The aim of this study, increasing energy dissipation in vertical drops with supercritical Flow in upstream. For this purpose, screen was used horizontally at the brink of vertical drop. The experiments were adjusted for a simple vertical drops with two porosity ratios of screens and three openings of the upstream sluice gate. Comparison of the results showed that the use of screens in vertical drop causes relative energy depreciation compared to simple vertical drops. However, the porosity of screens has an insignificant effect on energy dissipation. Evaluation and comparison of results related to the simple vertical drops and the ones equipped by screens indicated that incorporating the horizontal screens in these structures leads to the decreases in length of the stilling basin and elimination of the stilling basin.
