Forthcoming articles


International Journal of Hydrology Science and Technology


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International Journal of Hydrology Science and Technology (48 papers in press)


Regular Issues


  • Comparison of solutions of Saint-Venant equations by characteristics and finite difference methods for unsteady flow analysing in open channel   Order a copy of this article
    by Kaveh Ostad-Ali-Askari, Mohammad Shayannejad, Saeid Eslamian, Bahareh Navabpour 
    Abstract: The unsteady flow can be analyzed by Saint-Venant equations. These equations can be solved by characteristics and finite difference methods. The Saint-Venant equations are changed into four complete differential equations in characteristics method and these equation are solved by drawing two characteristics lines. The Saint-Venant equations are changed into a set non-linear equations and are solved using Preissman scheme in finite difference method. This set equation are changed into linear equation using Newton-Rafson method and can be solved using Sparce method. In this research, the results of the two method were compared and this was shown that 1) these two methods can draw the surface profiles and flow hydrograph as well, 2) the finite difference method is more accurate than that one, 3) the mesh size in finite difference method can be larger than that one, and 4) the difference between two methods are increased by increasing the time and distance.
    Keywords: flood routing; dynamic wave; characteristics lines; finite difference; Saint-Venant equations; characteristics method ; Newton-Rafson method; Sparce method.

  • Evaluation of some probability distribution functions for derivation of unit hydrograph in the Bar Watershed, Iran   Order a copy of this article
    by Seyed Amir Naghibi, Mehdi Vafakhah, Alireza Moghaddam Nia, Saeid Eslamian 
    Abstract: Considering the ever increasing financial damages of floods and the need to manage the surface water, the use of new and more sufficient methods seems to be necessary. Therefore, the present study aims to investigate capability of the Gamma, Beta, Chi-square, and Weibull probability distribution functions (PDFs) for flood hydrograph derivation. The present study was conducted in the Bar watershed, Iran using 14 suitable rainfall-runoff events. After base- flow separation and direct runoff determination, the 3-hour unit hydrograph of the watershed was computed to determine the coefficients and parameters of the mentioned PDFs. Finally, Nash-Sutcliffe (NS), relative error (RE), and root mean square error (RMSE) indices were used for evaluation. According to the results, Gamma, Chi-Square, and Weibull PDFs had satisfying results for predicting the peak flow with RE values of 11.87%, 25.34% and 37.67% respectively. In the case of time to peak, Gamma, Chi-Square and Beta PDFs showed acceptable results with RE values of 26.66%, 39.17%, and 34.17 % respectively. Totally, considering the high importance of peak discharge and time to peak in flood control projects, Gamma PDF is recommended to be used in flood control projects.
    Keywords: Probability distribution function (PDF), Flood hydrograph, Time to peak, Peak discharge, Iran

  • The Performance of Fuzzy Regression Method for Estimating of Reference Evapotranspiration under Controlled Environment   Order a copy of this article
    by Mohammad Javad Amiri, Jahangir Abedi-Koupai, Saeid Eslamian 
    Abstract: With the objective of evaluating the performance of Fuzzy regression method for estimating the reference evapotranspiration in greenhouse, a lysimeter study was conducted to determine the evapotranspiration (ET) rates for grass crop. Daily outputs from model have been tested against reference evapotranspiration data computed by the lysimeter to assess the accuracy of the model. The estimated ETо values from a fuzzy regression model using five input parameters, including maximum and minimum temperature, mean relative humidity, wind speed and solar radiation were obtained with RMSE=0.68 mm/day, R2 =0.98. The accuracy of fuzzy 1 was the best but the accuracy of the Fuzzy 3 was the worse for estimating daily evapotranspiration. The RMSE values of fuzzy 1, fuzzy 2, Fuzzy 3 were 0.68, 0.99 and 1.307, respectively. Thus, Fuzzy 1 approaches work well for the data set used in greenhouse condition.
    Keywords: Evapotranspiration, Fuzzy regression, Lysimeter, Meteorological variable

  • Suspended sediment estimation using regression and artificial neural network models: Kebir watershed, northeast of Algeria, North Africa   Order a copy of this article
    by Amina Amamra, Kamel Khanchoul, Saeid Eslamian, Soraya Hadj Zobir 
    Abstract: The focus of this ‎research was to identify ‎potential equivalences ‎between ‎artificial ‎neural ‎networks and statistical ‎regression ‎and to verify these equivalences when ‎applied ‎to ‎modelling ‎sediment loads in the Kebir ‎river.‎ ‎ The use of ‎feed-forward backpropagation neural ‎networks such as MLP and LM were studied by ‎applying relationship‎ stream flow-‎sediment discharge ‎data and geomorphology watershed parameters. Daily based water and sediment discharge were used as inputs for sediment rating curve and ANNs.‎ In the present study the models were adopted by changing numbers of neuron in hidden layers and epoch. Results have shown that the ANN models were superior in reproducing sediment discharge compared to SRC. The findings further have suggested that LM could provide the most accurate estimates of sediment discharge, (R
    Keywords: Sediment discharge; geomorphology; Neural network; sediment rating curve; Kebir river.

  • Evaluation of Clark IUH in Rainfall-Runoff Modeling (Case Study: Amameh Basin)   Order a copy of this article
    by Meysam Salarijazi, Mohammad Abdolhosseini, Khalil Ghorbani, Saeid Eslamian, Iman Ahmadianfar 
    Abstract: The application of Clark IUH in Amameh basin, Iran is investigated in this study. Six recorded rainfall-runoff events were selected. Calibration results showed great changes in the calibrated parameters, percentage error in peaks and volumes (PEP and PEV), and the model efficiency (EFF) while percentage error in time to peak (PTEP) had always low values. Furthermore, the simulations of falling limbs of runoff hydrographs were better than rising limbs. Validation results indicated that time to peaks, runoff volumes, and falling limbs of runoff hydrographs were much better predicted than peak discharges, rising limbs, and total shapes of runoff hydrograph. One way sensitivity analysis revealed that the storage coefficient was more sensitive than time of concentration and EFF, PEP, PETP, and PEV had highest to lowest sensitivity. It can be concluded that the estimation of time to peak and runoff volume had higher performance than runoff hydrograph shape and peak discharge.
    Keywords: Clark IUH, Rainfall-Runoff Model, Sensitivity Analysis, Model Efficiency.

  • Determination of the height of vertical filter in heterogeneous earth dams with vertical clay core   Order a copy of this article
    by Mohammad Shayannejad, Saeid Salehi-Hafshejani, Hossein Samadi Boroujeni, Ali-Reza Zarraty, Bahareh Soltani, Kaveh Ostad-Ali-Askari 
    Abstract: In order to determine the height of the filter in heterogeneousearthdam, three embankment models were provided in a flume laboratory, with the length of 4.2 m at the base of dam, the width of 60 cm and the height of 1 m and bodyslope1H: 2V. For embankment of model,two types of fineand coarsegrained soils were used. The texture of the soil was made using hydrometer method. In the first model,the fine-grained and coarse-grained soils were used in downstream and upstream of the dam crest respectively. In Models2and3 with cutting fine grained soil from the toe of the dam to the dam crest,vertical clay core was replaced.Index of a / L (athickness of clay core and L is the length of base dam) was 1.7 and 1.10 in the second and third models respectively.Seepage experiments in 3 water height of 80and55and30 were performed.The phreatic surface was determined using wells and 30 embedded Piezometer in the models. Then rate of falling head due to clay core was measured and it compared with software PLAXIS V8.5 results.The clay core of height of filterwith safety factor 1.2 (Encounter Line Leak with 20% of the bottom filter)was introduced.The hydraulic conductivity of theclay were affected decline of water level.
    Keywords: Model of heterogeneous earth dam; HeightofFilter; thickness ofthe clay core; software PLAXIS V8.5.

