An important aspect of rivers’ hydraulics is the lateral distribution of velocity and boundary shear stress. The rivers appear to be in the form of a compound cross section at their extreme ends, such that water overflows from the main... more
An important aspect of rivers’ hydraulics is the lateral distribution of velocity and boundary shear stress. The rivers appear to be in the form of a compound cross section at their extreme ends, such that water overflows from the main channel of the river and enters the floodplains during floods. Due to their proximity to the river bank and their high latitude and fertile soil, floodplains have always been considered for various recreational, commercial, agricultural and residential purposes. Therefore, the awareness of the flow hydraulic in the floodplains is essential for the protection of humans, as well as the structures and installations in them. American Research Journal of Civil And Structural Engineering ISSN (Online): 2577-5944 Volume 3, Issue 1, pp: 1-10 Research Article Open Access
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ABSTRACT Deformation of various kinds of cross-sections was computed with the hypothesis that scour or deposition were directly related to shear stress computed by the Merged Perpendicular Method. Final stabilised cross section agrees... more
ABSTRACT Deformation of various kinds of cross-sections was computed with the hypothesis that scour or deposition were directly related to shear stress computed by the Merged Perpendicular Method. Final stabilised cross section agrees with theoretical stable shape. To estimate the deformation of a river bed, the results of a ID model which computes the volume of sediment eroded or deposited between two cross sections are used as a basis. Then, these volumes are transversely distributed in every section in relation with shear stress. The method is then applied to a reach of River Rhone.
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... pour calculer la repartition de 7 lacontrainte de cisaillement en travers d un canal rectiligne quelconque SAEED R. KI ... PJ (1974) Boundary shear distribution in compound channel with varying roughness distribution, Proceedings of... more
... pour calculer la repartition de 7 lacontrainte de cisaillement en travers d un canal rectiligne quelconque SAEED R. KI ... PJ (1974) Boundary shear distribution in compound channel with varying roughness distribution, Proceedings of the Institution of Civil Engineering, London ...
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... the Merged Perpendicular Method (MPM) (Khodashenas and Paquier, 1999), the Yang and Lim Method (YLM) (2002, 2005), the Guo and Julien Method (GJM) (2005), the Ramana Prasad and Russell ... They alternatively used the Normal Depth... more
... the Merged Perpendicular Method (MPM) (Khodashenas and Paquier, 1999), the Yang and Lim Method (YLM) (2002, 2005), the Guo and Julien Method (GJM) (2005), the Ramana Prasad and Russell ... They alternatively used the Normal Depth Method (NDM) in which hi of Eq. ...
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Collection of surface and subsurface waters in small seasonal rivers is very crucial, particularly in dry seasons. In this study a kind of intakes introduced, the system acts as a river drainage network. In this study an experimental... more
Collection of surface and subsurface waters in small seasonal rivers is very crucial, particularly in dry seasons. In this study a kind of intakes introduced, the system acts as a river drainage network. In this study an experimental model of the subsurface intake was constructed and the effective parameters such as upstream discharge, installation depth, and drains interval were evaluated. The results showed that the water diversion mostly influenced by the upstream flow rate. The very small drain interval caused the discharge of each drain to be reduced. It was also revealed that the total drained discharge in the very transmitting media was mostly controlled with the number of drain and drain interval did have a marginal effect. Finally the regression equations were established to estimate the discharge of each drain based on dimensional analysis, which facilitate the design of this structure. Keyword: subsurface intake, porous media, drainage system, design criteria
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for stability and river basin management and preventing soil and sediment losses in river basins, as well as conducting catchments conservation plans, it is necessary to estimate suspended sediment content in rivers. In the present study,... more
for stability and river basin management and preventing soil and sediment losses in river basins, as well as conducting catchments conservation plans, it is necessary to estimate suspended sediment content in rivers. In the present study, in order to select the best method of suspended sediment estimation at Barzoo, Baba Aman, Ghatlesh, Darband, Aghmazar, Tabarok Abad hydrometric stations located in Atrak river basin, corresponding data of flow and sediment discharges in the available statistical periods, were collected and analyzed. By creating a relationship between corresponding water and sediment discharges based on five linear, combined linear (multiline), linear with applied correction FAO, mean load within discharge classes and schematic method (tangent to maximum concentration line), we have selected an appropriate model which has the best predictability potential, based on the statistical indices. Therefore the index of root mean square error (RMSE), coefficient of determin...
