Columbia & Snake River Dams

The impact of dams on the Columbia River Basin is profound. The electric power generated supplies industry and homes throughout the region and is sold beyond the Northwest. Irrigation from the waters of the Columbia system makes agriculture possible in many areas of the largely desert basin. The system of locks that accompany the dams make the Columbia a major transportation artery. And the salmon population has suffered greatly.

Writing in the late 1930s as the Grand Coulee and Booneville projects were coming online, future Oregon Senator Richard Nueberger predicted these mixed blessings from the dams:

The peril that Bonneville and Grand Coulee constitutes to the salmon industry has given the opponents of industrial power rates their most effective argument. What will happen to the grandeur and majesty of the West if its rivers are lined with factories? Now the Columbia is crystal-clear and ice cold. Sewage and waste material do not contaminate its rush of white water. Indian fishermen and forest rangers can scoop up its drops and drink them without fear of typhoid or other water-bourne diseases. The river is full of oxygen, and the fish coming upstream have a maximum of energy to thrash their way to their mountain spawning grounds.

The system has grown considerably beyond the Bonneville and Grand Coulee projects as you will discover in the map.

Major power generating dams on the Columbia and Snake Rivers date back over a century. Open the map to become familiar with the size, location, and power generating capacity of these dams. Information about each dam is provided both in individual popups and as part of the table you can access in the Dams layer. Use this information to complete the Timeline worksheet.
Columbia River Dams

To Start You Thinking

1) The Dams layer includes a time slider. Click thru the years since 1904 and examine the progress of dam construction along the Columbia River system. What are the oldest dams in the system and where are they located? the newest? When were the largest dams in the system built?

2) Zoom in on the four lower Snake River dams between Lewiston, Idaho and Kenniwick, Washington. Calculate the total power generating capacity of these four dams and determine what percent the total is of the cumulative power capacity determined in the worksheet.

3) One of the most obvious features of dams is to control the flow of water and, as a result, to change the character of a river. The Columbia River dams are no exception. The before and after images below give you a sense of the change. Explore the river between the dams listed in the map and through the pictures. Use the Elevation provided in the map popup for each of the dams in the table below, measure the distance between the dams, and calculate the river's gradient - the number of feet per mile that it drops - between each of the pairs of dams.

River between Before After Gradient
Priest Rapid Dam & Wanapum Dam a a  
Bonneville Dam & The Dalles Dam a a  
    Click images to enlarge  

4) The surface character of the river has certainly changed as a result of the dams. Below the surface, however, the past lingers. The pair of photos below show Celilo Falls, just upriver from the Dalles Dam. The falls were flooded in 1957 with the completion of the dam destroying the native fishing site pictured at the left. The photo on the right is a sonar image of the same site taken in 2008. Rumors persisted for years that the falls were dynamited and destroyed at the time of the flooding. Describe what the photos suggest.

a a
Click images to enlarge

5) The perceptions that different communities of interest had and have regarding the dams on the Columbia vary as these two quotations suggest:

Elizabeth Woody - Historically, the Wyampum lived at Wyam [native village on the south side of the falls] for over twelve thousand years. Estimates vary, but Wyam is among the longest continuously inhabited communities in North America. The elders tell us we have been here from time immemorial. 1

Today we know Celilo Falls as more than a lost landmark. It was a place as revered as one's own mother. The story of Wyam's life is the story of the salmon, and of my own ancestry. I live with the forty-two year absence and silence of Celilo Falls, much as an orphan lives hearing of the kindness and greatness of his or her mother.


Woody Gutherie - Uncle Sam took up the challenge in the year of 'thirty-three,
For the farmer and the factory and all of you and me,
He said, "Roll along, Columbia, you can ramble to the sea,
But river, while you're rambling, you can do some work for me.2


Describe and compare the values regarding the river implied in each of these quotes.

6) Use the graph tool below to explore the passage of chinook and sockeye salmon and steelhead through each of the major dams on the Lower Columbia and Snake Rivers. Describe any general patterns that you observe.

Graph Fish Count -
Dam: Fish:


1 Elizabeth Woody, "Recalling Celilo," , 1999 at Salmon Nation.

2Woodie Guthrie, "Grand Coulee Dam," , 1941 as found at Woodie Guthrie.

James W. Troup, The John Gates at Priest Rapids, 1884, available at Wikimedia Commons

Steamboat Hassalo Running Cascades Rapids ,1888, available at Wikimedia Commons

Men fishing at Celilo Falls on the Columbia River, 1950, from Oregon State University Library, #17070105

U.S. Army Corp of Engineers,Celilo Falls - Sonar Image, 2007

Fish count data by dam from Adult Salmonid Passage, Columbia River DART (Data Access in Real Time) Project downloaded in February, 2012.

Last modified in November, 2021 by Rick Thomas