  • Monitoring and prediction of drought by Marcov chain Model based on SPI and new index (SPEI) in Isfahan   Order a copy of this article
    by Saeid Eslamian, Mahsa Jahadi 
    Abstract: Abstract: Drought evaluation and associated prediction are essential for water resource management. Most of previous studies analyzed and predicted drought pattern in Isfahan based on the standardized precipitation index (SPI). Due to the high evapotranspiration in Isfahan, the SPI index which is based on precipitation alone may not be sufficient to monitor and estimate drought pattern. So it is vital to analyze and predict drought phenomenon at this region based on the new index (SPEI) that considers potential evapotranspiration in addition to the precipitation. Hence drought analysis is performed based on SPI and SPEI (standardized precipitation- evaporation index) in Isfahan. The results indicate that there is some difference between two indices. Finally SPEI and the Marcov Chain model are applied to predict the drought patterns in a 30 years period in the long term future. It is predicted that the percentage of aridity state will increase comparison with the past decade.
    Keywords: Keywords: Drought monitoring; Drought prediction; Isfahan; Iran; Markov chain model; SPEI index; SPI index.

  • Surfing Safe Waves: integration of water quality modeling in the evaluation of potential health risks   Order a copy of this article
    by Rita Marteleira, Pedro Bicudo, Antonio Guerreiro De Brito, Pedro Santos Coelho 
    Abstract: Surfing is becoming an important asset for local development, despite engaging water quality concerns is often limited to bathing season - thus, a tool for decision support is required to yearly forecast the water quality, in order to minimize health risks and support water management decisions. The QUAL2E model was used on a watershed, in Peniche, a coastal city in Portugal . This study area was chosen due to complaints related to the water quality by the local surfing community. Results returned a total coliform concentration of 1 500 MPN/100 mL, with pig farming effluents being the major contamination source. These results constitute an evidence that surfing here may represent a health risk as winter months are more favorable to wave sports. Therefore, it would be of the uttermost importance to improve monitoring and mitigate the potential health risk. This should include a more profound analysis of the contribution of diffuse sources and to extend the current bathing season monitoring scheme during winter times.
    Keywords: recreational waters; health hazards; simulation models; decision support systems; surfing; water quality.

  • Hydrological modeling of Upper Ebonyi watershed using the SWAT model   Order a copy of this article
    by Emeka Ndulue, Gloria Ezenne, Constantine Mbajiorgu, Vintus Ogwo, Kingsley Ogbu 
    Abstract: Effective planning and management of water resource requires the use of watershed models that can simulate streamflow, sediment and other hydrological components. Hydrologic models provide a framework for making appropriate decisions for sustainable management of land and water resources in the watershed. Hydrological models have become an indispensable tool for study of hydrological processes and its effectiveness is improved by the coupling of geographical Information System (GIS) interface to simulate various parameters attributed to a selected catchment and thus help watershed management in proper management. In this study, SWAT (Soil and Water Assessment Tool), a hydrological model is applied on the Upper Ebonyi watershed to simulate streamflow and sediment load. The results of sensitivity analysis, model calibration and model validation showed that the SWAT model reasonably simulate streamflow and sediment load in the watershed. Streamflow and sediment load simulations were calibrated against the daily flow using observed data in June to July 2013 and validated using observed data of September and October, 2014. The simulated daily flow fit the observed data for the calibrated period well, with R2, NSE and PBIAS values of 0.68, 0.58 and -0.871% respectively while the simulated daily sediment load fit the observed data with R2, NSE and PBIAS values of 0.53, 0.51 and 24.11% respectively. For the validation period, the values of R2, NSE and PBIAS values are 0.747, 0.719 and 5.16% for streamflow while , the values of R2, NSE and PBIAS values are 0.647, 0.606 and 4.92% for sediment load. This study is greatly limited by the poor availability of data and the unagauged nature of the basin. Hence, it demonstrates that the SWAT model is an effective tool for watershed and water resources management especially for ungauged basin.
    Keywords: Hydrological modeling; SWAT; Upper Ebonyi watershed.

  • Fissure structure analysis to unravel groundwater inflow problem in gold mining site of Pongkor area, West Java, Indonesia   Order a copy of this article
    by Sari Bahagiarti Kusumayudha 
    Abstract: Hydrogeology of Pongkor area, West Java, Indonesia is characterized by fractured aquifer system. The aquifer consists of volcanic rocks of Tertiary period, namely Cimapag formation. It is fractured with orientations axis of the fracture patterns are northwest southeast and northeast southwest. Pongkor area is drained by two main surface streams, called River Cikaniki and River Cimaja, normally flowing northward direction. In the study area, there is such a vein structure known as Vein Ciurug containing gold ore deposits. The vein is exploited by subsurface tunneling system. During expansion of the mining activity, some ramps were needed to be constructed. When a ramp at the altitude of +484 m above sea level was expanded, before reaching the vein, the drilling penetrated a saturated zone, causing groundwater inflow with a relatively massive rate. Further, static groundwater flow flooded the opening ramp down with water level of +499 m above sea level, resulted in disruption of mining activities atthe rampsunder the elevation 500 m above sea level. This study is to analyse the source of groundwater inflow and set a recommendation to solve the problem.
    Keywords: Fractured aquifer system. Surface flow. Tunnel inflow. Mining problem.

  • Determination of evapotranspiration for cotton in Alabama by the Penman method   Order a copy of this article
    by Mahbub Hasan, Aschalew Kassu, Srinivasa Rao Mentreddy 
    Abstract: Cotton irrigation is increasingly becoming a challenge because of climate change effects such as the variations in rainfall, temperature, and cloudiness during the growing season. Cotton crop characteristics, as well as the prevailing environmental conditions, are critical in determining cotton water use. An efficient method of scheduling irrigation to cotton crop is imperative for optimizing time and amount of water to apply for achieving cotton yield potential. In this article, a reliable approach to determine crop water requirement for cotton cultivation is proposed using the Penman method for Gadsden, Alabama, located in the southern part of the United States.
    Keywords: Evapotranspiration (ETc); Penman equation; reference crop coefficient (Kc); net radiation (Rn); energy balance.