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Due to the developments in the field of computer sciences, numerous models have recently been developed for hydrodynamic and water quality assessment in water-bodies. Among these models, the two-dimensional laterally averaged CE-QUAL-W2... more
Due to the developments in the field of computer sciences, numerous models have recently been developed for hydrodynamic and water quality assessment in water-bodies. Among these models, the two-dimensional laterally averaged CE-QUAL-W2 has received considerable attention worldwide and has become a commercial model in the recent decade. Considering the model’s abilities and the need to study the Doosti dam, the present study examines the water quality parameters of the Doosti dam Reservoir, such as phosphorus, Nitrate, etc., over a year-long period. The model was calibrated and yielded satisfying results, especially in the case of water temperature. Here, the results for the period from 2013 to 2014 have been presented. The results showed a three-month thermal stratification in the reservoir. Also, results of quality parameters showed that the Doosti dam reservoir is in danger of eutrophication.
Several ANN models were developed to prediction of monthly precipitation data in Mashhad synoptic station. From the total 636 monthly precipitation data (from 1958 to 2008), 580 data has been used for training networks and the rest... more
Several ANN models were developed to prediction of monthly precipitation data in Mashhad synoptic station. From the total 636 monthly precipitation data (from 1958 to 2008), 580 data has been used for training networks and the rest selected randomly has been used for validation of the models. To extract the precipitation dynamic of this station by ANN, a new approach of three-layer feed-forward perceptron network with back propagation algorithm was used. The sensitivity of the prediction accuracy to the content and length of input layer was investigated. Based on the most suitable parameters, two structures M531 and M741 have been selected. Statistical properties were calculated to examine the performance of the models and it was found that in the best model of monthly prediction, the correlation coefficient (R), Root Mean Square Error (RMSE), Mean Absolute Error (MAE), 0.93, 0.99 mm, 6.02 mm, respectively.
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Deformation of various kinds of cross-sections was computed with the hypothesis that scour or deposit were directly related to shear stress computed by the Merged Perpendicular Method. Final stabilized cross section agrees with... more
Deformation of various kinds of cross-sections was computed with the hypothesis that scour or deposit were directly related to shear stress computed by the Merged Perpendicular Method. Final stabilized cross section agrees with theoretical stable shape. The results of a 1D model which computes the volume of sediment eroded or deposited between 2 cross sections are used as a basis; these volumes are transversely distributed in every section in relation with shear stress. The method is then applied to a real reach.
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Weirs provide a simple method for measuring the volumetric flow rate in small to medium- sized streams or in industrial discharge locations. Sharp crest weirs can be built in different shapes, such as rectangular, triangular, trapezoidal,... more
Weirs provide a simple method for measuring the volumetric flow rate in small to medium- sized streams or in industrial discharge locations. Sharp crest weirs can be built in different shapes, such as rectangular, triangular, trapezoidal, circular and parabolic. In general, the discharge of these weirs is expressed by n Kh Q = , where the value of n varies with structure shape (e.g. 3/2 for rectangular weir and 5/2 for triangular weir) and isn't usually an integer number, then manual calculation of the discharge is facing a problem. In this study to facilitate the discharge calculations, the governing equations of parabolic crest weirs were reviewed and a simple equation was developed for computing the flow rate. Also, by using a physical model with different angles and heights, hydraulic characteristics of these weirs were investigated. The experimental results showed that with increasing the angle and height of parabolic weirs, the discharge coefficient was increased. The aver...
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Formation of Vortices is one of the serious problems in dam operation. In the present work, to study the vortex and its effects on orifice spillways of Karun III dam in southwestern Iran, partial (with only one orifice) physical models... more
Formation of Vortices is one of the serious problems in dam operation. In the present work, to study the vortex and its effects on orifice spillways of Karun III dam in southwestern Iran, partial (with only one orifice) physical models were constructed. Regarding to the special conditions in orifice spillways (changing discharge by changing the reservoir elevation) this study showed that when a decrease in reservoir elevation occurs, first strong vortices take place and after reaching a maximum value the strength of these vortices decreases. This research also showed that, by increase in vortex strength, the discharge coefficient may reduce down to 10 percent. Measuring the critical submerged depth showed that among theoretical methods, Gordon and Knauss have better results.
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Among the alternative techniques available for flood control, infiltration of rainwater is one of the most important methods to control stormwater effects. Conceptual river infiltration models are very useful for application to control... more
Among the alternative techniques available for flood control, infiltration of rainwater is one of the most important methods to control stormwater effects. Conceptual river infiltration models are very useful for application to control urban flood water, especially in the case of infiltration basins. Contrary to mathematical models, these models are very simple, and unlike empirical models, their parameters are very easy to calculate. Four selected models (DupuitForchheimer, Ernst, Miles and Morel-Seytoux) were employed for simulation of the infiltration process in infiltration basins. The study showed that the hydrograph computed by these models were closely similar to the real hydrograph. The three models (DupuitForchheimer, Ernst, and Miles) showed far lower sensitivity to their parameters than the MorelSeytoux one.
