Spillway and Stilling Basin Lower Monumental Dam Snake River, Washington: Hydraulic Model Investigation.
ARMY ENGINEER DIV NORTH PACIFIC BONNEVILLE OREG DIV OF HYDRAULIC LAB
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A 3-bay-wide section of upstream approach, spillway and stilling basin, and exit channel were reproduced in a 142.47-scale hydraulic model. Flow conditions adjacent to the spillway were also observed in a 1100-scale general model. The model tests indicated that capacity of the spillway would be slightly less than computed because of losses at the abutments. Pressures on the crest and piers were above the range of cavitation for all discharges and methods of spillway operation. The original stilling basin would not contain the hydraulic jump at the spillway design flow of 850,000 cfs. Additional excavation in the exit channel, or erosion of the river bed to elev 392, provided the desired capacity for the stilling basin. Minimum excavation requirements and optimum heights of vertical and sloping end sills were determined. Modified author abstract
- Civil Engineering