  • Treatment of world's largest and extensively hydrocarbon polluted environment: experimental approach and feasibility analysis   Order a copy of this article
    by Yohannes Yihdego, Radwan A. Al-Weshah 
    Abstract: This paper investigated approaches to treat the polluted groundwater in selected aquifers in Kuwait, which is the most extensive and second to none in terrestrial world case history. The selected aquifers are susceptible to pollution by oil spills during the first Gulf War. Experimental sampling of polluted soils were analysed. Results showed that granulated activated carbon is very effective in removing petroleum hydrocarbons from contaminated water. A pump-and-treat remediation scheme has been suggested for the affected parts of the freshwater fields. The cost estimates indicated that a treatment process involving carbon adsorption to remove petroleum hydrocarbons, followed by reverse osmosis to remove salt was highly likely to be the most cost-effective treatment system. The current treatment design and parametric costing approach can be applied elsewhere for the role of bioremediation in the treatment of petroleum contaminated environment, hazardous effects of petroleum hydrocarbon and genetic engineering in bioremediation.
    Keywords: petroleum; hydrocarbon; pollution; contamination; remediation; hazardous.
    DOI: 10.1504/IJHST.2018.10006087
  • Solar Photocatalytic Detoxification Using Immobilized Titanium Oxide A Cost-effective Tertiary Treatment Method for Decentralized Wastewater Effluents   Order a copy of this article
    by Moahmmed Matouq 
    Abstract: To examine the capacity of using TiO2 (AEROXIDE P25/Evonic as a solar photo catalytic reaction to actual real wastewater effluent from a constructed decentralized treatment unit has investigated. Before conducting the experimental works the oxidation of potassium hydrogen phthalate (KHP) as a model compound, is investigated thoroughly as a model. KHP used here as a standard for both chemical oxygen demand (COD) and total organic carbon (TOC). The catalyst load, initial KHP concentration and pH are the variables studied in this research. The nano particle of TiO2 (P25) was immobilized by dip coating and heat treatment on borosilicate glass tubes in tubular reactor. The solar photocatalytic oxidation process was examined in continuous mode with different wastewater flow rates, initial KHP concentration and pH. Optimum conditions obtained for KHP oxidation applied for a typical secondary treated wastewater out of decentralized wastewater treatment unit located in a rural area nearby the campus. The results revealed that the optimum flow rate is 2.5 l/min in the tubular reactor. The removal efficiency of the organic compounds reduces as the initial concentration of KHP increases. The photocatalytic oxidation is dependent on pH and, it increases with the increasing of pH. Treatment of secondary treated wastewater results in about 50% removal of organic matter and 100% inactivation of E-Coli with no regrowth after 24h storage in dark was obtained.
    Keywords: wastewater treatment; Catalytic degradation; TiO2; P25/Evonic; photo catalytic ; water treatment KHP degradation; TiO2 Detoxification; solar radiation; TiO2kinetics.

  • Modeling hydraulics of flow-path cuts through dense vegetation in a northern Everglades wetland   Order a copy of this article
    by Kyle Douglas-Mankin, Donatto Surratt 
    Abstract: Flow-path cuts through dense marsh vegetation can dominate wetland hydraulics. The friction equation, including Mannings, provides simple, effective modeling of flow velocity, but this was the first study to apply the friction equation to wetland flow-cut hydraulics. Side-facing acoustic Doppler velocity and channel geomorphologic data were collected at seven locations on three shallow airboat flow-cuts and one deeper canoe trail in the Everglades. Data were fitted to the friction equation using friction (a), water depth (b), and water surface slope (c) parameters. Mannings form of the friction equation (b = 1.67, c = 0.5) was inappropriate to simulate shallow, low-gradient flow-cuts. The best overall statistical performance for describing flow-cut hydraulics was a = 3.18 x 10^7 m^ 0.72 d^-1, b = 1.28, c = 1.00 for airboat trails and a = 1.39 x 10^7 m^0.72 d^-1 for the canoe trail. Two applications are presented to demonstrate use of these models to quantify impacts of flow-cuts.
    Keywords: Acoustic Doppler velocity meter; friction equation; Manning’s equation; marsh vegetation; wetland hydraulics; wetland hydrology.

  • Influence of calibration data on hydrological model prediction   Order a copy of this article
    by Shailesh Kumar Singh, Jiaying Liang, Alejandro Chamorro 
    Abstract: The quality and information content of data has a great influence on the calibration and validation of hydrological models. A model calibrated with data from a given time period can perform well or poorly when evaluated on prediction time period. This depends on the information content and hydrological variability of the calibration data, in relation to the validation period data. The hypothesis for this study was that a priori predictability of the model performance can be made based on knowledge about the data used for calibration of the model. If the validation time period has similar hydrological variability to the calibration period where the model is expected to perform better and it is termed as the interpolation case, otherwise it is extrapolation, where a better performance cannot be expected. In this study a geometrical property of data was used to discriminate between the cases of interpolation or extrapolation. To see the geometry of the input data, a data depth function was used. A case of interpolation and extrapolation was defined based on the location of data in relation to the convex hull of the calibration data set. The results show that the data available for calibration has great influence on the prediction performance of the model. It was found that the relative residual is very high at extrapolation case as compare to the interpolation case. The methodology was demonstrated using WaSiM-ETH model in Rems (right tributary of the Neckar River in eastern Baden-W
    Keywords: Hydrological model; Interpolation; Extrapolation; Data depth function; WaSiM-ETH.

  • Urban water consumption in water-stressed areas of the developed world: An examination of multiple interrelated variables   Order a copy of this article
    by Alvaro-Francisco Morote, María Hernández, Saeid Eslamian 
    Abstract: The developed world has witnessed significant land changes since the second half of the twentieth century. These include a process of intensive urban development, which is also accompanied by the growth in the urban population and housing. One of the outcomes of this process has been an increase in the consumption of resources, including water. The aim of this paper is to identify and analyse the factors affecting water consumption and the areas studied in water-stressed regions of the developed world. A literature review of territorial studies examining the factors that affect urban water consumption in these areas was conducted methodologically. The results reveal that: a) a significant number of papers have been written on water consumption factors in areas where there is substantial urban growth; and b) North America and Australia, have been compared to the rest of the developed world (especially Southern Europe), recently (since 2000s) due to the expansion of the low-density urbanism in the last few years.
    Keywords: water; urban; factors; consumption; water-stressed areas; developed world.
    DOI: 10.1504/IJHST.2018.10007714
  • Changing climate and glacio-hydrology: A case study of Shaune Garang basin, Himachal Pradesh   Order a copy of this article
    by Shaktiman Singh, Rajesh Kumar, Anshuman Bhardwaj, Ramesh Kumar, Atar Singh 
    Abstract: The rise in temperature is already evident in Himalaya with rate of increase varying seasonally and spatially. Changes in precipitation are also evident with no clear trend. Several studies in different parts of Himalayas suggest that the glaciers are retreating in general with few exceptions as response to changes in temperature and precipitation. The stream flow in river basins in Indian Himalayan region (IHR) is already showing changes in studies undertaken in last few decades. Use of glacio-hydrological models gives opportunity to estimate stream flow in glaciated river basins and understand the changes. Present study deals with estimation of discharge in Shaune Garang Basin, Himachal Pradesh using a glacio-hydrological model based on degree day factors. The model was used to estimate long term average of melt season discharge (19852007) in the basin. The modelled discharge shows good correlation with measured discharge for simulation period except for first year of comparison.
    Keywords: climate change; snow melt; glacier melt; glacio-hydrological modelling; degree day factor.
    DOI: 10.1504/IJHST.2018.10010353
  • Spatio-Temporal prediction of water quality parameters of a reservoir using Genetic Programming and Least Square Support Vector Machine.   Order a copy of this article
    by Mrunalini Jadhav, Kanchan Khare, Arundhati Warke 
    Abstract: In water quality Spatio temporal modelling is used for classification or pattern recognition by using multivariate statistical techniques. Sometimes due to extreme environmental conditions or limited or insufficient water quality testing locations, it is difficult to find water quality parameters of previous time series. In the present study an attempt has been made to develop Spatio- temporal prediction model using Genetic Programming (GP) and Least Square Support vector Machines(LS-SVM). Water quality parameters such as, BOD (Biochemical Oxygen Demand), COD(Chemical Oxygen Demand), DO(Dissolved Oxygen), and P-total(Phosphorous) from Gangapur, Kadwa and NandurMadmeshwar reservoirs are used for the prediction of the same parameters respectively for the next time step of NandurMadmeshwar reservoir. Data from single sampling point station from July 2007 to Jan 2015 is used for the study, as input data being small and only from three locations, it is a great challenge for the prediction. Performance of models is assessed by COD (Coefficient of Determination), RMSE (Root Mean Square Error) and CC (Correlation Coefficient).Models are also evaluated by using Band error, to know the upper limits of the water quality parameters or the number of months for which the water quality standards has been violated.
    Keywords: Genetic Programming; Least square support vector machines; Water quality parameters; Coefficient of determination; Root mean square error; Correlation coefficient; Band error.

