CS32C - Concurrent Session 32C: Showdown at Cowboy Dam

The Los Vaqueros Reservoir Expansion (LVRE) Project is located on Kellogg Creek near Brentwood, California. Project objectives include raising the existing Los Vaqueros Dam by 58 feet, thereby increasing the reservoir’s storage capacity approximately 70%, while utilizing the existing chute and stilling basin. In addition, a new High Level Outlet Works (sluice) is to be constructed on the left abutment of the dam and will discharge onto the existing spillway and the base of the spillway chute extension. These features, particularly the sluice exit utilizing the full width of the spillway chute, made the spillway and sluice unique, placing their design beyond the state of knowledge expressed in existing literature on dams.

A physical hydraulic model, constructed at a 1:12 Froude scale, was designed and operated in conjunction with a computational fluid dynamics (CFD) model developed by AECOM to confirm and, if needed, adjust the design and hydraulic performance of the spillway and sluice conveying the probable-maximum flood (PMF) design discharge of 3,000 cubic feet per second. Moreover, a further objective of the study was to identify and verify the effects of adjustments to the design of the spillway and sluice. This presentation will summarize the system modifications and enhancements evaluated, and the benefits provided by combining a physical model with CFD simulations. Final design configuration and lesion learned with be presented.