Sediment entering lateral intakes depends on the flow pattern at the intake entrance. Using a structure in front of the intake entrance can change this pattern and as a result the entering sediment. One of the effective method to change the pattern and manage sediment entering a lateral intake is to use a skimming wall. The removal of sediments from the intake entrance using a skimming wall led to reduction of sediment volume at the intake. To guide flow into the diversion canal and increase skimming wall performance a spur dike was utilized at the opposite side of the intake channel. In this study, the effect of the skimming wall's angle with the bank, a combination of spur dike and skimming wall and discharge changes on controlling sediments entering the intake, intake ratio and bed topography were investigated experimentally. The effect of a skimming wall with three angles (10°, 14°, and 18°) and a combination of skimming wall and spur dike on opposite sides of the intake were investigated. Conducting dimensional analysis, non-dimensional ratios were extracted and test variables were specified. Results showed that in the case of having a skimming wall combined with a spur dike, the amount of sediment entering the intake decreased by 81%, 78.5% and 76% on average for walls with angles of 10°, 14° and 18° respectively. Combining a skimming wall and spur dike has a higher effect on reducing sediments entering the intake compared with a skimming wall alone by about 15%.

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Estimating the value of discharge in water ways is an important factor in the flood controlling projects. Recently by advances in flood management, investigators have proposed to use the concept of compound section for modeling the flow characteristics in the natural waterways such as rivers. Several conceptual and theoretical approaches based on the idea of compound section have been proposed for estimating the discharge in rivers. In this study, the performances of the theoretical methods were assessed using performing series of experiments in straight prismatic compound open channel and also analyzing the published data in the literature. Analyzing the performance of theoretical methods shows that Divided Channel Method including vertical bounded line with the determination of coefficient (0.91) and root mean square error (0.02) is an accurate method through the theoretical approaches and only this method has suitable ability to apply for practical purposes.

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