  • Efficacy of slope-adjusted curve number models with varying initial abstraction coefficient for runoff estimation   Order a copy of this article
    by Sangeeta Verma, Anju Singh, Surendra Kumar Mishra, Pushpendra Kumar Singh, Ravindra Kumar Verma 
    Abstract: The present study evaluated the efficacy of three slope adjusted CN2 models as well as original SCS-CN method using LISS-III and ASTER DEM data. The Performance of these models were also evaluated for four different values of initial abstraction coefficient (λ) i.e., 0.05, 0.1, 0.2 and 0.3 for the Kalu watershed in Maharashtra, India using R2 and RMSE. The results show that slope adjusted CN formulation given by the Sharpley and Williams (1990) (Model 2) for λ = 0.3 performed the best with lowest RMSE (10.88) and highest R2 (0.8757) in comparison to the other models. On the contrary, original SCS-CN model performed the worst. Results also show that watershed slope is an important factor affecting runoff generation and hence due consideration should be given to it in planning of soil and water conservation structures. This study also revealed that RS and GIS techniques are useful for estimating as SCS-CN model input data to predict runoff more accurately.
    Keywords: SCS-CN method; runoff; slope adjustment; initial abstraction coefficient; RS and GIS.

  • Relationship between precipitation and soil water chemistry in an intensively managed clayey soil environment in southwest England: A preliminary study   Order a copy of this article
    by Adebayo Eludoyin 
    Abstract: This study investigated the temporal characteristics of precipitation chemistry, and precipitation-soil water chemistry relationship at an intensively managed farm in the United Kingdom. Data investigated were the Environment Change Network (ECN) Terrestrial observation data for the Rothamsted Research Farm Platform at North Wyke in Devon. Results showed that temporal variability exists in the precipitation chemistry but did not show that either the soil or the precipitation was chemically impaired. Temporal variations in the precipitation chemistry were attributed to climatic effects and anthropogenic sources as informed by the trends and results of the comparison to the seawater ion ratio. Strong relationships that existed in the investigated chemical variables (except Cl- and PO43-) between the top (above 10 cm) and lower (below 10 cm) soil layers indicated significant mixing of the soil water at this profile. The study indicated significant precipitation-soil water chemistry in the clayey-rich area.
    Keywords: Precipitation; Soil chemistry; Runoff processes; Clayey-rich soils.

  • Modelling of hydrological processes in snowmelt-governed permafrost-free catchments of the Western Siberian Lowlands   Order a copy of this article
    by Jens Kiesel, Matthias Pfannerstill, Britta Schmalz, Vitaliy Khoroshavin, Artyom Sheludkov, Tatyana Veshkurseva, Nicola Fohrer 
    Abstract: To date, no examples of small- to meso-scale hydrological simulations exist in the southern part of the Western Siberian Lowlands, despite intensive agriculture and high vulnerability to climate change. We propose a first simulation approach in which we assess the importance of surface and groundwater processes on hydrological model performance. Therefore, we simulated three catchments, using four different model setups incorporating different landscape characteristics and processes. An objective calibration and comparison framework was applied to assess the different setups which reached very diverse performance: The setups where physically based surface retention is considered, showed slightly more realistic surface runoff driven peak flows and the setups with a more complex groundwater concept improved the depiction of surface runoff, the recession phase and the contributing baseflow significantly. The best performing, most complex setup was used to assess the prevailing hydrological processes of the lowland with its cold, continental climate in more detail.
    Keywords: groundwater; surface water retention; flow duration curve; hydrological process evaluation; SWAT3S.
    DOI: 10.1504/IJHST.2018.10007182
  • Potential Impacts of Climate Change on Precipitation Patterns over Iran (An Arid/Semi-Arid Climate)   Order a copy of this article
    by Jaber Rahimi, Ali Khalili 
    Abstract: In this study, two objectives were paramount. One is to assess the spatio-temporal patterns of precipitation in Iran and the other is to investigate the projected changes in these patterns for the period 20712100 as compared to 19652010. These were achieved by using monthly precipitation data from 256 rain gauge stations and the outputs of the HadCM3 global circulation model (under the A2 and B2 scenarios). The statistical (Delta Method) and dynamical (PRECIS) downscaling techniques were compared in terms of their results for projecting annual isohyets, annual march of monthly precipitation and the precipitation homogeneity. The results showed that, by HadCM3_Delta Method_A2, HadCM3_Delta Method_B2, HadCM3_PRECIS_A2 and HadCM3_PRECIS_B2 projections, the annual mean precipitation over the country (which is already 254 mm) would be 208.6, 187.1, 174.1 and 175.0 mm, respectively. Also, the corresponding values for the average of precipitation homogeneity index would change from 57% in the current conditions to 53, 54, 59 and 61 % in climate change conditions, respectively. Although temporal and spatial monthly precipitation was envisaged, there was no impressive impact of climate change on precipitation pattern, but it's effect on time of maximum precipitation was subtle.
    Keywords: Intra-Annual Precipitation Regimes; Climate Change; Downscaling; Iran.

  • A Simplification of the Einstein Equation for the Calculation of Suspended Sediment Transport in Rivers   Order a copy of this article
    by Hydar ALI, Thamer Mohammed, Badronnisa Yusuf, Azlan Aziz 
    Abstract: In this study, a simplified equation for estimating suspended sediment load is proposed, based on regression analysis and the concept presented by Einstein, Ackers and White, and Shields. Field data for 11 rivers located at different parts of the world were used for the calibration and validation of the proposed equation. The results show that the equation gives a good performance compared with Einsteins and Bagnolds equations when tested using field data for the Atchafalaya, Red, South American, Rio Grande and Al-Garraf Rivers. The minimum and maximum values of Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) between the output of the proposed equation and field records were 0.005 to 0.007 and 0.09 to 0.289, respectively. For the above rivers, graphical comparisons show that the predicted values of suspended sediment load had a range of D50<0.14 and 0.140.2 gave a good prediction compared with the measured sediment load. The main advantages of the proposed equation are that it is easy to apply and the results obtained from its application have reasonable accuracy.
    Keywords: Equation; Suspended Sediment; Natural Rivers; Validation; Testing.

  • ANFIS Based PCA to Predict the Longitudinal Dispersion Coefficient in Rivers   Order a copy of this article
    by Abbas Parsaie, Amir Hamzeh Haghiabi, Hazi Mohammad Azamathulla 
    Abstract: Study on the river water quality is the main part of environmental engineering. Longitudinal dispersion coefficient () is one of the main important parameters in the river water quality studies. The is proportional to the flow velocity, channel width, depth of flow, and shear velocity. The results of Principal component analysis (PCA) indicate that the width of the river, flow depth, and flow velocity are the most important parameters on the . In this paper with aim of the PCA results, the adaptive neuro fuzzy inference system (ANFIS) model was developed to predict the . The performance of developed ANFIS model based on PCA with error indices ( and RSME=0.055) is suitable to predict the . During the development of ANFIS model, five neurons to the width channel, four neurons to the flow depth, four neurons to the velocity and two neurons to the shear velocity were assigned. The hyperbolic tangent sigmoid (tansig) function was considered as membership function for the neurons.
    Keywords: River Mixing; Water Quality; River Pollution; ANFIS; PCA.

