Jim Falls Hydropower Model Study

The Jim Falls hydroelectric power plant is located on the Chippewa River at the town of Jim Falls, Wisconsin. An aged 11 MW existing facility at the location is being replaced by a more efficient 48 MW peak power plant. The new design includes a much larger headwater pool which is to be formed by a new earth embankment (see Fig. 1.1). The new powerhouse is situated approximately 0.2 miles upstream of the existing facility. The project is being developed by Northern States Power Company (NSP), Wisconsin, in conjunction with NSP, Minnesota. Project design is being undertaken by B1ack & Veatch, headquartered in Kansas City, Missouri; Mead and Hunt headquartered in Madison, Wisconsin; and Motor Columbus, headquartered in Baden, Switzerland. Hydraulic model studies were conducted at the St. Anthony Falls Hydraulic Laboratory, University of Minnesota. The purpose of these experiments was to evaluate and test various design alternatives for major hydraulic structures of the project. This report summarizes and documents that activity. A videotape (27 min.) supplements this report and shows actual flow conditions in the 1:60 scale model. The Jim Falls Hydro Redevelopment Project includes a two unit powerhouse, new headwater pool with pilot channel, tailrace channel and an auxiliary spillway next· to the powerhouse. This new spillway has three tainter gates topped with flaps for debris sluicing. The auxiliary spillway design flow is 65,000 cfs. The proposed headwater. pool will include a portion of the existing diversion canal (Fig. 1-1) and. will extend into the Chippewa River below the existing bridge.