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In this paper, we have utilized ANN (Artificial Neural Network) modeling for daily rainfall forecasting in Mashhad synoptic station. To achieve such a model, we have used daily rainfall data of March as a month with high humidity and May... more
In this paper, we have utilized ANN (Artificial Neural Network) modeling for daily rainfall forecasting in Mashhad synoptic station. To achieve such a model, we have used daily rainfall data of March as a month with high humidity and May and December as months with medium humidity from 1986 to 2010 for this synoptic station. First, the Hurst rescaled range statistical (R/S) analysis is used to evaluate the predictability of the collected data. Then, to extract the precipitation dynamic of this station using ANN modeling, a new approach of three-layer feed-forward perceptron network with back propagation algorithm is proposed. Using this ANN model as a black box model, we have realized the hidden dynamics of rainfall through the past information of the system. The approach employs the gradient decent algorithm to train the network. Trying different parameters, some structures including GS 531 and GS 651 for March, GS 521 and GS 681 for May and GS 571 and GS 631 for December, have bee...
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In 1999, Merged Perpendicular Method (MPM) was developed by Khodashenas & Paquier in order to compute the distribution of boundary shear stress across irregular straight channels. For examination and validation of MPM, 4 methods are... more
In 1999, Merged Perpendicular Method (MPM) was developed by Khodashenas & Paquier in order to compute the distribution of boundary shear stress across irregular straight channels. For examination and validation of MPM, 4 methods are studied and compared with MPM. Guo & Julien and Prasad & Manson calculated the average bed and sidewall shear stress in smooth rectangular open channel. Berlamont et al, and Knight & Sterling calculated the average bed and sidewall shear stress in partially filled pipes open channel. Comparison with experimental data and 4 other methods shows that M.P.M matches well with the experimental data and provides good estimation of shear stress. Two advantages of MPM are: the determination of local shear stress and practicable in any shape of cross section.
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In this research, the effects of the development of Mashhad city (in Iran) on the amount of runoff generated were investigated. The urban catchment of this city with a total area of 328 km2 was divided into 288 sub-catchments, 399... more
In this research, the effects of the development of Mashhad city (in Iran) on the amount of runoff generated were investigated. The urban catchment of this city with a total area of 328 km2 was divided into 288 sub-catchments, 399 waterways, 398 nodes, and 5 outlets using GIS software. The pervious, impervious, residential, agricultural and street areas were then determined using the GIS software and Google Earth. The Curve Number (CN) was calculated for each sub-catchment. Three different methods of periodic block, uniform distribution and SCS (CN) II were used for selection of the storm discharges. Finally, the SCS (CN) II method was selected. The results of the modelling showed that the peak of flood in 2016 was 307, 259 and 177% greater than the years 1941, 1976 and 1986, respectively. In addition, the results showed that the central, northern, and northeastern regions (downstream of the city) were flooded due to the increase of the impervious surfaces and the insufficient capac...
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The Symbiotic Organisms Search Algorithm (SOS) is used as an algorithm based on the social behavior of Symbiotic Organisms in optimization of Non-linear 5 model parameters for flood routing. The data used in this article is 4 day... more
The Symbiotic Organisms Search Algorithm (SOS) is used as an algorithm based on the social behavior of Symbiotic Organisms in optimization of Non-linear 5 model parameters for flood routing. The data used in this article is 4 day observations from 30 November 2008 to 3 December 2008, which is located between the Molasani, and Ahwaz station on the Karun River. The time series data used included river inflow, storage volume, and river outflow. The results of the developed model with the Symbiotic Organisms Search Algorithm (SOS) were compared with the other Evolutionary algorithms including Genetic Algorithm (GA, and Harmony Search Algorithm (HS). The analysis showed that the best solutions achieved from the objective function by the SOS, GA, and HS algorithms were 143052.02, 143252.35, and 142952.45, respectively. The processes of these datasets determined that the SOS algorithm was premiere to GA, and HS algorithms on the optimal flood routing river problem.• In this article applied the Symbiotic Organisms Search Algorithm for Estimation of nonlinear parameters of the Muskingum hydrologic model of the Karun River located in Iran.• This method can be useful for managers of water, and wastewater companies, water resource facilities for predicting the flood process downstream of the rivers.• The present algorithm performs better than the other algorithms in the discussion of the optimization of Nonlinear 5 parameters of Muskingum model in flood routing.