  • Reducing Water Shortage Crisis Through Rainwater Reuse: Lessons Learned from Ancient Toward Integrated Technology   Order a copy of this article
    by Saeid Okhravi, Saeid Eslamian, Nicolas R. Dalezios 
    Abstract: The quantity of freshwater available per person in the world has been proceeded to decrease due to a combination of factors, including population increase, water pollution, inadequate planning and management of transboundary water, and inefficient operation of water supply and distribution systems. There is a direct water source to cease increasing potential for water scarcity, crisis and associated conflicts around the world in the future called rainwater harvesting that is an ancient technique enjoying a revival in popularity due to the inherent quality of rainwater and interest in reducing consumption of treated water. Rainwater harvesting is included as an innovative site design strategy to minimize runoff based on LID practices. The present study on literature attempts to offer a comprehensive account of the above issues and also some important guidelines for advancing research in this direction. Assessments of past, present and future statuses of the worlds water are reviewed.
    Keywords: Climate change; LID; Rainwater harvesting; Stormwater management; Water crisis.

  • Cost-Effective Smart Irrigation Controller Using Automatic Weather Stations   Order a copy of this article
    by Hema Nagaraja 
    Abstract: Water has become increasingly scarce and valuable resource due to the increasing population and misuse of the same. Agriculture is the largest sector using scarce water resource with low efficiency and low-cost. Traditional irrigation methodology uses qualitative or feel approach to schedule irrigation which does not measure actual environmental condition. The quantitative approach requires additional setup for measuring climate condition for scheduling the irrigation. Low cost innovative water-saving technology is the need of the hour. The presented work proposes the cost-effective smart irrigation controller using automatic weather stations. The proposed smart controller makes real-time irrigation decision by gathering climatic data from nearby automatic weather stations. Automatic weather stations data are available on an hourly basis from Indian meteorological department. The primary challenge in designing irrigation controller is to acquire real-time data, to validate and to reconstruct the missing data. These problems are addressed in the presented paper. Evapotranspiration computed from nearby automatic weather stations are comparable with evapotranspiration provided by Indian agricultural research institute.
    Keywords: Smart Irrigation Controllers; Automatic Weather Station; Real-Time Climatic Data; Validation; Reconstruction.

  • An Introduction to the Hyperspace of Penman-Monteith Reference Evapotranspiration   Order a copy of this article
    by Naim Haie, Rui Pereira, Gaspar Machado, Shakib Shahidian 
    Abstract: Evapotranspiration is crucial and very relevant to hydrology, particularly under global warming and the growing water scarcity. The FAO Penman-Monteith is the highly used method to calculate the daily standardized reference evapotranspiration (ETo). It utilizes seven variables, mostly climatic, and produces a complex n-dimensional domain (or hyperspace). No study has presented the internal structure of this 8D space which forms the objective of the present work. To this end, a computer program called HyperET is developed to facilitate the advancement of two intertwined processes: creating windows into the hyperspace and understanding the resulting regions of the domain. The former gives 2D figures for partial analysis and the latter presents significant infeasible regions which are subspaces composed of ETo values outside its chosen minimum and maximum (or thresholds). HyperET is expensive computationally and presents an ETo domain that resembles Swiss holey cheese with three types of infeasible regions and emerging non-linearity.
    Keywords: Penman-Monteith evapotranspiration (ETo); hydrology; irrigation; water management and design; infeasible regions of ETo; climate change; water scarcity; hyperspace; HyperET; domain discretisation; n-dimensional analysis; sefficiency.
    DOI: 10.1504/IJHST.2018.10007892
  • Maximum Total Rainfall and Intensity by using Hershfield Isohyet Maps and Weiss Equation   Order a copy of this article
    by Mahbub Hasan, Aschalew Kassu, Srinivasa Rao Mentreddy 
    Abstract: Southern region of the United States does not show a regular or uniform pattern of rainfall. A study done by Hasan et al. in 2008 stated that there is an uncertainty in distribution of rainfall has never been a favorable water resource for crop production. Accurate information on total rainfall and rainfall intensity is necessary for calculating the amount of rainfall needed for crop water use, storage and for designing flood control and water conveyance structures. Models developed based on weather data can help forecast potential total rainfall, supplemental irrigation, water storage, and water losses. Total rainfall and intensity were calculated by linearizing method based on isohyet (lines of equal rainfall) maps developed by Hershfield (1963), and by using the Weiss equation (1962). The calculated values of the maximum total rainfall and intensity were 50.80 and 119.38 mm and 101.60 and 19.90 mm/h, respectively for 0.33 and 6.0-hour storm durations. These results showed a very good agreement with the actual data collected from the National Oceanic and Atmospheric Administration (NOAA) climate station in Gadsden, Alabama. Hence, this method of calculating the maximum rainfall and its intensity can be a valuable tool to determine rainwater harvesting, rainwater storage, irrigation scheduling and designing of flood control structures.
    Keywords: Total rainfall; Rainfall intensity; Rainfall duration; Linearization; Hershfield Isohyets; Weiss equation.

  • Hydrological study and suspended sediment transport in the MACTA: Mekerra watershed (NW Algerian)   Order a copy of this article
    by Saleh MOKADMI, El-Amine CHERIF 
    Abstract: The aim of this work is hydrological study and quantification of solid suspended transport in Mekerra basin whichi is located in the northwest of Algeria, in order to understand and explain the mechanisms of sediment, their causes and their consequences. The quantitative and qualitative analysis of the liquid flows and solid flows measured at this representative basin over a period from 1988-2009 (Station: Sidi Bel Abb
    Keywords: hydrological study; quantification of solid suspended transport; classes of evolution; sediment; Sidi Bel Abbes; Algeria.

  • A Bootstrap Regional Model for Assessing the Long-Term Impacts of Climate Change on River Discharge   Order a copy of this article
    by Chi-Yu Li, Shiu-Shin Lin, Yi-Fong Lin, Ping-Shiuan Kan 
    Abstract: Water resources in Taiwan come predominantly from rivers. Hence, it is important to understand the impact of future climate scenarios for policy-making. To investigate the impact of accelerating climate change on river flow in Taiwan, a Regional Flow Impact Model (RFIM) was developed. The RFIM is based on the Radial Basis Function Neural Network. It adapts the genetic algorithm for parameter optimisation, and the bootstrap method for quantifying uncertainties in the model and its results. The study area is the Taiwan Island, divided into four water resource management regions: North, Middle, South, and East. After the RFIMs were developed for different regions, various future weather scenarios predicted from global circulation models were applied. The results suggest that the average discharge increases at a higher rate in the Middle and the East, and the uncertainty of future discharge is higher in the Middle and the South of Taiwan Island.
    Keywords: climate change; genetic algorithm; neural network; regional river model; bootstrap.

    by Ifeanyichukwu Ezekwe, Chukwuma Oji 
    Abstract: This study was an attempt to decipher groundwater flow patterns and the factors that affect it in the Obagi Oil Fields of South-South Nigeria. In this study, head, position and geological data were obtained from 13 hand dug wells tapping the water table and the Sombreiro and the Orashi Rivers, while water quality data was generated through groundwater sampling and analysis using standard methods. This study discovered a hidden channel system, a reversed recharge system for the Sombreiro River system with serious local groundwater quality implications. Groundwater flow in the study area has components of regional, intermediate and local flow systems, while movement is controlled by topography; recharge; a groundwater channel system running NW-SE through the middle of the study area and a system of wetlands in the Omoku and Erema areas. These wetlands which are used as sinks are also major recharge areas for the groundwater system in the study area thereby posing public health dangers. Also the dumping of industrial and domestic wastes in the wetlands may be limiting the capacity of these wetlands as sinks and purification plants for the natural hydro-geopollution cycle.
    Keywords: Water Quality; Groundwater Channels; Groundwater controls; Tothian flow; Orashi; Sombreiro.

