JWSS - Journal of Water and Soil Science

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This paper presents the results of an analytical and experimental study on the characteristics of hydraulic jump in a triangular channel. The analytical consideration is based on the momentum conservation law for the upstream and downstream sections of the jump. The experiments were carried out in a triangular channel of glass side walls with the vertex angle of 94.4°. A wide range of discharge and inflow Froude number were used in the experiments for two different opening heights of the upstream sluice gate. The main characteristics of the jump such as the sequent depth ratio, relative energy dissipation and water surface profile were investigated and the results were compared with those of the rectangular sections. The results showed that the triangular section is more efficient to dissipate the inflow energy. The efficiency of jump in a triangular channel is about 12% more than a rectangular channel for the same condition. As a result, hydraulic jump in a triangular channel needs a smaller tail water depth for a given inflow jet height and Froude number. Also, empirical relations and graphs are presented to determine the characteristics of the jump in triangular sections

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In this research, sediment production and delivery amount by Darabkola forest roads was estimated using the SEDMODL model. To evaluate the model results, the sedimentation rate in the above roads was directly measured using rainfall simulator. Also, the paired t-test, BIAS, RE and RMSE were used to assess the results. The analysis showed that the rate of sediment production from study roads' surface using the SEDMODL model and direct measurement under the rainfall simulation were 420.97 and 341.19 tons per year, respectively, and rate of sediment delivered to the stream with sediment delivery ratios of 42% and 51%, respectively, was about 177.58 and 174.02 tons per year. Also, results of the statistical methods of BIAS, RE and RMSE for the aforesaid model were 0.04, 17.59 and 0.71, respectively, and at 95% confidence level, no significant difference was obtained between the observed and estimated data. Therefore, the aforesaid model has the appropriate accuracy and efficiency to estimate the sedimentation rate of the Darabkola forest roads. It was also found that from among the input parameters of model, longitudinal slope of road, precipitation and sediment delivery factors were the most influential factors in the sediment production and transport, respectively.