Oct 23, 2024

Klamath River Salmon Return to Tributaries after Dam Removals

With four dams removed, Klamath tributaries are once again free-flowing streams allowing easy access for Pacific salmon to spawn. (USFWS)

The first salmon have shown up above where four dams once obstructed the Klamath River, causing plenty of excitement among anglers, conservationists and Native Americans

The Klamath, stretching from northern California into southern Oregon, was once the third-largest salmon river on the West Coast. However, the construction of four PacifiCorp hydroelectric dams over the 20th century significantly disrupted the river's ecosystem and decimated its salmon populations.

The dams, primarily used for power generation, blocked salmon from accessing hundreds of miles of spawning habitat. The resulting stagnant water conditions promoted algae growth, deteriorating water quality, and increased water temperatures, all of which are detrimental to salmon survival. 

Additionally, the dams created concentrated areas where fish congregated, making them more susceptible to diseases. One of the largest observed die-offs of adult Pacific salmon ever occurred below the lower dam in 2002, with an estimated 60,000 fish perishing, per the U.S. Fish & Wildlife Service.

The most significant impacts of the dams was the complete cutoff of salmon migration into the Upper Klamath Basin. The Copco #1 Dam, completed in 1918, effectively blocked salmon from reaching many miles of tributary spawning habitat in Oregon. 

This is the first salmon observed upstream from the point where the aging dams blocked the Klamath headwaters--many more have returned since. (USFWS)

This devastating loss of habitat had a profound effect on both the river's ecology and the communities that depended on it. Salmon production slumped, and with it the fishing both downriver and in the coastal Pacific where the fish went to feed and mature before eventually returning in an attempt to spawn in their natal streams.

By the 1970s, the negative consequences of the dams became increasingly apparent. Public awareness of environmental issues led to the designation of the river below the Iron Gate Dam as a National Wild & Scenic River, but this designation came too late to reverse the damage caused by the dams.

The aging dams, some now over a century old, were in need of costly repairs or replacement. Recognizing the urgent need for restoration, efforts were initiated to remove the dams and restore the Klamath River's salmon populations. The last dam was removed in August of this year, funded by state and federal agencies.

There’s currently a lot of excitement among fishery managers as well as the area Native Americans who used to rely on the salmon runs, because the first spawning salmon (and by now many others) have been seen in the tributaries above the location of Copco #1. 

While a few spawning salmon may seem a drop in the bucket, a successful spawn of a few dozen fish can repopulate with tens of thousands of fry where survival is good. Within a few years these fish should be entering the fishery off the coast. Depending on species, the first adults might return in their own spawning run in as little as 2 years. Kings, the largest salmon, take around 8 years to make their run.

Though what was lake bottom looks like a muddy wasteland now, it will soon be covered in new growth, researchers say, and the upper river will again support lots of spawning salmon. (USFWS)

Clearly, the removal of these dams—which seemed like an over-the-top idea at first--represents a significant step towards recovery of this once great fishery.

It will be good for anglers, for commercial fishers and for the First People, including the eponymous Klamath, who have claimed cultural and spiritual connections to the run as well as the obvious commercial/subsistence benefits.

It’s not likely that the success with the Klamath will result in a rush to get rid of other larger and more valuable dams—like those giant facilities on the main-stem Columbia River—in the near future; the economics don’t make sense. 

But it does appear that some dams on the lower Snake River might be on their way out, as well as those on the Elwha and on Columbia tributaries including the White Salmon and the Methow. The success on the Klamath will accelerate these plans.

Pacific Coast salmon fishing will never be what it was before the first dam was built or the first tree cut down on the watersheds, but dam removal does, in fact, seem to be one great step in the right direction.

— Frank Sargeant
Frankmako1@gmail.com