Abstract
In terms of the importance of safeguarding regulators, this research was commenced with the impartial studying of the performance of sill, experimentally, where Naga Hammadi Barrage was taken as a case study. An experimental work was carried out in Hydraulic Research Institutions, Egypt. Different discharges and different sill forms were tested. The effect of the sill on different variables was investigated. Measurements were undertaken and analyzed. Moreover, empirical equations were deduced and the results were discussed. Results indicated that sills, especially with right and slopped faces at both up- and down-stream, have a great effect on the examined variables. The results detailed some considerations concerning the tested variables concerning the deduced equations.