  • Dynamic parameter estimation for hydrological model   Order a copy of this article
    by Shailesh Kumar Singh 
    Abstract: Hydrological models are frequently used for forecasting, water management and decision making in watershed development. Due to simplification of complex natural processes in a hydrological model and the limited availability of observations, parameters of these models cannot be identified precisely during model calibration. Parameters of models are commonly assumed to be time independent even though some catchment properties are not stationary. The flexibility of hydrological models can be increased by introducing dynamic variation in the parameters of a hydrological model. In turn, this will improve the representation of natural processes. The purpose of this paper is to develop a methodology to investigate the dynamic nature of model parameter. A Robust Dynamic Parameter Estimation (RDPE) algorithm is developed which can be used for model diagnosis as well as for improving model predictions by allowing for parameter time dependence. After identification of the range of time varying parameters, a moving window approach and simulated annealing are used to optimize the parameters of the HBV (Hydrologiska Byrans Vattenavdelning) hydrological model for the each window size. The resulting time series of parameters are used for defining sensitive and insensitive periods in parameter time series and for understanding the reasons for parameter variation in time. To improve predictions a predictive parameter model is developed and applied using HBV model on meso-scale catchments in the Neckar basin in South-West Germany using HBV model. Finally, it is shown that the new methodology leads to more realistic confidence intervals for model simulations and model structure identification.
    Keywords: Time varying parameters; RDPE algorithm; HBV; Parameter estimation.

  • Contribution of the multivariate analysis and origin for groundwater quality of mixed aquifer in the Msila plain (Algeria)   Order a copy of this article
    by Mostefa Dougha, Mahmoud Hasbaia 
    Abstract: The change of climate and intensive exploitation of groundwater resources in the plain of Msila has influenced the hydrochemical functioning of the complex aquifer. This resulted in a decrease in the piezometric level of groundwater. The multivariate statistical techniques were used to determine the main factors and regrouping parameters/wells and to understand the origin of groundwater chemistry. Multivariate analysis (principal component analysis and cluster analysis) was performed to identify a common source for sampling data of a semi-arid aquifer. Physicochemical analyses were conducted on the waters of 17 wells. The chemical water classification shows the dominance of a chlorinated calcium and magnesium sulphate type facies, which has a very remarkable tendency towards the salinisation. Cluster analysis based on major parameters contents defined four main chemical water groups with increased water-rock interaction. Some parameters presented the highest concentrations of the total of dissolved salts provoking a poor quality of water.
    Keywords: multivariate analysis; PCA technique; HCA technique; piper; hydrochemical facies; water quality; origin of groundwater; salinity; mixed aquifer; M’sila plain.

  • Optimal Control Applied to an Irrigation Planning Problem : a real case study in Portugal   Order a copy of this article
    by Sofia O. Lopes, Rui M.S. Pereira, Paulo A. Pereira, Amélia C. Caldeira, Victor Francisco Fonte 
    Abstract: In this paper, a daily plan model to the irrigation of a crop field using optimal control was developed. This daily plan model have in consideration: weather data (temperatures, rainfall, wind speed), the type of crop, the location, humidity in the soil at the initial time, the type of soil and the type of irrigation. The aim is to minimise the water used in the irrigation systems ensuring that the field crop is kept in a good state of preservation. MATLAB was used to develop our mathematical model and obtain its output. Its results were compared with experimental ones obtained from a real farm field of grass in Portugal. This comparison not only allowed us to validate our model, but also allowed us to conclude that, using optimal control considerable savings in water resources, while keeping the crop safe are obtained. Some real test cases were simulated and the comparison between the optimised water to be used by the irrigation system (calculated by software) and the real amount of water used in irrigation site (on-off control system for irrigation) produced water savings above 10%.
    Keywords: optimal control; irrigation systems; real data; water resources; Portugal.
    DOI: 10.1504/IJHST.2019.10009095
    by Marzieh Momeni, Zahra Zakeri, Sina Zahedi, Vahid Razavi 
    Abstract: According to a numerous environmental sustainability indicators, Iran is considered to be in an undesirable situation. Meanwhile "critical water crisis" is one of the most fundamental problems that decision and policy makers are facing. Thus, analyzing and coming up with solutions for the current water crisis is of outmost importance. The current study intends to focus on East and West Azarbaijan, in which Lake Urmia basin covers main part of this area. According to the sustainable development index of The United Nations Educational, Scientific and Cultural Organization (UNESCO) for water resources, this basin is exposed to extremely high risks of drought (High Risk Category> 40 %). Statistics indicate that the total amount of water consumption for selected agricultural products, in these provinces, is approximately 9.52 Billion Cubic Meters (BCM). In other words, agriculture sector consumes almost 91.8 % of allocated water in this area. For a better understanding of the current situation, this research focused on the water consumption in agriculture sector. Furthermore, by using partial equilibrium method, real virtual water content, calculated by amount of allocated water, was compared to that calculated based on water requirement of selected products. The results show that for production of one unit per kilogram, real water consumption is more than water requirement indicating that averaged value of water efficiency for producing most of the agricultural products in East/West Azarbaijan is almost 21%. Due to the water crisis, appropriate policies should be made to improve efficiency of water consumption in this area.
    Keywords: Real Virtual Water Content; Water Consumption Efficiency; Partial Equilibrium; East Azarbaijan; West Azarbaijan.

  • An assessment of Water Resources at Halayib and Shelatine Sub regions, Southeastern Desert, Egypt, Using Conventional and Isotopic Approaches   Order a copy of this article
    by Samir Al-Gamal 
    Abstract: Surface water resources are expressed as potential surface runoff of ten watersheds in Halayib and Shelatine sub regions. Hydrologic response of the studied watersheds subjected to single storm event is tested. Base flow source areas and major recharge areas were delineated by infiltration using conventional infiltrometer and the water isotopes of O-18 and H-2. Aerial and linear aspects of each watershed were defined and due to paucity of runoff data, potential runoff was determined according to Snyders equation (1938). Groundwater resources are represented by two main aquifers; those pertaining to wadi fill and alluvial deposits of Quaternary aquifers resting unconformably over fluviatile sandstone of Um-Barmil Formation of Upper Cretaceous age. The Quaternary aquifer is receiving direct recharge from the present day precipitation as a consequence of infiltration from runoff water; particularly for soil of high infiltration capacity (7 mm/h).This represents the first pole of water while paleowater derived from the fluviatile sandstones of the tectonically dissected Um-Barmil Formation of Upper Cretaceous age represents the 2nd pole of water. Stable isotopes of O-18 and H-2 have proven the hydraulic connection between those two main aquifers. The foregoing situation has resulted in mixing of the two water types. The δ18O and δ2H values suggest a local meteoric line (whose slope of 5), characterizing low intensity, short duration rainfall, which partially were being evaporated during their precipitation.
    Keywords: groundwater; surface water; infiltration;environmental isotopes; d-excess; aquifer;watershed.

  • Climate modeling using ANN   Order a copy of this article
    by Mehnaza Akhter, Manzoor Ahanger 
    Abstract: In the present study artificial neural network (ANN) model was applied to monthly temperature and precipitation data for base time (19792009) at four different metrological stations viz.Srinagar, Pahalgam, Qazigund and Gulmarg of river Jhelum basin in the State of Jammu & Kashmir, India and the future average annual temperature and precipitation predicted up to 2100. The large scale GCM predictors were related to observed precipitation and temperature and future projections of climate were made under A1B and A2 scenario upto 21st century. At the end of the 21st century the mean annual temperature of the Jhelum river basin is predicted to increase by 1.43
    Keywords: Artificial Neural Network; Srinagar; Pahalgam; Qazigund ; Gulmarg; Scenario; Temperature; Precipitation.

