Journal of Water Sciences Research: 4 (1)

Open Access Article

1 - Empirical Relation for Prediction of Sediment-Trapping Coefficient in the Experimental Flume of the Stepped Slit Check Dams
Mohammad Reza Pirestani Arash Razmkhah Amir Hosein Behroozi Fard

Eroded sediments from catchment areas transport by streams and deposit in downstream less steep areas. Despite reducing the useful life of various hydraulic structures including reservoir dams, flood walls, and bridges, this phenomenon changes the main river hydraulic c More

Eroded sediments from catchment areas transport by streams and deposit in downstream less steep areas. Despite reducing the useful life of various hydraulic structures including reservoir dams, flood walls, and bridges, this phenomenon changes the main river hydraulic conditions and increases the flood prone farms in the riverbank area. Check dams are among the structures that can prevent form such phenomenon. In addition to the technical performance, hydraulic structures including dams can provide beautiful view in the areas that have the potential to attract tourists. Stepped Slit Check Dams are combination of stepped and slit check dams. The present study investigated the effects of slope, discharge, gradation type, and check dam geometry on the sediment-trapping coefficient of the dam. Finally, a relation for prediction of the sediment-trapping coefficient in the reservoir of Stepped Slit check dams was presented. Manuscript profile

Open Access Article

2 - The Effect of Six-Legged Concrete Elements on Hydraulic Jump Characteristics
Mahmood Shafai Bejestan Maryam Khajavi Azade Ghavamifar

In the present study, the six legged concrete (SLC) elements are placed at the bed of a flume downstream of a chute in different layouts, densities and number of longitudinal rows of SLC elements. Each test was run for different flow conditions (Froude numbers ranged 5. More

In the present study, the six legged concrete (SLC) elements are placed at the bed of a flume downstream of a chute in different layouts, densities and number of longitudinal rows of SLC elements. Each test was run for different flow conditions (Froude numbers ranged 5.3 to 8.1). During each test, the water surface profile, the roller length and the jump length measured. Applying the experimental results, the sequent depth ratio and the dimensionless jump length calculated and compared to obtain the best layouts, the best densities and the minimum number of longitudinal rows of SLC elements. The results indicated that generally, the SLC elements can increase the shear force and consequently, reduce the jump length and the sequent depth of the jump. For the best layout, a linear type obtained when the SLC elements placed with 26% density. For the case of 100% density, the minimum longitudinal rows of SLC elements obtained to be equal to 21, or a basin 32% shorter than the smooth bed basin. Manuscript profile

Open Access Article

3 - 3D Numerical Simulation of the Separated Turbulent Shallow Flow around a Single Side Obstacle
A. Safarzadeh L. Esfandiary

In this paper, the performance of Reynolds Averaged Navier Stokes (RANS) simulations was evaluated to predict the flow structure developed by the presence of a sidewall obstruction in a uniform open-channel shallow flow. The study of these flow structures is important b More

In this paper, the performance of Reynolds Averaged Navier Stokes (RANS) simulations was evaluated to predict the flow structure developed by the presence of a sidewall obstruction in a uniform open-channel shallow flow. The study of these flow structures is important because they present in several real world configurations, such as groynes in rivers, where the erosion processes, mass transport, and influence of the flow hydrodynamics in ecological processes are still not well understood. Results of the numerical simulations were compared with the experimental laboratory measurements based on the Surface Particle Image Velocimetry (SPIV). It was found that the length of the main recirculation region obtained by two-equation models was 29% shorter than the measured one, while the predicted length by the Reynolds Stress Model (RSM) was in good agreement with the SPIV results. All of the performed RANS simulations were unable to predict properly the secondary separation region, which occurs immediately downstream of the side obstacle. This part of the flow field is a dead zone and due to extremely low velocity, the flow is laminar. Manuscript profile

Open Access Article

4 - Application of Soft Computing Methods in the Analysis of Velocity Field in Dividing Channel
Sohrab Karimi Hossein Bonakdari Hojat Karami Amir Hossein Zaji

The simplest water diversion method in irrigation systems is using intakes. Measuring the mean velocity is one of the essential hydraulic parameters in increasing the efficiency of the intake. In this study, the mean velocity was predicted for different width ratios of More

