address:
  - Mir-Jafar-Sadegh Safari, Faculty of Civil Eng., Istanbul Technical University, Istanbul, Turkey. (Corresponding author. Tel.: Fax.: Email: safari@itu.edu.tr)
  - Mirali Mohammadi, Dept. of Civil Eng., Faculty of Eng., Urmia University, Urmia, Iran.
  - Golezar Gilanizadehdizaj, Dept. of Nano Science and Nano Eng., Istanbul Technical University, Istanbul, Turkey.

J. Hydrol. Hydromech., Vol. 62, No. 1, 2014, p. 82 - 88, doi: 10.2478/johh-2014-0006
Scientific Paper, English

Jianhua Wu, Hui Qian, Peiyue Li, Yanxun Song: A system-theory-based model for monthly river runoff forecasting: model cali-bration and optimization

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• River runoff is not only a crucial part of the global water cycle, but it is also an important source for hydropower and an essential element of water balance. This study presents a system-theory-based model for river runoff fore-casting taking the Hailiutu River as a case study. The forecasting model, designed for the Hailiutu watershed, was calibrated and verified by long-term precipitation observation data and groundwater exploitation data from the study area. Additionally, frequency analysis, taken as an optimization technique, was applied to improve prediction accuracy. Following model optimization, the overall relative prediction errors are below 10%. The system-theory-based prediction model is applicable to river runoff forecasting, and following optimization by frequency analysis, the prediction error is acceptable.
  
  KEY WORDS: System theory; River runoff; Weight function; Frequency analysis; Uncertainty.
  
  Address:
  - Jianhua Wu, School of Environmental Science and Engineering, Chang’an University, No. 126 Yanta Road, Xi’an, 710054, Shaanxi, China. (Corresponding author. Tel.: Fax.: Email: wjh2005xy@126.com)
  - Hui Qian, School of Environmental Science and Engineering, Chang’an University, No. 126 Yanta Road, Xi’an, 710054, Shaanxi, China. Emails: wjh2005xy@126.com
  - Peiyue Li, School of Environmental Science and Engineering, Chang’an University, No. 126 Yanta Road, Xi’an, 710054, Shaanxi, China.
  - Yanxun Song, College of Geology Engineering and Geomatics, Chang'an University, No. 126 Yanta Road, Xi’an, 710054, Shaanxi, China.