News Release
| Release Number: | 00-047 |
| Dated: | 4/10/2000 |
| Contact: | Matt Rabe, 503-808-4510 |
Portland, Ore.— Seven reservoirs in the Willamette River Basin may not fill by Memorial Day. Because of lack of rain during the past few weeks, Fern Ridge and Cottage Grove reservoirs are not expected to fill completely this summer. Fern Ridge should be within about 1 foot of being full by late May and Cottage Grove to within 2 feet of being full by May 31, said the U.S. Army Corps of Engineers’ Portland District hydrologist Ron Mason.
The same weather conditions, paired with the National Marine Fisheries Service’s recommended minimum flows, have prompted the Corps to change water releases from several dams to support the passage of juvenile Upper Willamette Chinook salmon and Upper Willamette steelhead. The Corps plans to draw water from Cougar Reservoir on the South Fork of the McKenzie River, Lookout Point Reservoir on the Middle Fork of the Willamette River, Blue River Reservoir on the Blue River in the McKenzie River Basin and Green Peter Reservoir on the Middle Santiam River. These water releases will increase flows at Salem from the current level of about 16,000 cubic feet per second (cfs) to about 18,500 cfs. Consequently, it is doubtful Lookout Point, Cougar, Green Peter or Blue River reservoirs will be full by Memorial Day weekend, the official start of the recreation season.
Water levels in Foster Reservoir on the Middle Santiam River will be kept low through May 23 to pass wild juvenile fish. Regulators will then begin to fill it slowly but it will not be full by Memorial Day.
Water will not be drawn from Fern Ridge on the Long Tom River or Cottage Grove on the Coast Fork of the Willamette River.
All the remaining reservoirs in the Basin—Detroit, Big Cliff, Hills Creek, Dorena, Fall Creek and Dexter—are expected to be full by Memorial Day.
Cougar Reservoir may be lowered as much as 26 feet below its normal level but should be full by early June. The Slide Creek and Echo boat ramps should still be usable well past Labor Day.
If weather conditions remain the same, Lookout Point Reservoir may fill only to elevation 922 feet by mid-June—4 feet below full. In that case, the Hampton boat ramp use may be limited to June and early July, however, the Signal Point boat ramp on the north shore will be available all year.
Blue River Reservoir may be lowered by about 32 feet below its normal level in April to help increase the flows at Salem before refilling. Though the date it will refill is dependent on spring weather, it could fill by the end of June or fill to within 4 feet of being full during July and August. In either case, both the Lookout and Saddle Dam boat ramps should be usable well past Labor Day.
Green Peter Reservoir may be lowered by about 15 feet during April but should be full by mid-June.
"We want to let people know early about these changes so they can plan their summers accordingly," said the Corps’ Portland District Engineer Col. Randall Butler. "We realize these lakes are prime summer recreation spots. It’s frustrating for us to not be able to meet the needs of all our customers all the time…we are dependent on Mother Nature," he said.
The Corps cautions that, as the water goes down in each of the lakes, submerged debris and stumps create hazards for boaters and water-skiers.
The Corps will release additional water, above normal releases, from its projects between April 1 and June 30. Despite the additional flows, the 18,500-cfs flow still falls below the target of 21,500 cfs recommended by NMFS, Mason said.
The Corps decided to release 18,500 cfs after modeling a number of alternatives and considering other environmental factors. Analysis performed by Oregon Department of Fish and Wildlife suggests that during the spring more juvenile steelhead migrants die when mainstem Willamette River flow levels are below 15,000 cfs at Salem.
One of the other factors considered was the current water temperature, which should remain below mid-50 degrees Fahrenheit through mid-April—an optimum range for migrating juvenile Chinook salmon and steelhead, according to Corps fisheries biologist Chuck Willis.
Another consideration was the relative number of juvenile migrant salmon and steelhead passing through the lower Willamette River, which is thought to be low. The lack of gull foraging activity at Willamette Falls suggests that few juvenile fish are passing the Falls at this time, Willis said.
In addition, the decision to release only 18,500 cfs during the first two weeks of April reduces the risk of too little water in the reservoirs to meet NMFS’ target flows later, Willis said. The Corps’ flow strategy was developed so the subsequent recommended flows of 18,500 cfs between April 16-30; 15,000 cfs between May 1-31; 12,500 cfs between June 1-15 and 8,500 cfs between June 16-30 could be met.
The Corps coordinates a delicate balancing act when managing its multiple purpose projects. In the summer, two of the most prevalent competing needs are recreation and fisheries.
"Our goal is to continue to operate the projects in the Willamette Basin in a balanced manner to address the multiple purposes for which they were authorized," Mason said.
In addition to fisheries and recreation, other authorized purposes the Corps balances include flood damage reduction, hydroelectric power production, irrigation, navigation and municipal and industrial needs.