Dam engineering is currently experiencing a strong revival of labyrinth oriented weirs. Labyrinth weirs, with a repetitive constructional character and an increased specific discharge capacity, are a very good technical-economical compromise. The concept of Piano Key Weir (PKW), with alveoli developed in overhangs from a reduced support area, enables the installation of non-linear crests at the top of concrete dams. As a result it eliminates the main drawback of classical labyrinth weirs, and enables their use to rehabilitate numerous existing dams.

    Since the first implementation of piano key weirs by Electricité de France on Goulours dam (France) in 2006, at least eight PKWs have been built in France, Vietnam and Switzerland. Their operation over a few years has already provided the first prototype data. Other projects are under study, construction or planning in varied countries. On another hand, research programs are under progress all over the world.

    Following a first edition in 2011, Labyrinth and Piano Key Weirs II – PKW 2013 collects up-to-date contributions from people with various backgrounds, from engineers and researchers to academics. Summarizing the last developments on labyrinth oriented weirs, the book constitutes the state-of-the-art in research and application of piano key weir solutions, and will be invaluable to professionals and scientists interested in Dams Engineering.

    Keynote lectures

    The Piano KeyWeirs: 15 years of Research & Development – Prospect
    M. Ho Ta Khanh

    Improvement of labyrinth weirs shape
    A. Ouamane

    Embankment dam spillways and energy dissipators
    H. Chanson

    A. Physical and numerical modeling – Hydraulic capacity and scale effects

    Effects of the crest shape on the discharge efficiency of a type A Piano KeyWeir
    G.M. Cicero & J.R. Delisle

    Influence of geometrical parameters on PK-Weirs discharge with 3D numerical analysis
    V. Lefebvre, J. Vermeulen & B. Blancher

    Staged labyrinth weirs and their effects on the outflow hydrograph
    M.R. Dabling & B.P. Tullis

    Escouloubre Piano Key weir: Prototype versus scale models
    S. Erpicum, A. Silvestri, B. Dewals, P. Archambeau, M. Pirotton, M. Colombié & L. Faramond

    Scale effects related to the rating curve of cylindrically crested Piano Key weirs
    M. Pfister, E. Battisacco, G. De Cesare & A.J. Schleiss

    B. Physical and numerical modeling – Submergence and energy dissipation

    Submerged flow regimes of Piano Key weir
    F. Belaabed & A. Ouamane

    Experimental study on vertical velocity and submergence depth near Piano Key weir
    N. Sharma & H. Tiwari

    Discharge characteristics of Piano Key weirs under submerged flow
    G.M. Cicero & J.R. Delisle

    Comparative analysis of the energy dissipation on a stepped spillway downstream of a Piano KeyWeir
    A. Silvestri, P. Archambeau, M. Pirotton, B. Dewals & S. Erpicum

    C. Hydraulic and structural design

    Comparison of Piano KeyWeirs with labyrinth and gated spillways: Hydraulics, cost, constructability and operations
    G.S. Paxson, B.P. Tullis & D.J. Hertel

    An analytical approach for Piano Key weir hydraulic design
    O. Machiels, B. Dewals, P. Archambeau, M. Pirotton & S. Erpicum

    Estimation of A-type Piano Key weir rating curve
    M. Pfister & A.J. Schleiss

    D. Planned projects

    Design of a Piano-KeyWeir for Giritale Dam spillway in Sri Lanka
    H.M. Jayatillake & K.T.N. Perera

    Piano KeyWeir spillway: Upgrade option for a major dam
    M.A. Phillips & E.J. Lesleighter

    Designing a new spillway for the Rassisse Dam
    A. Bail, L. Deroo & J.P. Sixdenier

    Hydraulic scale model of the daisy-shape spillway on the Causse Corrézien dam
    P.E. Loisel, F. Duval & S. Chanourdie

    Application of the Piano KeyWeir spillway in the Republic of South Africa
    A.J. Botha, I.P. Fitz, A.J. Moore, F.E. Mulder & N.J. Van Deventer

    Hydraulic physical model of Piano KeyWeirs as additional flood spillways on the Charmine dam
    P.E. Loisel, P. Valley & F. Laugier

    Quipolly dam: A case study on customizing Fusegates® design for adverse spillway conditions
    M. Beretta, A.G. Merino, O. Cazaillet & R. Batterham

    E. Existing projects

    Overview of Piano KeyWeirs experience developed at EDF during the past few years
    F. Laugier, J. Vermeulen &V. Lefebvre

    The first commercial Piano KeyWeir in Switzerland
    P. Eichenberger

    Raising the bellmouth spillway at Black Esk reservoir using Piano Key weirs
    J.C. Ackers, F.C.J. Bennett, T.A. Scott & G. Karunaratne

    Spillway capacity upgrade at Malarce dam: Construction of an additional piano key weir spillway
    T. Pinchard, J.-L. Farges, J.-M. Boutet, A. Lochu & F. Laugier

    F. Future developments

    Effect of driftwood on hydraulic head of Piano Key weirs
    M. Pfister, A.J. Schleiss & B.P. Tullis

    Experimental and numerical study of the hydraulic performance of a trapezoidal Piano Key weir
    G.M. Cicero, J.R. Delisle, V. Lefebvre & J. Vermeulen

    Overview of Piano Key weir prototypes and scientific model investigations
    M. Leite Ribeiro, M. Pfister & A.J. Schleiss

    Effective spillways: Harmonizing labyrinth weir hydraulic efficiency and project requirements
    B.M. Crookston, G.S. Paxson & D.B. Campbell

    Author index


    Sébastien Erpicum, Frédéric Laugier, Michael Pfister, Michel Pirotton, Guy-Michel Cicero, Anton J. Schleiss