News Release
| Release Number: | 02-059 |
| Dated: | 3/28/2002 |
| Contact: | Matt Rabe, 503-808-4510 |
Portland, Ore.-Despite the need to increase outflows from some of its Willamette Valley Basin reservoirs, the U.S. Army Corps of Engineers still believes the reservoirs will fill in time for the summer recreation season.
Beginning on Friday, March 29, the Corps will adjust releases from its reservoirs to ensure that flows in the main stem of the Willamette River stay above levels needed to maintain healthy populations of salmon, steelhead, and other fish species. The flows were requested by the Oregon Water Resources Department, Oregon Department of Fish and Wildlife and National Marine Fisheries Service, said Matt Rea, Corps coordinator for the Willamette Valley reservoirs. "We are helping out with the annual spring chinook salmon and winter steelhead migration," Rea said. "The juvenile fish are moving downriver and the adults are beginning to return. These fish migrate during natural high spring flows. Since 1999 we have adjusted our April and May reservoir operations to ensure that there are adequate flows to protect the fish."
The minimum flow targets as measured at Salem are 20,500 cubic feet per second (cfs) beginning on April 1. Although flows at Salem measured about 26,000 cfs on March 27, they are falling rapidly. With short-term forecasts predicting fair weather with little or no precipitation, natural river flows are expected to continue to drop. The Corps will increase reservoir releases to make up the difference.
According to Rea, the routine changes are not expected to affect the Corps' ability to store enough rain and snowmelt to have full pools in the reservoirs for the summer recreation season. "Our minimum main stem target flows fall to 16,500 cfs by April 15. In addition, basinwide, the snowpack is about 147 percent of normal," Rea said. "We're still confident we'll fill despite the increased releases," especially at Detroit Reservoir, which never filled last year. This year, boating facilities at Detroit, including marinas, are expected to be usable by mid- to late-April. Boating access to the Detroit reservoir currently is available from Oregon State Park's Mongold boat ramp.
To meet the required flows, the Corps will increase releases from six reservoirs and decrease them at three. The greatest increases will likely occur at Hills Creek, Green Peter and Foster dams, while other projects will be adjusting flows slightly depending on weather conditions and inflows. Cottage Grove, Blue River, and Detroit dams also will increase releases. Releases are adjusted very gradually, thus no safety hazards are expected. Changes in water levels may be noticeable downstream of some of the projects, however.
The expected change at Big Cliff Dam (a small reregulating dam that controls releases from Detroit Lake) is from the current 1,000 cubic feet per second (cfs) up to about 1,500 cfs. These flows will vary depending on the weather, however. Either an increase in precipitation or warmer weather, which causes the snowpack to melt more rapidly, would be expected to increase natural streamflows.
Beginning Monday, April 1, water releases will increase from Foster Dam in an effort to lower the reservoir so crews can install a weir in one of the dam's spillway gates. The operation, which takes place every year at this time, is designed to help migrating winter steelhead move past the dam on the journey to the Pacific Ocean. The reservoir will be refilled by the Memorial Day weekend.
The Corps coordinates a delicate balancing act when managing its multiple purpose projects. In the summer, two of the primary competing needs are recreation and fisheries. In addition, other authorized purposes of Corps projects include flood damage reduction, hydroelectric power production, irrigation, navigation and municipal and industrial needs.