  • Constructing Depth-Area-Duration Curves using Public Domain Satellite-Based Precipitation Data   Order a copy of this article
    by MARINA PATRICK, Yau Seng Mah, Frederik Josep Putuhena, Yin Chai Wang, Onni Suhaiza Selaman 
    Abstract: Dense network of rain gauges are used to accurately characterize the variation of rainfall over a less than ideal region such as Sarawak, Malaysia. This research aims to develop depth-area-duration (DAD) relationships of selected rainstorm event over Sungai Sarawak Basin by using public domain satellite-based precipitation data from Tropical Rainfall Measuring Mission (TRMM) product. Geographic Information System (GIS) was used to manipulate the 3-hourly accumulated precipitation dataset from TRMM and subsequently used to investigate spatial and temporal pattern of rainstorm. The findings suggested that rainfall depth decreases with increasing area for a given duration. This also implies that the remotely sensed information from TRMM product can be used as an alternative source of dataset to envelop rainfall DAD curves. Future work suggested would be to use the plotted DAD curves to estimate the probable maximum precipitation for the purpose of hydraulic structure designs.
    Keywords: Areal rainfall; depth-area-duration; extreme rainstorm event; Geographic Information System; isohyets; Kriging; North-East Monsoon; Sungai Sarawak Basin; Thiessen Polygon; Tropical Rainfall Measuring Mission.

  • Comparison of perturbation methods for rainfall and temperature data: case of a Belgian catchment   Order a copy of this article
    by Yann Peltier, Benjamin Dewals, Sebastien Erpicum, Michel Pirotton, Pierre Archambeau 
    Abstract: Analyses of hydrological impacts of climate change require appropriate methods for perturbing the rainfall and temperature (or evapotranspiration) time-series to represent future climate conditions. In this paper, two readily available tools for perturbing rainfalls and temperatures are compared: CCI-HYDR and KNMI-ADC. CCI-HYDR provides three scenarios, tailored for Belgium, for every decade until 2100. In contrast, KNMI-ADC provides 191 scenarios, at a regional level and for two time horizons (near and far future). The suitability and practical applicability of CCI-HYDR and KNMI-ADC tools is particularly examined for a medium-sized catchment in Belgium. Since these two perturbation tools deliver stationary time-series, the pros and cons of such an approach are compared to an alternate one which produces transient time-series. The CCI-HYDR tool is found suitable for forcing computationally intensive detailed hydrological models, as it provides a limited number of contrasting scenarios representing the range of possible future climate conditions. The KNMI-ADC tool enables scanning a broader spectrum of climate scenarios (although less extreme than in the CCI-HYDR tool), which makes it suitable for forcing multiple runs of fast conceptual hydrological models. The approach based on the transient stochastic tool is particularly computationally demanding due to its stochastic nature and is therefore also not optimal for use in combination with a detailed distributed hydrological model.
    Keywords: rainfall perturbation; climate change scenarios; hydrological modelling.

  • Laboratory Investigation for development of local scour depth model for varying shapes of obstruction   Order a copy of this article
    by Mir Bintul Huda, Mohd Akbar Lone, Javaid Ahmad Bhat 
    Abstract: This paper reports the effect of the shape of obstruction on local scour depth. Laboratory experiments were conducted on a tilting glass flume to study scour phenomenon around five obstructions of different shapes. Obstructions studied were chosen keeping in view not only the bridge piers but also some other structures, like obstructions in the flow channels e.g. a jetty, big boulder, any building in the coastal area, etc. Maximum local equilibrium scour, a dependent parameter, was studied as a function of flow parameters and shape parameters of the obstruction. A model was developed for the maximum local scour depth estimation in which maximum local scour depth (ds) is a function of Froude number (Fr), flow depth (y) and shape factor (Sf). The experimental findings depict a considerable effect of the shape of obstruction on the local scour depth.
    Keywords: discharge; flow depth; Froude number; scour; local scour; obstructions; shapes.

  • Mining Industry Impacts on Surface Water Quality in South Part of Armenia   Order a copy of this article
    by Marine Nalbandyan 
    Abstract: This paper deals with the quality of water of one of the tributaries of the river Araks- River Voghchi and its watershed basin. This article covers an investigation of common ions (Ca, Mg, Na, Cl, K, SO4, HCO3) and HMs (Cu, Mo, Cr, Ni, Mn, Zn, Co, Cd, Pb, Ag, Hg, As ) in waters of the River Voghchi and its tributaries. The performed river water research was underpinned by monthly monitoring data for 2003-2011. The impact of pollution sources and water quality formation factors were indicated. Assessment of the river water pollution with common ions and HMs were carried out, and dominating elements were indicated. The paper is highlight pollution level of the river water for the period of unstable economy and period of their stabilization, giving the comparative analysis of river water pollution.
    Keywords: mining industry; river water pollution; heavy metals; common ions; statistics; correlation analysis; River Voghchi; Armenia.

  • Application of non-parametric regression in estimating missing daily rainfall data   Order a copy of this article
    by Rachel Makungo, John Odiyo 
    Abstract: Most daily rainfall time series data are too short and/or possess missing records hindering them to perform reliable and meaningful analyses. Robust locally weighted scatter smoother non-parametric regression approach (NPR), with tricube weighting function was used to estimate missing daily rainfall data in the upper reaches of Nzhelele and Luvuvhu River Catchments in Limpopo Province of South Africa. Though a number of methods have been developed and tested, the approach proposed in this study has not yet been widely applied for estimating missing rainfall data. Model performance was evaluated using mean bias error, correlation coefficient, coefficient of determination, root mean square error and Nash Sutcliffe coefficient of efficiency. Model performance ranged from acceptable to excellent. Graphical fits of observed and estimated rainfall data showed a general agreement. Scatter plots indicated that there was no definite pattern of underestimation and overestimation of peak rainfall events in both calibration and validation runs. Scatter points for low rainfall values (mostly between 0-25 mm) were closer to the best fit line showing good agreement between observed and simulated rainfall values for most of the stations. The study showed that NPR effectively estimated missing rainfall data.
    Keywords: catchment; missing rainfall data; model performance; non-parametric; regression; time series; tricube weighting function.

  • Farm dam siltation and sediment source tracing in the Zeerust - Swartruggens area in the North-West of South Africa   Order a copy of this article
    by Samuel Che Nde, Munyaradzi Manjoro, Manny Mathuthu 
    Abstract: Soil erosion and dam siltation are two serious environmental problems facing farmers in South Africa. The study aimed to assess farmers perceptions on dam siltation and strategies employed to address it, and to assess the potential of sediment source tracing in a farming area in the North-West region of South Africa. Most of the dams in the study area were severely affected by siltation and the most important strategy used to address the problem was regular mechanical removal of the accumulated sediment. In relation to sediment tracing, lead-210 (210Pb) was found to be a more effective tracer than caesium-137 (137Cs) for distinguishing between surface and subsurface sediment sources. On the other hand, magnetic susceptibility offered better distinction of the sediment sources than magnetic remanance. Mass balance modeling indicated that 100 % of the sampled sediment Dam 1 originated from surface sources. The results reflect the complexity of sediment mobilization processes influenced by the nature and spatial distribution of rainfall and runoff connectivity in the catchments.
    Keywords: Farm dam siltation; environmental radionuclides; environmental magnetism; sediment source tracing; mass balance modelling.

