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Pacific Northwest Region
Boise, Idaho
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John Redding
(208) 378-5212
Karl Ames
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Released On: August 18, 2004

Powder River Flows to Vary During Test
The Bureau of Reclamation and the Baker Valley Irrigation District will be testing the water flow deflector within Mason Dam's stilling basin on August 30 to September 1, which will result in river flow fluctuation. Mason Dam is located on the Powder River about 17 miles southwest of Baker City, Oregon.

The deflector will be tested at various flow rates, requiring the discharges from the dam to fluctuate between a minimum flow of 10 cubic feet per second and a maximum flow of 450 cfs. The river water level in the Powder River is expected to fluctuate up to 2.5 feet at Baker City, Oregon.

The device, which was installed in October 2002, is designed to control high speed water flows emitted from the outlet tubes at the base of the dam. The flow deflector was developed by Reclamation engineers and designed to protect the outlet work's stilling basin floor from damage.

Erosion is caused when the rapidly cycling water within the basin tosses the debris violently against the floor. The deflector redirects the water to prevent debris from entering the basin, thereby preventing erosion.

"Reclamation engineers believe the device will eliminate or reduce costly repair of the stilling basin," said Manager Jerrold Gregg, of Reclamation's Snake River Area Office. "The stilling basin at Mason Dam is common to many Reclamation built facilities. If successful, the deflector, custom designed to this basin, will be widely used within the agency."

Mason Dam is an earthfill structure completed in 1968 and owned by Reclamation. The facility is operated by the Baker Valley Irrigation District of Baker City, Oregon.

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Reclamation is the largest wholesale water supplier and the second largest producer of hydroelectric power in the United States, with operations and facilities in the 17 Western States. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at www.usbr.gov.