ABSTRACT The isolation valves are crucial components of water distribution systems (WDS) that are used to shut down a segment of the network to repair or replace failed pipes. In this paper, an algorithm to find adjacent valves to isolate... more
ABSTRACT The isolation valves are crucial components of water distribution systems (WDS) that are used to shut down a segment of the network to repair or replace failed pipes. In this paper, an algorithm to find adjacent valves to isolate a failed pipe was proposed and the global resilience analysis method was implemented to find out the critical segments based on the isolation valves. The method was applied to Net3 network with three different isolation valve configurations. The location of isolation valves changed the resilience of the WDS considerably. The critical pipes and segments were also varied with different valve configurations. More than 60% of the most critical pipes are different between N valves and N-1 valves configurations. The resilience of limited valves configuration (with 52 valves) was 22% and 15% less than the resilience of N valves and N-1 valves configurations with 228 and 105 valves, respectively. Furthermore, with adding valves to the critical segments, the resilience can be enhanced noticeably.
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In this study operation of two types of circular and square collars has been investigated on a single cylindrical pier. The results showed that using of these two types of collars cause to reduction of scour depth especially under the bed... more
In this study operation of two types of circular and square collars has been investigated on a single cylindrical pier. The results showed that using of these two types of collars cause to reduction of scour depth especially under the bed level (elevation). This research showed that the square collar is more effective than circular shape in decreasing of the scour depth). The square and circular collars showed 70% and 50% decrease in rate of scour depth, respectively in compared with simple pier without collar.
Abstract This paper investigates how to achieve an equilibrium or stable state in a channel by taking into account widening and variations in its cross-section geometry dimensions. The current proposal is carried out by using an... more
Abstract This paper investigates how to achieve an equilibrium or stable state in a channel by taking into account widening and variations in its cross-section geometry dimensions. The current proposal is carried out by using an artificial intelligence technique, a Feed-Forward Neural Network (FFNN), which is trained by Extreme Learning Machine (ELM) algorithm to predict the banks profile morphology or shape profile characteristics of banks after stability. Moreover, the performance of proposed FFNN-ELM model is compared with eight famous previous traditional models and also a designed Non-Linear Regression (NLR). The analyses have been validated using a large number of experimental studies at different flow discharge rates. The results of ELM in comparison with NLR and traditional methods shows that the FFNN-ELM model has the best performance with lower error index values of Root Mean Squared Error (RMSE) equal to 5.6E-5 and Mean Absolute Relative Error (MARE) equal to 0.016, compared to NLR (RMSE = 2.2E-4 and MARE = 0.1225) and the most accurate traditional model which is related to Cao and Knight’s [15] model (RMSE = 0.119 and MARE = 0.1095). Therefore, the FFNN-ELM model proposed in this paper maintains a suitable computational efficiency, as second-degree polynomial, for its performance compared to NLR and previous traditional models in estimating shape profile of stable channels banks. Furthermore, the uncertainty of proposed FFNN-ELM is calculated by Monte-Carlo based simulation method to assess the reliability of model to predict bank profile shape. The uncertainty result shows the less uncertainty of the FFNN-ELM model in shape simulation with the percentage of observed data bracketed by 95 percentage prediction uncertainties (95PPU) equal to 81.35% and d-factor value equal to 1.26 in test stage. Furthermore, the sensitivity of FFNN-ELM model relative to input parameters (flow discharge, Q, and lateral distance from the centreline of the channel, x,) represents that in nearly all discharges, the sensitivity value is negative, indicates that by increasing the value of x parameter, the predicted value for the vertical level of the bank’s by model decreases. Moreover, by increasing the flow discharge, the sensitivity of the FFNN-ELM model to the two effective parameters of Q and x on the estimation of vertical level of the stable channels bank is increased.
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Abstract Determining the discharge coefficient is one of the most important processes in designing side weirs. In this study, the structure of Artificial Neural Network (ANN) and Radial Basis Neural Network (RBNN) methods are optimized by... more
Abstract Determining the discharge coefficient is one of the most important processes in designing side weirs. In this study, the structure of Artificial Neural Network (ANN) and Radial Basis Neural Network (RBNN) methods are optimized by a modified Genetic Algorithm (GA). So two new hybrid methods of Genetic Algorithm Artificial neural network (GAA) and Genetic Algorithm Radial Basis neural network (GARB), were introduced and compared with each other. The modified GA was used to find the neuron number in the hidden layers of the ANN and to find the spread value and the neuron number of the RBNN method, as well. GAA and GARB were tested for predicting the discharge coefficient of a modified labyrinth side weir he GARB method could successfully predict the accurate discharge coefficient even in cases where there is a limited number of train datasets available.
