Somayeh Emami; Javad Parsa
Abstract
Due to the flow regime and consequently the sediment regime are not constantly in the watersheds, the prediction of sediment discharge is a great help in estimating and managing the sediment input to hydraulic structures. Measurement of sediment in the usual way is not justified in nowadays and may also ...
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Due to the flow regime and consequently the sediment regime are not constantly in the watersheds, the prediction of sediment discharge is a great help in estimating and managing the sediment input to hydraulic structures. Measurement of sediment in the usual way is not justified in nowadays and may also lead to human error. Therefore, in this study, three meta-heuristic optimization algorithms, including imperialist competitive algorithm (ICA), grey wolf optimizer algorithm (GWO) and election algorithm (EA), were used to predict the suspended sediment load of the Zarrineh river. In order to calculate the sediment discharge by the models, firstly, the necessary statistics and data were collected from the studied station in the period 1993-2015. After processing the data, 210 corresponding discharge and sediment data were selected. The corresponding discharge-sediment data from the study station were randomly separated into two parts, 70% for training and 30% for testing. In order to evaluate the performance of the algorithms, four statistics consist of R2, RMSE, MAE and the NSE were used. The results showed that GWO algorithm with values of statistical criteria R2=0.96, RMSE=228.86 ton/day, NSE=0.74 and MAE=67.32 ton/day, has a very high accuracy compared to other algorithms used which this would lead to comprehensive planning for the design and construction of hydraulic structures.
Hossein Kheirfam; Behzad Kheirfam; Yaaghoub Azhdan; Saleh Hossein
Abstract
Variability analysis of river sediment transport in different temporal and hydrological conditions is important in hydraulics and hydrological science and engineering. Otherwise, behavior analyzing of the riverian systems at the different temporal conditions is necessary in managerial decisions to control ...
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Variability analysis of river sediment transport in different temporal and hydrological conditions is important in hydraulics and hydrological science and engineering. Otherwise, behavior analyzing of the riverian systems at the different temporal conditions is necessary in managerial decisions to control and reduce sediment transport. However, knowledge about the type and amount of sediment in watersheds in various temporal and hydrological conditions is limited. Therefore, this study aimed to investigate the variability of bed and suspended load and bed to suspended load ratio. The 6-years period (1998-2003) data of bed and suspended load (g l-1) and discharge (m3 s-1) were collected from Yazdekan station of Qotour Chay River. The analyses also were carried out in Excel 2007 software. The results indicate that discharge increasing caused that the suspended load was increased and the bed to suspended load ratio was decreased at all seasons. As well, the lowest and highest bed and suspended load transport were occurred at the winter and spring, respectively. Amounts of minimum, maximum and median bed to suspended load ratio at spring, summer, autumn and winter were 5.02, 563.99 and 27.34%; and 0.075, 2034.91 and 135.80%; and 28.31, 659.15 and 184.94%; and 28.96, 457.61 and 169%, respectively. Also, during the study period the bed to suspended load ratio was varied about 0.7 up to 2034%. Therefore, using indirect methods to estimate sediment is not accurate because of complex behavior of sediment particularly bed load and bed to suspended load ratio with discharge. By and large, it is necessary that daily bed load measuring in sediment gauges.
Hossein Kheirfam; Seyed Hamidreza Sadeghi
Abstract
Measurment of river sediment transport in different temporal and hydrological conditions is important in hydraulics, hydrology and soil and water conservation science and engineering. Bed load is rarely measured because of difficulties and low efficiency of conventional samplers. The present study was ...
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Measurment of river sediment transport in different temporal and hydrological conditions is important in hydraulics, hydrology and soil and water conservation science and engineering. Bed load is rarely measured because of difficulties and low efficiency of conventional samplers. The present study was carried out in order to design a bed load sampler based on the conditions prevailing in the mountainous rivers flumes. The sampler with dimensions of 120 cm length, 60 cm height and 60 cm width was designed and subsequently fabricated. The accuracy of sampler was evaluated through comparing the bed loads estimations made by the designed equipment and those measured by collecting the whole discharged runoff to a 300 liters water tank installed at the outlet flume and with the help of statistical criteria. The t-test, relative erorr (RE) and relative bias (RBIAS) criteria were then used for statistical analyses. The results showed that the mean mesured bed load by water tank and designed sampler were 0.00635 and 0.0064 gl-1, respectively with no siqnificant differece (p<0.0763). In overall, the designed sampler had a high accuracy and efficiency in river bed load measurement with relative erorr and relative bias of about 8.5% and 0.107, respectively.
Mohammad Ebrahim Banihabib; Ehsan Emami
Abstract
Sediment yield of watersheds is considered as a problem of water resources management and operation. Considering important role of sedimentation, accurate measurement and estimation of it is important for national investment in water resources development. Accuracy of sediment yield estimation depends ...
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Sediment yield of watersheds is considered as a problem of water resources management and operation. Considering important role of sedimentation, accurate measurement and estimation of it is important for national investment in water resources development. Accuracy of sediment yield estimation depends on the estimation methods. There are different parameters affectingt sediment yield. These parameters should be considered in simulation of sediment yield. An artificial neural network model is used for estimation of sediment yield in this research. The model with proper structure and sufficient data is trained and tested and it can recognize the relation of the parameters and sediment yield. The proper structure is found to be MLP. The result of the model is compared with a regional analysis model and it shows notable increasing of accuracy by the artificial neural network model.
Hossein Rastgar; Mehdi Habibi
Abstract
Sedimentation is one of the most important problems in watershed management. The characteristics of geological formations are the most basic factors which have an important role in sediment yield. There are several methods for sediment estimation, but sediment transport equations and formulas have been ...
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Sedimentation is one of the most important problems in watershed management. The characteristics of geological formations are the most basic factors which have an important role in sediment yield. There are several methods for sediment estimation, but sediment transport equations and formulas have been developed for special conditions which may not represent all conditions. Therefore to find out which method is suitable for a specific river, it is required to compare each method with the measured data. The purpose of this research is to evaluate efficiency of different methods of sediment discharge estimation in Jagin River at Panhan hydrometric station. The methods of modified Einstein, Engelund-Hansen, Yang, Habibi and Van Rijn are used in this investigation. The required data was collected from Water Regional Organization of Hormozgan Province. The sediment yield is estimated based on concentration of collected samples of floodwater. Then, the collected data were checked and corrected. The conclusion shows that the modified Einstein method is the most suitable method for sediment estimation in the study area.
