Workshop on Nonlinear Weirs

A half-day workshop on 25th October 2022 on the sustainable design and construction of nonlinear weir.

Sebastien Erpicum

Liege University,

Dr. Erpicum has been one of the key pioneers in researching, understanding, and publishing information related to the development and implementation of the innovative Piano Key Weir concept and its application to several dam rehabilitation projects in France and abroad.

Brian M. Crookston

Utah State University,

Dr. Brian consulting and research interests are focused on water conveyance, including the design of hydraulic structures, nonlinear spillways, flow acoustics, energy dissipators, scour, fish passage, and physical and numerical modelling.


Inadequate conveyance capacity, significant hydrologic loadings on embankments and structures, and operation and maintenance are common challenges and safety issues that often instigate the need for risk-reduction measures and/or rehabilitation. Nonlinear weirs such as labyrinth and piano key weirs are a particularly efficient approach to address these concerns. These weirs provide a crest length greater than the width of the channel and are commonly used in a variety of applications, including run-of-river structures, dam rehabilitation and new dam projects. In some cases, these structures may be complimentary to or even an alternative to gated spillways, which require operation and maintenance and can cause downstream flooding if misoperation or failure occur. Because of their hydraulic performance and site-adaptive geometries, these types of weirs are of increasing interest to those involved in water infrastructure, including practitioners, researchers, regulators, and owners. However, these types of weirs have complex geometries and hydraulic behaviors that pose a challenge when developing an efficient design.

The workshop will cover all relevant stages of a labyrinth and a piano key weir project, from the first theoretical design to detailed studies and practical considerations related to the construction. The workshop will be divided in two parts, each related to a specific type of weir. During both parts, several real examples in France and the USA will illustrate the technical presentations and time will be devoted to Q/A and discussion.