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In the present study, the performance of the support vector machine for estimating vertical drop hydraulic parameters in the presence of dual horizontal screens has been investigated. For this purpose, 120 different laboratory data were used to estimate three parameters of the drop: the relative length, the downstream relative depth, and the residual relative energy in the support vector machine. For each parameter, 12 models were analyzed by using a support vector machine. The performance of the models was evaluated with statistical criteria (R2, DC, and RMSE) and the best model was introduced for each of the parameters. The evaluation criteria for the relative length of the vertical drop equipped with dual horizontal screens for the testing stage are R2 = 0.992, DC = 0.981 and, RMSE = 0.050. Also, the values of the downstream relative depth evaluation indicators for the testing stage are R2 = 0.9866, DC = 0.980 and, RMSE = 0.0064. For the residual relative energy parameter, the values of the residual relative energy evaluation indicators are R2 = 0.9949, DC = 0.9853 and RMSE = 0.0056. The results showed that capacity for this approach to predict the hydraulic performance of these systems with accuracy.

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One of the most effective ways to dissipate the destructive energy of water downstream of a flow control structure is the interference of water with air (such as a vertical drop). In this study, the hydraulic parameters of a vertical drop equipped with dual horizontal screens and with the subcritical upstream flow were investigated. Experiments were performed for two drop heights, two porosities, three relative distances between the screens, and a relative critical depth that was varied from 0.077 to 0.242. The results revealed that the relative distance between the screens does not affect the relative depth and downstream residual energy. On the other hand, increasing the relative length of the drop caused a decrease in the relative depth. Also, for a vertical drop equipped with a type 1 settling basin, the relative downstream depth decreased by more than 48%. The normal residual downstream energy and the relative total length of the drop are also decreased. The results also reveal that the use of dual horizontal screens transformed the regime of flow from super-to subcritical downstream of the drop.

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