Piano Key Weirs

Nonlinear weirs are attractive to practitioners as in some cases they provide a hydro-economical solution for new and rehabilitation projects. To academia, they remain a topic of interest due to a combination of the complex flow patterns they generate and the wide range of relevant geometries and application scenarios in rivers, dams, and other water resources applications with research topics including discharge efficiency, aeration, energy dissipation, local scour, driftwood and ice, and flow instabilities. Following three editions held in Europe and Asia (Liège, Belgium in 2011; Paris, France in 2013 and Qui Nhon, Vietnam in 2017), the 4th international workshop on Labyrinth and PKW moves to the United States, where several labyrinth and PKW prototypes coexist. As for the three previous editions, the workshop aims at bringing together people with varied background (engineers, researchers,...) to present and summarize the latest knowledge and developments on these non conventional hydraulic structures. Special emphasis will be put on planned and existing projects, data from real structures operation but also latest research developments.

Papers:

R&D – Floating Objects and Sedimentation

Labyrinth and PKW spillways in the USA Paxson G., Crookston – USA/Belgium

Behavior of floating trees at coexisting Piano Key Weir and gated spillway Yang J., Helgesson – Sweden

Effect of driftwood on the hydraulic performance of A-type PKWs in-stream or at reservoirs Venetz P., Pfister – Switzerland

Impact of sedimentation on the discharge capacity of labyrinth weirs Belzner F., Gebhardt – Germany

R&D – Hydraulics

Remote sensing of the 3D water surface downstream of labyrinth weirs Langohr P., Bung – Germany

Interfacial velocity characteristics downstream of a PKW vs. linear weir Belay B.S., Oertel – Germany

Model-Prototype upscaling of discharge capacity of Piano Key Weir Yang J., Nilsen – Sweden

Physical model investigations on nappe instabilities at labyrinth weirs Gebhardt M., Belzner – Germany

R&D – Design and Application

Studies of non-rectilinear weirs – From labyrinth to PKW Ouamane A., Lempérière – Algeria

Enhancing the hydraulic efficiency of PKWs – Recent research Yang J., Li – Sweden

Innovative association of Fusegate® and PKW Lempérière F., Chapuis – France

Innovative use of PKWs or labyrinth weirs for long dams in plains Ho Ta Khanh M. – Vietnam

R&D – Numerical Modeling

Sensitivity analysis of PKWs using CFD and empirical methods Oukaili F., Bercovitz – France

Experimental and numerical investigation of A-type rectangular side PKW Hussain S., Ahmad – India

Key width ratio influence on PKW discharge via OpenFOAM simulations Lüddecke L., Oertel – Germany

Investigation on flow field near A-Type PKW Quamar S., Ahmad – India

Project Applications

Projects – Lessons Learned

Lessons from Prado Dam labyrinth spillway design Diaz Y., Philips M., Allen J.D., Crookston B. – USA

Research and application of PKWs in Vietnam (2025) Ho Ta Khanh M., Dau Xuan T. – Vietnam

Case study: Burton Pond Dam – “Honey, I Shrunk the PKW” Bisio D. – USA

PKWs with orifice sluice Dau Xuan T. – Vietnam

Projects – Design

Arced labyrinth spillway for Dog River Dam Kirksey B., Tuladhar R., Hudock G. – USA

Springton Spillway: Arced labyrinth weir research and application Thompson S., Tullis B., Crookston B., Marchisello M. – USA

La Laye Dam design approach Roy M., Derrien S., Schaguene J.D., Dautois G. – France

3D modeling for Lower Crow Dam rehabilitation Bartels J., Bernedo Sanchez C. – USA

Projects – Construction

PKWs around the world Erpicum S., Jamali T., Crookston B. – Belgium

Nachtigal dam: 4917 m long labyrinth spillway Magnan D., Blancher B., Chapuis A., Guillemot T., Erpicum – France

High-altitude labyrinth weir design & construction Miller N., Provencher M. – USA

Stainless steel PKW at Oule Dam spillway Fournié Y., Tralli H., Alende J.D., Erpicum S. – France