Work on Alcova dam to begin in October
MILLS, Wyo. (Press Release) -The Wyoming Area Office of the Bureau of Reclamation is preparing for contract construction work at Alcova Dam following the 2020 irrigation season. To accommodate the construction work, the reservoir will be temporarily lowered an additional 29 feet below the normal winter operating elevation of 5,488 feet, down to an elevation of 5,459 feet, which is below the level of the spillway crest.
“Completion of this project is important in order to ensure the continued reliability of the spillway structure,” said Wyoming Area Manager, Carlie Ronca. “It includes replacing deteriorated concrete on the downstream spillway and stilling basin retaining walls, retaining wall caps, and floor slabs in designated areas. Additionally, it will replace downstream spillway and stilling basin handrails and chain-link fence.”
Summer reservoir levels will not be affected and will remain at normal levels through the end of September. Spillway and stilling basin access work will start after Oct. 1 and is scheduled to be completed by March 31, 2021 to avoid peak spillway discharge season. During the month of October, Alcova Reservoir will be lowered 39 feet at an average rate of about 15 inches per day. In a normal year, the reservoir is lowered about 5 inches per day for a total of 10 feet.
The flows below Alcova and Gray Reef Dams during October will average 2100 cubic feet per second (cfs) through Oct. 20, and then be reduced to the normal winter flow rate of 500 cfs. Alcova Reservoir is planned to be refilled to normal winter operating elevation in the last half of December. This will result in temporary higher than normal releases through the Miracle Mile and Pathfinder Dam, and minor declines in reservoir levels in Seminoe and Pathfinder Reservoirs. By Jan. 1, 2021, Alcova Reservoir will be restored to its normal winter operating range.
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