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Groundwater, as the key element of water resources, can play inevitably substantial role in managing groundwater aquafers. In fact, a ferocious demand for acquiring precise estimation of groundwater table is of remarkable significance for... more
Groundwater, as the key element of water resources, can play inevitably substantial role in managing groundwater aquafers. In fact, a ferocious demand for acquiring precise estimation of groundwater table is of remarkable significance for analyzing water resources systems. A wide range of artificial intelligence techniques were used to predict groundwater table with highly convincing level of precision. Hence, this investigation aims to present an integration of a neuro-fuzzy (NF) system and group method of data handling (GMDH) in order to forecast the ground water table (GWT). The NF-GMDH network has been improved by means of the particle swarm optimization (PSO) and gravitational search algorithm (GSA) as evolutionary algorithms. The proposed methods were developed using records of two wells in Illinois State, USA. For this purpose, datasets related to time series of GWT have been grouped into three sections: training, testing, and validation phases. Through training and testing phases, the efficiency of the NF-GMDH methods were studied. The performances of proposed techniques were compared to the performance of radial basis function-neural network (RBF-NN). Evaluation of statistical results indicated which NF-GMDH-PSO network (R = 0.973 and RMSE = 0.545) is capable of providing higher level of precision rather than the NF-GMDH-GSA network (R = 0.969 and RMSE = 0.618) and RBF-NN (R = 0.814 and RMSE = 1.41). Also, conducting an external validation for the improved NF-GMDH models showed the most permissible level of precision.
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Compound channels are hydraulic sections that consist of two parts including the main channel and the floodplain. The main channel conveys the usual runoffs and the basic discharge that often flows in the river. Predicting the flow... more
Compound channels are hydraulic sections that consist of two parts including the main channel and the floodplain. The main channel conveys the usual runoffs and the basic discharge that often flows in the river. Predicting the flow characteristics in the prismatic compound channels includes the effect of the interaction between a fast flow in the main channel and a slower one in the floodplains. This speed difference creates a shear layer at the interface between the main channel and the floodplain, which results in the exchange of the size of the movement between the main channel and the floodplains. The result is a reduction in the flow-conveyance capacity of the main channel and its increase in the floodplains, which should be considered in flow modeling. On the other hand, Flow3D software is a great software for Computational Fluid Dynamics that is used to solve complex geometry problems. The main objective of this study is to evaluate the Flow3D model in numerical simulation of...
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The energy dissipation in a gabion stepped spillway is compared with that of a rigid structure. The prototype had one, two or three steps, and models of rigid and gabion spillways with similar geometric dimensions were tested. The results... more
The energy dissipation in a gabion stepped spillway is compared with that of a rigid structure. The prototype had one, two or three steps, and models of rigid and gabion spillways with similar geometric dimensions were tested. The results showed that stepped gabion structures in one, two and three step modes, on average, increase the energy dissipation as compared with the rigid structures. In addition, the increase in flow rate reduced the efficiency of energy dissipation. Furthermore, in gabion spillways increasing the number of steps to three increased the energy dissipation. The effect of the second step on the rate of increase in the efficiency of energy dissipation was higher than the third step. The results indicated the high impact of throughflow in the gabion spillways on the energy dissipation. The second and third steps increased the energy dissipations compared to the one-step spillways; however, in the third step, the energy dissipations decreased slightly.
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Labyrinth side weirs are used as regulator outlets in river diversion structures , water conveyance systems and sewer networks . Herein , the flow around triangular labyrinth side weir with three different included angles (θ = 45 , 60 and... more
Labyrinth side weirs are used as regulator outlets in river diversion structures , water conveyance systems and sewer networks . Herein , the flow around triangular labyrinth side weir with three different included angles (θ = 45 , 60 and 90°) were numerically studied . The 3D RANS equations were solved and VOF method was implemented for free-surface tracking . Different boundary conditions and geometric dimensions were examined and their results were compared with experimental data. Different two-equation turbulence models were implemented. The water depth profiles and overflow discharge were compared with experimental results. The root mean square error of simulated water depth profile using standard k-e model was less than 1 mm. The diverted water discharge was computed with relative error less than 0.7%. The discharge of the labyrinth side weir was 1.7, 1.33 and 1.25 times the discharge of an equivalent normal side weir for θ = 45 , 60 and 90°, respectively.
