Spring Chinook: Nineteen Isn't Enough

The Deschutes River Alliance continues to push Portland General Electric to alter operations of its Selective Water Withdrawal Tower. In our most recent blog, we urged advocates of a healthy lower river to get behind the “Night Blend” scenario, a mix of the maximum amount (60 percent of the outflow) of cold water from the depths of Lake Billy Chinook, with 40 percent surface water. The best available science tells us the lower Deschutes River needs all the cooler, cleaner water it can get. The Night Blend is simply the most expedient route to get there. It would mean a better Deschutes now, not at some far-off future date. Yet support for this change from PGE is lagging, in spite of the lack of a more effective alternative.  

Without an adequate level of scrutiny, some Deschutes River advocates claim that the best path forward for the lower Deschutes will be to go all in for dam removal–which can’t occur before PGE’s license for its Pelton-Round Butte complex expires in 2055. From both a policy and science perspective, this strategy looks like a loser.

On the policy side, if these would-be dam busters are serious about getting rid of the three dams that comprise the Pelton-Round Butte Complex, they’d better get moving. Dam removal is a long-term campaign. On the Elwha River in Washington, it took thirty years from the time the lower Klallam Tribe formally proposed removing Glines Canyon and Elwha Dams until that river ran free in 2014. And the four dams currently being demolished on the Klamath: the campaign took 22 years to begin chipping out concrete, even with the dam’s owners, Pacific Power, on board with the plan to rid itself of these stranded assets. 

From a science perspective, firing off a dam removal campaign without taking steps to make sure salmon can survive in the interim would make freeing the lower Deschutes a moot point. Already, anadromous fish in the Deschutes Basin are in trouble. The U.S. Fish and Wildlife Service office in Vancouver has closely tracked returns of salmon and steelhead in the Deschutes since 1977. The current trend, gleaned from numbers furnished by the USFWS, indicates these fish have only years, not decades to spare. Spring chinook numbers have dwindled to such disturbingly low numbers that extinction now looks more likely than survival–unless significant changes are made in the very near future. The decline of springers in the Deschutes correlates with tower operations. Ceratonova shasta is a parasite that kills spring Chinook via spores that when released into the water column from tiny polychaete worms infect Chinook on contact. Prior to tower operations, C. shasta was present in the Deschutes, but in very low numbers. Post tower operations have fostered a deadly, manifold increase of this parasite at levels presumptive for infection.

"a dam removal campaign without taking steps to make sure salmon can survivein the interim would make freeing the lower Deschutes a moot point."

A widely accepted benchmark for the viability of any salmon population is three hundred individuals. Springers in the Deschutes have not met this minimum number for the past six years. In 2023, just 19 “project origin” (springers marked at the Round Butte hatchery) returned. 

Above graph: post Selective Water Withdrawal Tower returns of Chinook on the Deschutes River, 2012-2022. The red line indicates the goal of 1,000 fish annually.

The quarry most coveted by anglers on the lower Deschutes is wild steelhead. As the graph below indicates, the current trend line is headed toward zero. Don’t panic: this doesn’t mean there will be no wild steelhead in the river next year. But it does mean that if the current trend continues, there won’t be enough wild steelhead in future years to maintain the species in perpetuity. The life cycle of wild steelhead, in which one to four years is spent in a freshwater environment, places a premium on a healthy Deschutes River. 

Above graph: post-SWW returns of wild steelhead to the lower Deschutes River. 

It’s often pointed out that Pacific salmon are in trouble throughout their range. But this trouble is exacerbated on the Deschutes by a management regime that puts warm, polluted water into the lower river eight months out of the year. The consequences of this dirtier water have been a wide range of ecological impairments from the loss of sensitive aquatic insects, drop in song bird and swallow numbers along the river, to the declining population trends for salmon and steelhead, all of which affirm this stark reality.

The good news is there’s still time, and that the fix could be quick. The Night Blend scenario is highlighted in PGE’s own 2019 water quality report as a practical way of balancing the needs of fish with the many other demands placed on the Deschutes. The only thing keeping the fish from getting a fair shake–now, not 30 years from now–is a more urgent, vocal, insistent call by the thousands of people who love the river.