Assessment of bed load estimators in rivers of Golestan province by developing applied software (STE)

Accurate prediction of flow and sediment discharges, as basic information, is important for many river engineering projects. To calculate the bed load in the rivers, many experimental and semi-experimental equations have been developed but depending on the hydraulic conditions and sediment profiles in each river, some of these equations may yield better results. In this research, by developing an applied software, the abilities of 27 equations of estimating bed load in rivers of Golestan province (Chehel-Chay, Khormaloo and Soosra), in which bed load is measured, have been evaluated. It should be noted that in this developed software quasi-two-dimensional models can be used for computing speed distribution in width of the river and also in estimating sediment loads. The software is also able to increase the accuracy of estimations by calculating calibration coefficients in the studied river. The results showed that by using the developed software, the best method for estimating bed load in the studied rivers is Yang's method. In this case, the abundance of discrepancy ratio between 0.5 to 2 for the rivers Chehel-Chay, Khormaloo and Soosra is 43.8%, 50% and 30.8% respectively. Also, using quasi-two-dimensional models, increases discrepancy ratio between 0.5 to 2 for the rivers Chehel-Chay, Khormaloo and Soosra by 6.3%, 6% and 8%, respectively. Results also showed that by calculating and applying a calibration coefficient, accuracy of methods can be improved for the studied rivers.