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Abstract More accurate stable channel design methods are necessary for analyzing the complex bank profile cross sections of alluvial channels that achieve equilibrium state. This study introduces a new hybrid method that combines an... more
Abstract More accurate stable channel design methods are necessary for analyzing the complex bank profile cross sections of alluvial channels that achieve equilibrium state. This study introduces a new hybrid method that combines an adaptive neuro-fuzzy inference system (ANFIS), Differential Evolution (DE) algorithm and Singular Value Decomposition (SVD) to predict the bank profile of a threshold channel. SVD and DE serve to optimally determine the consequent linear parameters and antecedent nonlinear parameters of the TSK-type fuzzy rules in ANFIS. Moreover, by defining two objective functions and using the Pareto curve, the tradeoff of function is selected as the optimal modeling point. The authors carried out laboratory experiments at four discharge rates of 1.16, 2.18, 2.57 and 6.20 l/s to measure the coordinates of the points in a stable channel boundary profile. The ANFIS-DE/SVD results are compared with the results of a simple ANFIS model and 7 previous research works (based on numerical and experimental models and mathematical principles). The RMSE error index (0.019) of the ANFIS-DE/SVD model is lower than the ANFIS model (0.027), but both models outperform the best available model (CKM, Cao and Knight, 1998 ) (RMSE = 0.120). The ANFIS-DE/SVE model is more accurate for larger y (water surface level) values than the simple ANFIS model. Moreover, the superior performance of the hybrid ANFIS-DE/SVD over the simple ANFIS model is more pronounced at greater discharge rates. ANFIS-DE/SVD estimates the bank profile shape of a stable channel as a third-degree polynomial equation, which can be used to design and implement stable alluvial channels.
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The geometric dimensions and bank profile shape of channels with boundaries containing particles on the verge of motion (threshold channels) are significant factors in channel design. In this study, extensive experimental work was done at... more
The geometric dimensions and bank profile shape of channels with boundaries containing particles on the verge of motion (threshold channels) are significant factors in channel design. In this study, extensive experimental work was done at different flow velocities to propose a reliable method capable of estimating stable channel bank profile. The proposed method is based on gene expression programming (GEP). Laboratorial datasets obtained from Mikhailova et al. (Hydro Tech Constr 14:714–722, 1980), Ikeda (J Hydraul Div ASCE 107:389–406 1981), Diplas (J Hydraul Eng ASCE 116:707–728, 1990) and Hassanzadeh et al. (J Civil Environ Eng 43(4):59–68, 2014) were used to train, test, validate and examine the GEP model in various geometric and hydraulic conditions. The obtained results demonstrate that the proposed model can estimate bank profile characteristics with great accuracy (determination coefficient of 0.973 and mean absolute relative error of 0.147). Moreover, for practical calculations of channel dimensions, the model provides a specific mathematical relationship to solve problems with different discharge rates (Q) and particles with various median grain sizes (D50). The proposed model’s performance is compared with 8 relationships suggested previously by researchers (based on empirical and theoretical analyses) and a relationship obtained using a nonlinear regression model with different experimental data. The polynomial VDM and two exponential functions, i.e. IKM and DIM, are introduced as the superior existing models. According to the present study results, the proposed GEP model can predict the bank profile shape trend well and similar to the experimental datasets. Sensitivity analysis was also applied to assess the impact of each input variable (x, Q and D50) on the presented relationship. According to the current study, the GEP model provides a suitable equation for predicting the bank profile shape of stable channels.
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Abstract Measuring the bank profile shape when bank sediment particles are undergoing incipient motion (threshold) is notable for researchers. In the present study, an advanced laser gauge sensor instrument is utilized to measure the... more
Abstract Measuring the bank profile shape when bank sediment particles are undergoing incipient motion (threshold) is notable for researchers. In the present study, an advanced laser gauge sensor instrument is utilized to measure the coordinates of points located in a stable channel bank cross section. A robust Particle Swarm Optimization (PSO) algorithm combined with a Genetic Algorithm (GA) is developed in an Adaptive Neuro-Fuzzy Inference System (ANFIS) model to predict and compare the bank profile with measured data. The results show that the proposed ANFIS-PSO/GA optimization method had a determination coefficient (R2) and Mean Absolute Relative Error (MARE) of 0.9951 and 0.1575, respectively, and was thus highly accurate in stable bank shape prediction. With increasing flow discharge, the ANFIS-PSO/GA model accuracy augmented, and the model could simulate the widening of the water surface width quite well with an appropriate bank profile function that can be used in the design and implementation of stable channel geometry. Moreover, an uncertainty analysis was carried out to calculate the reliability of the proposed model based on the Monte-Carlo method. The results show that the ANFIS-PSO/GA model has less uncertainty in different hydraulic conditions of channels for predicting the vertical level of threshold bank profile and can predict satisfactorily the channel bank profiles.
