Posted on February 10, 2022
EUGENE, Ore. — Army water managers will delay refilling Cougar and Fall Creek reservoirs and conduct spill operations at Foster Dam as required by the U.S. District Court for the District of Oregon’s Willamette Valley injunction because of recent litigation. The delay at Cougar and Fall Creek will impact the U.S. Army Corps of Engineers’ (Corps) ability to refill the reservoirs to their normal summer levels, which will impact boating and recreation activities.
However, because annual water year forecasts have high variability, it will be difficult to predict with certainty all potential impacts until later in the spring. Corps officials are aware of the potential affects to recreation visitors and will work to share information as limitations to access and use of reservoirs becomes clearer.
“Every year, we strive to meet the public’s expectations surrounding water availability within the Willamette Valley System of reservoirs during the summer,” said Erik Petersen, operations project manager. “There are and will always be constraints on how we manage water. People can look to last year’s drought and several challenging water years over the last couple of decades to see some of the difficulties we face. However, we must find ways to protect threatened fish species if we want to continue enjoying the other benefits these dams provide and will absolutely align with the intent and direction of the court.”
Fall Creek: The Corps will hold Fall Creek Reservoir, 22 miles southeast of Eugene, to 700 ft. above sea level until mid-March and then refill and hold at 728 ft. through May. This may eliminate use of two boat ramps for use, Cascara and Winberry; however, North Shore may be available. Corps staff is unsure of how that will impact camping opportunities.
Cougar: Corps water managers will not substantially refill Cougar, 50 miles east of Eugene, until May 1, attempting to reach 1,571 ft. by July 1; however, no boat ramps will be available at that reservoir elevation, and typically, precipitation available to refill after that date is minimal.
Foster: The Corps will use spillways to release water for fish passage and maintain a reservoir elevation of 613 ft. until early April at Foster Dam in Sweet Home, Ore., which is below the elevation of two boat ramps: Calkins Park and Gedney. By May 11, the Corps plans to have lake levels up to 637 ft. by using water from Green Peter Reservoir, a few miles northeast of Sweet Home. While this is a consistent operation as in years past, Foster refill will be a little later than normal, and that could impact water levels at Green Peter, depending on the rest of the refill season.
Low water levels may make boating more hazardous, so boaters should take extra precaution and always wear a life jacket.
Background: Generally, Portland District begins storage reservoir refill in February and it ends in late May. The 13 Willamette Valley reservoirs support a variety of purposes, most notably flood risk management, fish and wildlife, water quality, hydropower generation and recreation. The reservoirs are kept at a lower level in the winter to reduce downstream flooding and are refilled in the spring in preparation for the conservation season, where water upstream is used for recreation and downstream is used to maintain adequate summertime flows in the rivers for fish, water quality and irrigation. It is important to note that the Willamette Valley is primarily a rain-driven system rather than a predominantly snow-melt system, as is common with other Northwest reservoirs.
