Author(s): Julie D. Allen; Michael A. Phillips; Brian M. Crookston; Yajayra Diaz

Linked Author(s): Brian Crookston

Keywords: Labyrinth; weir; spillway; submerged; converging chute; high head

Abstract: The U.S. Army Corps of Engineers has evaluated the hydraulic performance of the proposed 17,800 m3/s capacity labyrinth weir spillway at Prado Dam, located in Los Angeles, California, USA. The new crest would consist of 7-cycle labyrinth weir, arced upstream into the reservoir with varying weir wall heights from 8.5 m to 12.6 m and upstream head over the weir of up to 10 m. The labyrinth weir discharges into a mild sloping asymmetrical converging concrete chute spillway terminating with a submerged flip bucket energy dissipation structure. Hydraulic performance was evaluated using both a 1:38 Froude Scaled physical model and a computational fluid dynamics (CFD) model of the reservoir approach, the 7-cycle labyrinth, the spillway chute, flip bucket, and downstream channel. This paper compares the complicated arced labyrinth weir hydraulics, including head- discharge data, to available research data from straight labyrinth weirs in a flume and other arced labyrinth weirs and discusses the unique conditions at Prado that led to the successful design with the observed weir inefficiency. The results provide practitioners insights and data to consider when designing unique labyrinth weir structures and demonstrate how inefficiency in hydraulic performance is balanced with project objectives and economics, leading to unique designs in practical applications.

DOI: https://doi.org/10.3929/ethz-b-000675921

Year: 2024