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|Title:||Model study of spillway, Allatoona Dam, Etowah River, Georgia|
|Authors:||United States. Mississippi River Commission.|
U.S. Army Engineer Waterways Experiment Station.
Allatoona Dam, Ga.
|Publisher:||U.S. Army Engineer Waterways Experiment Station.|
Engineer Research and Development Center (U.S.)
Synopsis: This memorandum constitutes the final comprehensive report on the model study performed at the U. S. Waterways Experiment Station of the spillway for the Allatoona Dam, Etowah River, Georgia. This study was authorized by the Chief of Engineers on 1 January 1942. The general purpose of the tests was to investigate the hydraulic performance of the proposed structures, to develop means of correcting any uneconomic or undesirable conditions found to exist, and to investigate the effect of the tail-race excavation on tail-water elevation. All tests were conducted on a model built to the linear-scale ratio, model to prototype, of 1 to 50. The Allatoona dam, a flood-control and hydroelectric power project of the Alabama-Coosa River system, will be of the concrete-gravity type, curved in plan with the spillway in the center. The spillway will be surmounted by nine tainter and two regulating gates, and is designed to pass a flow of 297,000 cfs under a head of 33.8 ft. Principal findings of the model study were as follows: a.The performance of the spillway weir of original design proved satisfactory. b.The tailrace excavation effected a lowering of the water-surface at U.S.E.D. gage 3 of 4.65 ft at a discharge of 1,000 cfs and 2.05 ft at the maximum power discharge of 15,000 cfs. c.A stilling basin at elevation 690 proved satisfactory, although action within the basin was more turbulent than in the basins at lower elevations. A 15-ft end sill having a vertical upstream face was necessary to prevent the hydraulic jump from being swept from the basin at the maximum discharge. A small secondary sill was necessary for the protection of the river bed at low flows. d.The use of baffle piers as a means of dissipating energy in the basin at elevation 690 was not successful. e.With discharges controlled by crest-gate operation, flow was more satisfactory in the stilling basin if the gates were operated so that flow was distributed across the spillway rather than being concentrated in the center. f.The left training wall extension downstream from the stilling basin could be shortened and lowered without interference to basin action or flow below the powerhouse. This wall change alone was sufficient to effect a saving of about $20,000 which was enough to offset the cost of the model study.
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|WES-Technical-Memorandum-No.214-1.pdf||12.11 MB||Adobe PDF|