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AbstractInfiltration trench is one of the best stormwater management practices to control excessive runoff volume in urban areas. Most of the methods or models employed for designing an infiltratio...
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MCDM (multi-criteria decision making) techniques are used to choose the best alternative among the relevant ones and rank the others. In this research, MCDM techniques were used to choose and rank the best places for constructing storage... more
MCDM (multi-criteria decision making) techniques are used to choose the best alternative among the relevant ones and rank the others. In this research, MCDM techniques were used to choose and rank the best places for constructing storage dams in Iran. To achieve this goal, the relevant information and data about dam construction situations were collected. Then, the recommended places for constructing storage dams were ranked by using MCDM techniques and according to the most suitable criteria which have been chosen based on experts’ opinions. To rank dam constructing project, three MCDM techniques, i.e., TOPSIS, AHP, and DEMATEL, were used. The results showed that the application of MCDM models by putting emphasis on economic, social, political, and technical criteria enables government and watershed managers to choose the best alternative(s) for constructing a storage dam.
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ABSTRACT In this paper, 13 models are compared against 6 sets of laboratory data for computation of bank profile of the stable channel. The applied models are Glover and Florey (GFM), Parker (PAM), Ikeda (IKM), Pizzuto (PIM), Diplas... more
ABSTRACT In this paper, 13 models are compared against 6 sets of laboratory data for computation of bank profile of the stable channel. The applied models are Glover and Florey (GFM), Parker (PAM), Ikeda (IKM), Pizzuto (PIM), Diplas (DIM), Diplas and Vigilar (DVM), Vigilar and Diplas (VDM), Cao and Knight (CKM), Babaeyan- Koopaee and Valentine (BVM1, BVM2), Yu and Knight (YKM), Dey (DEM) and Macky (MAM). A set of experiments was carried out by author in order to have a better comparison and evaluation of the results produced by the models. The experimental data revealed that only some of the applied models’ output such as IKM and DIM had a good agreement with the experimental results. Some of the models such as MAM and DEM, which use a complex numerical method for predicting the stable channel bank profile, did not necessarily provide better results. The comparisons indicated that all of the developed models have a considerable error comparing to the laboratory data, which necessitates additional studies. Among these models, the two applied models of PIM and VDM showed the best results with almost 25% error. Due to the simplicity of PIM approach, it can be a proper choice for the related engineering application.
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Nowadays along with the development of society, its impervious areas increase and therefore amount and volume of runoff accrue. Thus flood control in a pedestrian crossing, disorder of transport, contaminant flow and inundation in a... more
Nowadays along with the development of society, its impervious areas increase and therefore amount and volume of runoff accrue. Thus flood control in a pedestrian crossing, disorder of transport, contaminant flow and inundation in a residential area are the worry of designer and city manager. The primary goal of this research is simulation and evaluation of urban drainage system of East Eghbal basin which includes part of urban watershed in south and southeast of Mashhad city in Iran. The area of this basin is about 71 Km2. Due of complicacy in the simulation of an urban drainage system, after calibration and validation, MIKE SWMM used for rainfall runoff simulation and hydraulic response evaluation of urban drainage system. By investigation in historical rains, 17 and 3 storms (include 11 consecutive storms) were selected for single and continues simulation respectively. The rainfall chosen in this study was 30 /4/1998. It had greater peak hydrograph on all sub-catchments. The amount, average intensity, and duration of this rainfall were 14.1 mm and 4.1 mm/hr and 206 min, respectively. The results of the simulation showed that 6 conduits of urban drainage system have difficulty for carrying of the storm water. Finally, based on topographic maps, flooded channels position and surveying the study area, 3 appropriate natural sites for storm infiltration basins were recognized. The uUrban drainage system was evaluated again by the presence of these basins and results showed a noticeable reduction in the flood. KeywordsInfiltration Basin; GIS; MIKE SWMM; Urban Drainage System; Urban Flood
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In this paper, we have utilized ANN (artificial neural network) modeling for the prediction of monthly rainfall in Mashhad synoptic station which is located in Iran. To achieve this black-box model, we have used monthly rainfall data from... more
In this paper, we have utilized ANN (artificial neural network) modeling for the prediction of monthly rainfall in Mashhad synoptic station which is located in Iran. To achieve this black-box model, we have used monthly rainfall data from 1953 to 2003 for this synoptic station. First, the Hurst rescaled range statistical (R/S) analysis is used to evaluate the predictability of the collected data. Then, to extract the rainfall dynamic of this station using ANN modeling, a three-layer feed-forward perceptron network with back propagation algorithm is utilized. Using this ANN structure as a black-box model, we have realized the complex dynamics of rainfall through the past information of the system. The approach employs the gradient decent algorithm to train the network. Trying different parameters, two structures, M531 and M741, have been selected which give the best estimation performance. The performance statistical analysis of the obtained models shows with the best tuning of the developed monthly prediction model the correlation coefficient (R), root mean square error (RMSE), and mean absolute error (MAE) are 0.93, 0.99, and 6.02 mm, respectively, which confirms the effectiveness of the developed models.