  • Assessment of Future Groundwater Quality Using GIS for Bhimrad Area of Surat City (India)   Order a copy of this article
    by Manisha Desai, Jayantilal Patel 
    Abstract: Declination of water quality has become a global issue of concern as with the growth of human population, industrial and agricultural activities expand. Climate change threatens to cause major alterations in the hydrological cycle. The Bhimrad area of Surat city (Gujarat) is highly affected by ground water pollution because of its location in the vicinity of the industrial zone. There exists a creek adjoining Arabian Sea, in which all the wastewater of the city, including that of the industrial area is discharged, thus polluting land and other sources of water in the surrounding areas. The research paper shows the assessment of the groundwater quality degraded in the Bhimrad area of the Surat city on the basis of collection of past few year data of groundwater quality. Water quality has been assessed in term of the groundwater quality index (GWQI) by determining pH, Electric Conductivity, Total Dissolved Solids, Chlorine, Total Hardness, and Alkalinity in the premonsoon (May-June) and post monsoon (November-December) period for the years 2004, 2006, 2008, 2011, 2012, 2013, 2015. This research paper aims to analyze groundwater dilution used under the threat of pollution by identifying the prospects for improving the quality through artificial recharging that may impact groundwater quality. Calculation of percentage reduction in the groundwater quality parameters after recharging was carried out through which estimated improvement in GWQI using GIS, GWQI after recharging is analyzed for the years 2015 to 2050.
    Keywords: Sustainable Resources; Groundwater Quality; Water Conservation; GIS; Geological Information System.

  • Hydrological impacts of Climate Change on the Future Streamflow of Three Unregulated Catchments of the Australian Hydrologic Reference Stations   Order a copy of this article
    by Hashim Alsafi, Ranjan Sarukkalige 
    Abstract: A physically-based distributed hydrological model, the Block-wise use of the original TOPMODEL with the Muskingum-Cunge routing method (BTOPMC), is adopted to assess the impacts of future climate changes on the hydrological behaviour of three different sized contributing catchments of the Australian Hydrologic Reference Stations (HRSs); including Harvey River at Dingo-Road in Western Australia, Beardy River at Haystack and Goulburn River at Coggan in New South Wales. In this study, both historical and future modelled streamflow trends are compared and discussed. Firstly, the BTOPMC-model was calibrated and validated based on the observed hydro-meteorological data from the three contributing catchments. Then, the downscaled future climate signals from a multi-model ensemble of eight-GCMs of the CMIP5 under the RCP4.5 and RCP8.5 scenarios were used to force the calibrated BTOPMC-model to simulate the future daily streamflow at the three HRSs for the mid (2046-2065) and late (2080-2099) of the 21st-century. Nearly all GCMs predict a reduction tendencies in mean annual rainfall and an increase in temperature and potential evapotranspiration across the studied catchments. The mean annual streamflow measured at the three HRSs also shows reduction tendencies during the future periods under the two climate scenarios ranged between 26-53% at Dingo-Road HRS, 10-25% at Haystack-HRS and 6-33% at Coggan-HRS relative to the control run. The outcomes of this study are used to deliver valuable water management strategies to overcome the expected problem of water scarcity in the studied catchments.
    Keywords: Climate change; Hydrologic Reference Stations; physically-based simulation modelling; BTOPMC model; CMIP5; Australia.

  • Recent Approach in Producing Transparent Conductive Films (TCFs)   Order a copy of this article
    by Siavash Hosseinpour Chermahini, Kaveh Ostad-Ali-Askari 
    Abstract: Transparent conductive films (TCFs) are well known for their use in improving the efficiency of solar cell devices. The properties of transparent conductive materials are highly important due to their specifications and their influence on the performance of various devices. On the other hands, waste disposal is creating a global crisis which threaten the well-being of humans. Cheap electronic is one of the urgent current environmental problem. To this regards, different types of transparent conductive films have emerged, but indium tin oxide (ITO) and fluorine tin oxide (FTO) have been used in TCF sheets due to their optical transparency and electrical conductivity. However, some weaknesses, such a slow quality in the infrared region, the high cost of the elements, and their activity at low temperatures without the flexibility of transparency, have led to the search for a substitute. Moreover, TCFs need to be viable on a large scale for the next generation of optoelectronic devices as there is a lack of study in this area. Among all the candidates, a transparent hybrid of graphene and single-wall carbon nanotubes (SWCNTs) is a new trend in this area. Stable and homogeneous suspensions of GO sheets with strong hydrophilic and electrostatic repulsion properties are being used to produce TCFs. This trend has led to the creation of nanomaterials that exhibit better properties than their solo applications. Some techniques are able to increase the opt electrical properties with an additional transparency of more than 90%. Therefore, a comprehensive review was conducted for a new approach for the improvement of photovoltaic devices by means of a hybrid GP and SWCNT transparent conductive film.
    Keywords: Transparent conductive films (TCFs); single wall carbon nanotubes (SWCNTs); graphene oxide (GO); nanomaterial.

  • Estimating root zone soil moisture using multilayer feedforward neural networks based on Levenberg-Maquardt and scaled conjugate gradient algorithms   Order a copy of this article
    by John Odiyo, Rachel Makungo 
    Abstract: This paper presents the use of multilayer feedforward neural networks for root zone soil moisture estimation based on Levenberg-Maquardt (LM) and scaled conjugate gradient (SCG) algorithms. Data driven approaches such as artificial neural networks overcome some limitations of remote sensing, conceptual and semi-analytical models in root zone soil moisture estimation. This creates the need to compare neural networks training algorithms to determine those with best estimation accuracy. Observed volumetric soil moisture at 80 cm depth, rainfall and evaporation data were used to estimate soil moisture at 120 and 180 cm depths, within MATLAB. SCG trained network underestimated and/or overestimated soil moisture as compared to LM trained network. LM trained network has better performance and estimation accuracy. Estimated soil moisture is useful for irrigation scheduling, hydrological modelling, and groundwater recharge estimation in the study area.
    Keywords: algorithm; estimation accuracy; Levenberg-Maquardt; multilayer feedforward; neural networks; root zone; scaled conjugate gradient; soil moisture.

  • Prediction of discharge coefficient of combined weir-gate using ANN, ANFIS and SVM   Order a copy of this article
    by Abbas Parsaie, AmirHamzeh Haghiabi, Hazi Mohammad Azamathulla 
    Abstract: Flow measurement is an important issue for developing the water conservation projects and evaluating the performance of irrigation and drainage networks. Weirs and gates are the most common structures which have been widely used for flow measurement. The main defects related them are deposition of suspended matter behind the weirs and accumulation of floating matter on water behind the gates, respectively. therefore, the weir-gate structure has been proposed to solve them infirmities. In this study, predicting the discharge coefficient of Weir-Gate was considered using the artificial neural network (ANN), support vector machine (SVM) and adaptive neuro-fuzzy inference systems (ANFIS). For this purpose, the related dataset were collected from the literature. Assessing the performance of three models show that all of them have suitable accuracy, however, the SVM model with a coefficient of determination (R2=0.94) and root mean square of error (RMSE=0.008) has the best performance in comparison with others. During the preparation of SVM it was found that the radial basic function as kernel function has best performance among the tested kernel functions. Sensitivity analysis of applied models showed that the ANN is the most sensitive model in comparison with others.
    Keywords: Flow Measurement; Hydraulic Efficiency; Irrigation and Drainage Networks; ANFIS.