The simplest water diversion method in irrigation systems is using intakes. Measuring the mean velocity is one of the essential hydraulic parameters in increasing the efficiency of the intake. In this study, the mean velocity was predicted for different width ratios of an intake using ANN-MLP neural network model. In order to do that, the flow field within a 90-degree intake was first simulated three-dimensionally using ANSYS-CFX. The neural network used in this study includes 3 inputs; longitudinal coordinate (Y*), ratio of the branch channel to the main channel (wr), and mean velocity of the middle line of the channel cross section (V*line). V*lineis the average velocity in the vertical column of the branch channel, which has been measured by the ANSYS-CFX model after the validation. Comparison of the ANSYS-CFX results with the experimental ones indicated that this model, with mean Root Mean Squared Error (RMSE) of 0.013, has a proper accuracy in simulating the characteristics of the flow field within the intake. In addition, comparison of the obtained results from ANN-MLP model and the experimental results indicated that this model, with mean determination coefficient (R2) of 0.948, has a high performance in predicting the mean velocity of open channel intakes. Manuscript profile

Open Access Article

5 - Modeling Lake Urmia Water-Level Changes using Local Linear Neuro-Fuzzy Method
Arash Razmkhah Seyed Reza Alvankar Abbas Kakahaji

According to the water resources and climate change and challenges of Urmia Lake basin, which is the discharge and final destination of North West Rivers, a model was presented. Due to climate change and water resources in river basin such as rainfall, climate change in More

According to the water resources and climate change and challenges of Urmia Lake basin, which is the discharge and final destination of North West Rivers, a model was presented. Due to climate change and water resources in river basin such as rainfall, climate change in basin that has direct impact on evaporation over water catchment areas and lake water, this model can be provided. In addition, the inflow to the lake and the lake water-level fluctuations with the high accuracy and acceptable to experts could be estimated by this modeling and the lake water-level is going to be predicted up to one month. In order to simulate monthly fluctuations of the Lake water-level, this paper dealt with modeling the lake water level using two methods, Water Balance Equation and Local LinearNeuro-Fuzzy Network. In this study, to evaluate models’ accuracy, all of them were assessed by three most famous criteria including Root Mean Squares Error (RMSE), correlation coefficient (R), and similarity. The results obtained by Local LinearNeuro-Fuzzy Network modeling indicated that the concomitant use of cumulative flow (entering the lake), monthly precipitation and monthly evaporation on the lake surface provided the best performance with high accuracy regarding the simulated fluctuations of the monthly water level in Urmia Lake. Manuscript profile

Open Access Article

6 - Assessment of Saltwater Pollution in Azarshahr Plain Groundwater, Iran: Conjugating GALDIT Method and Geostatistics
Alireza Docheshmeh Gorgij Asghar Asghari Moghaddam

Overutilization of groundwater resources can put their quality under stress. It could be base on rapid declination in groundwater level leading to salt water intrusion in the coastal aquifers. The objective of this study was to map the vulnerability of salt water intrus More

Overutilization of groundwater resources can put their quality under stress. It could be base on rapid declination in groundwater level leading to salt water intrusion in the coastal aquifers. The objective of this study was to map the vulnerability of salt water intrusion of the Urmia Lake, Iran to nearby coastal aquifer (Azarshahr) using GALDIT method. The GALDIT index based on six parameters including; groundwater occurrence (G), Aquifer hydraulic conductivity (A), Level of water table above the sea level (L), Distance from shore (D), Impact of existing amplitude and extensive of saline water intrusion (I) and Thickness of aquifer (T) was computed in 21 observational points of the study area. A ranking system was developed both to give the relative importance of GALDIT factors and to differ categories within each GALDIT factor. After computing the GALDIT index for certain points, Geostatistic method was utilized instead of the layer overlaying to figure out the vulnerable zones. Results showed that except the central part of the study area and just 2 small portions in the northwest and southeast having moderate vulnerability hazards, others have a minimum vulnerability degree to the intrusion of Urmia Lake saltwater. Consequently, the GALDIT approach assisted to manage the monitoring of locations with high vulnerability risk. Manuscript profile

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