Flow over spillways or underneath gates has a tremendous amount of potential
energy, which is converted into kinetic energy downstream control structures. This
energy should be dissipated to prevent the possibility of excessive scouring of the
downstream waterway bed, minimize erosion and undermining of structures, which
endanger the structure safety. In this paper, an experimental study was conducted to
predict the scour geometry downstream a sloped spillway and to minimize the
scour using a stepped spillway with certain arrangements. It was found that the
using of stepped spillway instead of the sloped one reduced the relative scour depth
and increased the relative energy loss and the spillway with three steps gave the
smallest value of scour depth. The dimensional analysis was employed to drive
expressions correlating the different variables affecting the scour phenomena.
Prediction equations were developed using the multiple linear regression (MLR) to
model the relative scour depth Ds/yup and the relative the relative energy loss
ΔE/Eup. A good agreement was obtained between the predicted and the measured
values. Finally, this study yielded conclusions which can be recommended in the
design procedure and practical applications.