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.


3 - 12


Earth Science, Engineering, Geography, Physical Geography, Physics

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The Columbia River used to be a wild waterway full of frothing white water and robust salmon populations.

Now, the 1,954-kilometer (1,214-mile) river has been domesticated: Bridges seem to clamp down on the Columbia like yokes and, more importantly, a series of dams and locks has chopped the once mighty Columbia into a series of placid 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 the states of 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 more navigable for boat traffic.

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 its tributaries account for about 50 to 65 percent of the area’s electricity generation, and they produce the power using less coal and natural gas than other power generators. The artificial structures also make it possible for barges and boats to travel 750 kilometers (465 miles) up the Columbia River, from the Pacific Ocean all the way to Lewiston, Idaho.

Salmon Runs

Despite the benefits to human residents in the area, the dams have wreaked havoc on the river’s ecosystem, especially the Columbia’s salmon. Jeff Hickman, hunter and former organizer for the Oregon chapter of the Sierra Club, says that it’s hard to determine exactly how many salmon were in the river before the construction of the dams, because 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.

“That water temperature not only puts more stress on migrating fish, traveling fish, but also makes a more suitable environment for predatory, invasive fish such as smallmouth bass and walleye and native fish such as the northern pike minnow, which is commonly called the squaw fish,” Hickman says.

Bob Heinith is the hydro 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 destroyed fish habitats.

“We’ve lost about two-thirds of the overall habitat for fish by large storage dams that have cut off passage to upstream areas,” Heinith says.

Fish Ladders

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

Though the adult fishes’ journeys upriver to spawn were taken into account when the dams were built, little thought was initially given to the juvenile fish that head downstream toward the ocean.

The Bonneville Power Administration, which distributes electricity, has implemented several methods to assist the juvenile fishes’ journey downstream. The damsturbines have been redesigned so that they are less of a hazard to juvenile fish passing through. Another improvement at Bonneville Dam is a sluiceway that takes the fish away from the turbines entirely and delivers them to the river two miles downstream.

Heinith believes there is one effort by the Bonneville Power Administration that appears to work better than the organization’s other projects. It’s a process known as spilling. During salmon migrations, water is spilled over the dams to imitate the river’s former flow.

“What we’ve seen that is the most effective is spilling, spilling over the dams,” he says. “Of course, that’s in direct conflict with power generation.”

Sea Lions

Over the last six years, a new problem has emerged for the Bonneville Power Administration and the U.S. Army Corps of Engineers, which owns and operates Bonneville Dam.

Sea lions have learned that they can travel from the Pacific Ocean all the way up the Columbia River to the base of Bonneville Dam, where 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 controversial process of euthanizing, or humanely killing, repeat offenders.

Michael Milstein, a former Bonneville Power Administration public affairs officer and current NOAA Fisheries public affairs officer, 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 have to 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. “If it costs this much to operate the dam at a legal level to comply with maintaining or enhancing fish runs, then how much are you gaining by having the dams in place? How much is it benefiting us by hydroelectric-powered barge navigation? Sometimes, those cause and effects don’t weigh out.”

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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