News Release
| Release Number: | 02-141 |
| Dated: | 8/22/2002 |
| Contact: | Public Affairs Office, 503-808-4510 |
Portland, Ore.-On Aug. 28, the U.S. Army Corps of Engineers will begin operating the reservoir behind Bonneville Dam to within 1.5 feet of the normal full pool to accommodate tribal requests. Under normal conditions, the reservoir's operating range could fluctuate up to 5 feet.
Providing a high and stable pool for tribal fishing at Bonneville Dam, located 40 miles east of Portland, is a priority during the treaty-fishing season, said Cathy Hlebechuk, acting chief of the Corps Reservoir Control Center. The agency is working with other river users to minimize potential impacts that could be caused because of this specialized reservoir operation. The treaty fishing season may be extended until mid-September, depending on the amount of fish harvested.
To meet regional power generation needs, however, reservoir levels at The Dalles Dam need the flexibility to fluctuate up to 3 feet on a weekly basis, said Hlebechuk. The reservoir behind John Day is generally kept within a 1.5 foot operating range to ensure stable flows for fish and to maintain safe conditions for operating irrigation pumps.
Since the demand for power increases in the morning and evening, more water must be sent through generating turbines at the dams at those times, lowering reservoir levels. At night, when demand for power eases, less water is sent through the generating turbines, and reservoir levels rise. When the Bonneville pool is kept steady during the treaty-fishing season, reservoir level flexibility at The Dalles helps compensate for Bonneville Dam's steady level.