Fish Tale

Fish Tale

The Bonneville Dam, which spans the Columbia River between the U.S. states of Oregon and Washington, has affected fish populations, but now organizations are attempting to lessen its impact on the environment.


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Earth Science, Engineering, Geography, Physical Geography, Physics

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The Columbia River, which runs through the states of Oregon and Washington and the Canadian province of British Columbia, was once full of wild white water and large salmon populations.

Now, the 1,954-kilometer (1,214-mile) river has been domesticated. Bridges seem to have tamed it, like saddles on horses. More importantly, a series of dams and locks have chopped the once mighty Columbia into a series of calm reservoirs.

The first major artificial change to the Columbia River occurred in 1938, with the completion of the Bonneville Dam. The Bonneville Dam is actually a series of several dams and links Oregon and Washington. Located in the Columbia River Gorge National Scenic Area, Bonneville Dam was built for two reasons: to provide residents of the Pacific Northwest with electricity and to make the waterway easier for boats to navigate.

Other dams were built along the course of the Columbia, including the massive Grand Coulee Dam in Washington, which became the largest concrete structure in the United States. As of 2022, there are 14 major dams on the main stem of the Columbia River.

The dams on the Columbia and the streams that branch off from it account for about 50 percent to 65 percent of the area's electricity generation. They produce that power using less coal and natural gas than other forms of power generation. The artificial structures also make it possible for barges and boats to travel 750 kilometers (465 miles) along the Columbia, from the Pacific Ocean all the way to Lewiston, Idaho. That's because the Columbia River connects with the Snake River in eastern Washington.

Salmon Runs

Despite the benefits to human residents in the area, the dams have caused trouble for the river's ecosystem, especially the Columbia's salmon. Jeff Hickman is a hunter and former organizer for the Oregon chapter of the Sierra Club, an environmental organization. He says that it's hard to determine exactly how many salmon were in the river before the construction of the dams. Records were not taken until after the structures were already in place.

"The Columbia River historically was the most healthy watershed," Hickman says. "It had the largest population of fish on the planet."

The dams transformed the Columbia from a fast-moving waterway to what is basically a handful of reservoirs with slower currents and warmer water. Hickman says the warmer temperature puts more stress on migrating fish. It also creates a more suitable environment for predators that eat the fish native to the Columbia.

Bob Heinith is a program coordinator for the Columbia River Inter-Tribal Fish Commission, an organization that represents the region's Native American population. According to Heinith, the dams have hurt fish habitats. He says dams have cut off access to upstream areas, which has destroyed about two-thirds of the overall habitat for fish.

Fish Ladders

At all of the government-owned dams, except for Chief Joseph and Grand Coulee, fish ladders were constructed. These allow adult salmon to bypass the structures and continue upstream to lay eggs. The fish ladders are like stair steps that water flows down, creating a series of shallow waterfalls. While dams often prove to be impassable for the fish, the salmon are able to get upstream using these fish ladders.

When the dams were constructed, the people planning them thought about how the adult fish needed to swim upriver to lay eggs. Not much thought was initially given to the juvenile fish that head downstream toward the ocean, though.

The Bonneville Power Administration distributes the electricity generated from the dams. It has implemented several methods to assist the juvenile fishes' journey downstream. The dams' turbines have been redesigned so that they are less of a hazard to juvenile fish passing through. The administration also added a path that allows the fish to swim around the turbines entirely.

A process known as spilling seems to help the fish, too. During salmon migrations, water is spilled over the dams to imitate the river's former flow. The dams generate less power, but this approach is better for the fish.

Sea Lions

Over the last six years, a new problem has emerged.

Sea lions have learned that they can travel from the Pacific Ocean up the Columbia River. At the base of Bonneville Dam, they can dine on all the salmon that congregate there before attempting to bypass the structure. To combat the problem, the National Marine Fisheries Service gave permission to the U.S. Army Corps of Engineers and the states of Washington and Oregon to scare away the marine mammals with firecrackers or rubber bullets. The states have even begun the questionable process of euthanizing, or humanely killing, repeat offenders.

Michael Milstein is a former Bonneville Power Administration public affairs officer and current NOAA Fisheries public affairs officer. He says that over the years, the dams have been changed significantly in an attempt to lessen their impact on the river's ecosystem.

"They are really different dams than they were when they were first built in terms of the way they affect fish," Milstein says.

The Sierra Club notes that the Bonneville Power Administration's efforts have yielded some results, but they wonder if the dams are worth all the extra time and money.

"There's no doubt it's helping, but you have to weigh out the costs," Hickman says.

Fast Fact

Fish Cam
See what fish are swimming through the Bonneville Dam. The Bonneville Dam Fish Camera updates with a new photo every 20 seconds.

Fast Fact

River Writer
During the 1930s, American singer and songwriter Woody Guthrie was hired by the Bonneville Power Administration to write songs promoting the hydroelectric dams on the Columbia River. During the month-long job, he penned classics including "Roll On Columbia," "Grand Coulee Dam," and "Pastures of Plenty."

Media Credits

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Stuart Thornton
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
National Geographic Society
Last Updated

October 19, 2023

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