Lower Monumental Dam, Snake River, Washington: Hydraulic Model Investigation
Lower Monumental Dam, Snake River, Washington: Hydraulic Model Investigation

Author:

Publisher:

Published: 1974

Total Pages: 0

ISBN-13:

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Lower Monumental Dam is located 41.6 miles above the mouth of the Snake River and 35 miles northeast of Pasco, Washington. Maximum heat on the project is 103 ft; the project design discharge is 850,000 cfs. Excavation requirements, diversion plans, structures locations, and methods of operation were studied in a 1:100-scale model that reproduced 2.4 miles of river channel and pertinent overbank topography. The first-step cofferdam and diversion channel were designed to protect the work area against discharges to 250,000 cfs. The diversion channel and cofferdam cells were revised and the location of a temporary fishway was determined by means of the model study. Tests of the second-step cofferdam, designed for 200,000 cfs, indicated that the height of four upstream cells should be increased 3 ft, the three downstream temporary fishway entrance. (Modified author abstract).

Lower Monumental Dam, Snake River, Washington: Hydraulic Model Investigation
Lower Monumental Dam, Snake River, Washington: Hydraulic Model Investigation

Author:

Publisher:

Published: 1974

Total Pages: 0

ISBN-13:

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Lower Monumental Dam is located 41.6 miles above the mouth of the Snake River and 35 miles northeast of Pasco, Washington. Maximum heat on the project is 103 ft; the project design discharge is 850,000 cfs. Excavation requirements, diversion plans, structures locations, and methods of operation were studied in a 1:100-scale model that reproduced 2.4 miles of river channel and pertinent overbank topography. The first-step cofferdam and diversion channel were designed to protect the work area against discharges to 250,000 cfs. The diversion channel and cofferdam cells were revised and the location of a temporary fishway was determined by means of the model study. Tests of the second-step cofferdam, designed for 200,000 cfs, indicated that the height of four upstream cells should be increased 3 ft, the three downstream temporary fishway entrance. (Modified author abstract).

Spillway and Stilling Basin Lower Monumental Dam Snake River, Washington: Hydraulic Model Investigation
Spillway and Stilling Basin Lower Monumental Dam Snake River, Washington: Hydraulic Model Investigation

Author:

Publisher:

Published: 1967

Total Pages: 71

ISBN-13:

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A 3-bay-wide section of upstream approach, spillway and stilling basin, and exit channel were reproduced in a 1:42.47-scale hydraulic model. Flow conditions adjacent to the spillway were also observed in a 1:100-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).

Fish Ladders for Lower Monumental Dam Snake River, Washington
Fish Ladders for Lower Monumental Dam Snake River, Washington

Author: Louis Z. Perkins

Publisher:

Published: 1973

Total Pages: 70

ISBN-13:

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Facilities for passing fish upstream over Lower Monumental Dam include a powerhouse collection system and a 16-ft-wide fish ladder on both sides of the river. A straight, 35-pool section of fish ladder and a typical fishway entrance weir were reproduced in a 1:10-scale model. Performance of a pair of typical diffusion chambers was studied in a 1:8-scale model that included portions of the adjacent supply conduit and fish ladder. Fishway weirs of original design, with 5-ft-long overflow crests at each end of a 6-ft-long nonoverflow section, upstream fins, and 18- by 18-in. orifices on the floor, were satisfactory. Discharges of 66.0 and 69.7 cfs produced heads of 10.0 and 12.0 in. on the weirs. With standard orifices in all weirs, heads of 12.2 and 13.4 in. on the first weir below the fish counting station were required to provide the above discharges. (Modified author abstract).