A review on physical models of scour holes below large dams in Iran

Water nappes or plunging jets, released by spillways terminating to flip buckets, create scour holes at downstream valleys of large dams. Physical modelling and empirical formulae are used to predict geometry of the scour holes. In this paper, four physical models of unlined plunge pools below large dams in Iran were reviewed. Results showed that the models generally overestimated the ultimate scour depth in comparison with the selected empirical formulae. However, good agreement of the observed scour depths at Karun 1 prototype was found with the formulae. Furthermore, the longitudinal location of the scour hole was investigated and compared with semi-empirical relationships for jet trajectory.