Local scour characteristics downstream of diversion barrages

This paper reports on experiments carried out on a physical model of a typical river diversion barrage (weir with gated control) to study local scour characteristics downstream of its apron under various hydraulic conditions. Relations for maximum scour depth and its location from the apron edge are derived using non-linear regression and back-propagation artificial neural network techniques from the experimentally observed data. Variations of scour depth with discharge, tail water and gate opening are examined to determine the possible critical local scour condition downstream of a barrage. Finally, the case of an actual prototype scour for a barrage due to uncontrolled flow through one of its damaged gates is investigated. The scour profile for this study is predicted by numerical simulation carried out with a finite-volume-based computational fluid dynamics software package (Fluent) and compared with field measurements.