The 48 MW Jim Falls Hydropower Redevelopment project on the Chippewa River, Wisconsin, required extensive model studies to facilitate the debris sluicing and to prevent intermittent vortex formation in front of the powerhouse intake. Debris, consisting mainly of natural materials from a forested and agricultural watershed, had to be directed to a gated spillway adjacent to the powerhouse (Fig. 1). To accomplish that goal, the surface circulation in the headwater pool had to be reversed. Vortices formed preferentially at two locations near the ends of the powerhouse, and were highly unstable in space and time. The highly irregular headrace geometry, in terms of width and depth, was found to be the cause of the undesirable flow features. A series of headrace modifications resulting in a more symmetrical approach channel configuration provided a debris flow pattern away from the powerhouse intake, and reduced frequency and strength of vortex formation to acceptable levels. A description of effective and ineffective design changes will be given.
Reprinted from Waterpower '87 Proceedings of the International Conference on Hydropower ASCE, Portland, OR, August 19 -21, 1987.
Stefan, Heinz G.; Voigt, Richard L. Jr.; Lindblom, Karen L. C.; Ainsworth, Bruce; Colgan, Patrick.
Headrace Design Studies for the Jim Falls Hydro-Redevelopment Project.
St. Anthony Falls Laboratory.
Retrieved from the University of Minnesota Digital Conservancy,
Content distributed via the University of Minnesota's Digital Conservancy may be subject to additional license and use restrictions applied by the depositor.