The Story

Faces of Restoration: The Cougar Tower is the story of the extraordinary collaboration of biologists, The US Army Corps of Engineers, construction workers and Oregonians for the sake of restoring wild fish habitats of the South Fork of the McKenzie River.  Oregon has some of the most environmentally diverse and beautiful landscapes throughout the United States of America.  Among the most beautiful of Mother Nature’s gifts to Oregon are the rivers McKenzie and Willamette, which gracefully meander through and underneath our cities throughout the state.  Our rivers spawn incredibly diverse landscapes that provide habitat for one of our most prized possessions: our plentiful salmon population, which draws anglers from around the world as a premiere destination place for recreational fishing.  However, what if the salmon that grace our waters were to... disappear?  What would Oregon’s rivers, let alone the rivers throughout our country, look like without the very nature that defines it?

In waters throughout the Pacific Northwest, this very problem is not just a scenario – it’s reality. During the mid-thirties, residents of the Willamette Valley were tied of the seasonal flood waters intruding upon their cities.  The Army Corps of Engineers was put to work to design a remedy these problems.  They proposed a system of thirteen dams to regulate the Willamette River and its major tributaries.  One of the final projects to be completed was the Cougar Dam.  When the dam came online, it provided electricity through hydroelectric generation while protecting Oregonians from seasonal flooding.  After the construction of the dam was complete in 1963, it began to draw water from the depths of the reservoir and channel that water back into the McKenzie River.  However, as biologists soon discovered, the water temperatures moving through the South McKenzie were not habitable for native fish populations, leading to a dwindling of the once abundant fish habitat that had graced the river.  Native spring Chinook salmon suddenly were in an environment in which the waters composing their habitat were ice-cold, drawn from the depths of the Cougar Dam reservoir and leaving the river simply too cold for salmon.

In the late fall, when the reservoir was emptied in preparation for the winter flood-control season, warm water that had been near the surface of the reservoir in the summer would surge through the outlets and into the river (Register Guard).  This unseasonable warmth triggered premature hatching of any salmon eggs buried in the gravel over which the river flowed.  Fish fry emerged in November and December, when there was little insect life on which to feed, and thus, their survival rates were poor.

Fortunately on the upstream side of Cougar Dam, in the southern Willamette Valley and in the heart of the McKenzie River, a 350-foot-tall, $52 million concrete ray of hope is nearly complete, with hopes of revitalizing the very habitats nature needs to once again flow throughout our precious rivers.  The relevance of salmon in Oregon is obvious – they’re very important to us for food, recreation, commerce, and many other things.  “Fish and humans have coexisted in the Willamette Basin for thousands of years,” US Department of Fish and Wildlife Biologist Jeff Ziller says.  “They’re very important to us.  The temperature control project will allow us to increase the productivity of those fish, restoring habitat that has been lost due to our need for power and flood control.”

In the 1980’s, a plan was devised to correct and revitalize the habitat that formerly provided a livable environment to the salmon population of the McKenzie river: the Cougar Dam Temperature Control Tower.  Biologists noticed the degradation in fish habitat immediately after the dam’s construction, but due to litigation it took until 1980 for the problem to be addressed. Throughout the next two decades, The US Army Corps of Engineers and biologists from the Oregon Department of Fish and Wildlife worked to create what is now finally coming into completion: a 350 foot tall concrete tower that intakes water from the reservoir surface to maintain consistent temperatures downstream. Another benefit of the tower is that it will allow downstream passage for migratory fish. The fish ladder at Cougar Dam had been in places ince initial construction, but the cold waters below it kept the salmon from reaching the ladder.

The construction of the Cougar Tower is a phenomenal, first-of-its-kind effort to retrofit an existing intake tower to provide for temperature control.  Throughout the construction, workers were faced with incredible challenges, including the preparation and explosive removal of the 50-foot concrete plug that held back the McKenzie River.  The Corps spent two and a half years preparing for this “tunnel tap,” which was removed safely and successfully and emptied the reservoir into the McKenzie.  “We were confident, but this really was the second drawdown of a high head reservoir,” said George Miller, the project manager of the Cougar Temperature Control Tower project.  “This tunnel tap and removal of the plug was highly specialized: we had the best blasting consultants in the United States and Canada that gave us guidance on actually removing the plug.”  Construction workers worked with explosives again in removing the temporary cofferdam, which kept Cougar Reservoir out of the construction site as concrete placed on the tower dried.  Finally, construction workers’ greatest challenge was the heights.  “Whether you’re coming down or accessing through the man basket, it got your attention” says Larry See, the site manager of the project.  See had the amazing opportunity to see his workers doing amazing things that are impossible to put into words, but he had the assistance of his camera to provide the words for him.  “It’s hard to describe the project.  I had a digital camera, so I’m able to take pictures almost continuously or constantly throughout the day and throughout the project.  If I catch a worker or a crewman doing something amazing and I get that on camera, then I print copies for them and drop them in their truck.  And later they’ll say, ‘Larry, that’s just awesome, because there’s no way to describe this to my wife or kids, or dad or mom.’”

With this project the entire south fork of the McKenzie River will be home to spawning salmon. “The McKenzie River happens to be the last remaining stronghold in the entire Willamette basin for Spring Chinook Salmon and Bull Trout,” says Ziller.  “Being able to utilize the upper south fork of the McKenzie River for production for these fish will increase the effectiveness of those populations to exist over time.”  When the reservoir fills with seasonal rains in the winter and spring of 2005, the tower will be submerged, its foundation disappearing in the depths of Cougar Reservoir. As the tower disappears underwater, it is the hope of many that the lost native fish habitats will finally reappear and thrive once again.