throughout history dams have been important structures in water storage. to avoid overtopping, damage, and or failure of a dam, adequate spillway is needed to release excess water from upstream floods. researchers found that spillways have to be made nonlinear in order to reach an economic structure with high performance. a piano key weir is one of the best solutions. piano key weirs are the mo...

This investigation deals with the mechanics of movement singular quartz gravel and coarse sand riverbed particles upstream over inlet key three Type A piano weir (PKW) models, which were recorded a high-speed camera. Acoustic Doppler velocimeter was used to obtain bed shear stress. The sediment threshold regime compared previous investigations found be within ranges. Generally, particle deceler...

Free crest spillways are hydraulically efficient and safe in operation. Since their discharge capacity is directly proportional to the crest length several types have been developed with the purpose to increase the length of the latter. Among these types traditional labyrinth weir spillways have been studied and used for a long time. Their hydraulic performance and the effect of the involved ge...