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L'infiltration des eaux pluviales est, parmi les techniques alternatives, l'une des plus importantes pour controler les effets du ruissellement. Les modeles conceptuels d'infiltration pluviale sont tres pertinents pour simuler... more
L'infiltration des eaux pluviales est, parmi les techniques alternatives, l'une des plus importantes pour controler les effets du ruissellement. Les modeles conceptuels d'infiltration pluviale sont tres pertinents pour simuler les techniques alternatives, specialement pour les bassins d'infiltration. Contrairement aux modeles mecanistes, ces modeles sont tres simples, et contrairement aux modeles empiriques, les parametres de ces modeles sont tres faciles a trouver. 4 modeles d'infiltration pluviale, Dupuit-Forchheimer, ERNST, MILLES et MORELLE ont ete compares. Les trois modeles D-F, ERNST et MILES sont susceptibles d'etre applicables aux techniques alternatives, plus precisement pour les bassins d'infiltration et les chaussees a structure reservoir (et probablement pour les tranchees).
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Predicting behavior and the geometry of the channels and alluvial rivers in which the erosion and sediment transport are in equilibrium is one of the most important topics in river engineering. Various researchers have proposed empirical... more
Predicting behavior and the geometry of the channels and alluvial rivers in which the erosion and sediment transport are in equilibrium is one of the most important topics in river engineering. Various researchers have proposed empirical equations to estimate stable river width (W). In this research, empirical equations were examined and tested with a comprehensive available data set consisting of 1644 points collected from 29 stable rivers in various parts of the world. The data set covers a wide range of flow conditions, river geometry, and bed sediments. This data set is classified in two groups (W < 600 m and W ≥ 600 m) for presenting the new models. The new linear and nonlinear multivariable equations were fitted to these two groups, and the best models were selected by preliminary tests and diagnostic determined for each group. The determination coefficient of these models ranged from 0.87 to 0.96. The results show that the models presented in this paper are more accurate with respect to the previously presented models. In the second part, “Artificial neural networks,” perceptron was used and a new methodology for estimating stable channel width was developed. Comparison of the statistical methods presented in this paper and the results of perceptron neural network revealed preferential recent method.
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Stilling basins dissipate energy to form hydraulic jumps and rotational flows. Hydraulic jump and rotational current phenomenon produce pressure fluctuation at the bottom of stilling basins. In the present study, pressure fluctuations and... more
Stilling basins dissipate energy to form hydraulic jumps and rotational flows. Hydraulic jump and rotational current phenomenon produce pressure fluctuation at the bottom of stilling basins. In the present study, pressure fluctuations and their locations have been studied in a physical model of Namrod Dam. Results showed that fluctuations in presence of jump in the basin are high and, therefore, the fluctuation factors are, respectively, high. In positive pressure coefficient (CP+), it is evident that when a jump is present, the turbulence and disturbance factors increase and, therefore, the pressure fluctuations go up, respectively. In negative pressure coefficients (CP−), as is expected from positive pressure coefficients, the maximum pressure fluctuations occurred at Q/Qmax = 0.47 with regard to forming a complete hydraulic jump at this discharge. Regarding available empirical equations, the thickness of slab for different hydraulic conditions was calculated and compared in one-dimensional (1D) and two-dimensional (2D) conditions. By analyzing collected data, it was observed that, results of 1D were underestimated in comparison to 2D calculations. Concrete slab thickness could be observed that fluctuations have significant effect on thicknesses. However, such calculations can provide designers with general ideas on how to better understand the conditions.