The hydraulic downpull forces that will be caused by 2-minute closures of the 16.5- by 21.0 foot Glendo Dam outlet works fixed-wheel gate were computed. Previous model studies (Hydraulics Laboratory Report No. Hyd-421, February 8, 1957) evaluated the hydraulic downpull for a stable condition of flow with the gate stationary at various openings. The present computation showed the added downpull caused by water trapped in the shaft above the gate during rapid closures to be about 4,500 pounds for gate openings larger than 3 feet. No additional downpull occurred at openings smaller than 3 feet. The maximum downpull of 40,000 pounds that occurs at 0.25 foot gate opening remains the maximum and unchanged. (Author).

This model study determined the energy dissipating efficiency of the hydraulic jump stilling basin for the slide gate controlled outlet works, and the hydraulic operating characteristics of the component features of the structure were observed. Norton Dam, a feature of the Missouri River Basin Project, is located on Prairie Dog Creek about 2 miles from Norton, in northwestern Kansas. The dam is approximately 6,400 ft. long at the crest and rises about 100 ft. above the riverbed. The spillway is located in the right abutment of the dam and consists of a 90-ft.-wide radial gate controlled overflow crest. The design spillway discharge is 95,000 cu ft/sec at the maximum reservoir elevation, 2341.0. The outlet works consist of a bellmouth entrance leading into a 48-in.-dia. circular conduit, a 2-ft. 9-in. sq. high-pressure emergency gate, a 38-in.dia. circular conduit, a 2-ft. 9-in.-sq. highpressure regulating gate, a 35-ft.-long diverging rectangular conduit, a 55-ft.-long vertically curved chute, and a 55-ft.-long hydraulic jump stilling basin. The last 21 ft. of the stilling basin consists of a 4:1 upward sloping apron. Maximum discharge is 385 cu.ft/sec. (Author).