Apron and Cutoff Wall Scour Protection for Piano Key Weirs

Piano key (PK) weirs are used in a variety of flow control structure applications, including spillway crests and open channel diversion structures. However, to the best authors’ knowledge, structure-specific design guidance for scour mitigation is still needed. To fill this gap systematic experimental campaign was conducted by testing different configurations horizontal aprons with cutoff wall. Protection structures were located at toe PK weir. Namely, experiments performed large-scale assess effect three apron lengths on downstream hole geometry under hydraulic conditions. It observed that deflects plunging jets originating from weir, thus significantly reducing scour. Experimental evidence allowed corroboration significant depth reduction occurs an length 1.5 times weir height, longer found provide marginal benefits. Finally, also provided herein tools estimate main characteristics help practitioners optimizing design.