Hydraulic Investigation of Piano Key Weir

Piano Key weir is a modified labyrinth weir that uses cantilevered up- and downstream overhangs in order to restrict its basis length. The small footprint on foundation of Piano Key weirs allows an easier placement on the crest of the existing dams such as concrete gravity dams and arch dams. The recent studies have shown that this new type of weir can provide more than four times as much discharge capacity as a traditional ogee-crested weir can at a defined hydraulic head and a constant width occupied by the structure on the dam. However, until now, there is not yet an empirical method that considered all of the published experimental data due to its geometric complexity. The aim of this present paper is to summarize the most pertinent information on Piano Key weir hydraulics in the preceding articles in order to provide a better understanding of how this innovative weir type operates and what the future researches which warrant further investigation are.