Investigation and analysis of scour downstream of a spillway

Local scour downstream of spillways due to hydraulic jump is considered the most complicated and tedious problems which threats the overall stability of the spillway. Throughout this paper, eighty experimental runs were carried out to investigate the effect of using cylinder blocks fixed on the back slope of the spillway on the scour hole dimensions downstream of spillway under different flow conditions. Case of smooth spillway was included to estimate the influence of the considered modifications. Experiments were performed using different diameters, lengths, and arrangements of cylinder blocks with different discharges. Data collected from the experiments were analyzed and graphically introduced. Furthermore, experimental data for smooth spillway were compared with scour formulae for other researchers. Finally simple formulae were predicted to estimate the different scour and deposition parameters. Use of concrete cylinder blocks will assist engineers in the design of spillways. (C) 2017 Ain Shams University.