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  Water control   Water control
The once free-flowing Columbia is now largely a series of reservoirs.


  • Stable water levels enable cargo ships to navigate the river far upstream, providing inland farmers with relatively low-cost shipping.

  • Thanks to epic, reservoir-fed irrigation projects, vast swaths of the Columbia Plateau have gone from barren to bountiful.

  • The reservoir system has saved the Columbia River Basin from the threat of flooding. In 1948, before the current storage plan was in place, a Columbia River flood destroyed Vanport, Oregon, then a town of about 17,000 people.


  • The slow current extends the time it takes for juvenile salmon to reach the Pacific—offering salmon predators a wider window of opportunity.

  • The pooling of river water allows it to heat up, which increases salmon mortality, partly due to the growing populations of salmon predators that are adapted to warmer waters.

  • Reservoirs have flooded gravel bars where salmon reproduce.

  • U.S. taxpayers heavily subsidize the irrigation systems that make farming in arid eastern Washington and Oregon possible.

  Shipping   Shipping
With water levels tamed by damming, barges can navigate far upstream.


  • Relatively inexpensive, Columbia River Basin barge shipping eases economic pressures on farmers as far inland as Montana and the Dakotas.

  • Each year the reservoir system allows barges to carry 17 million tons of cargo along the Columbia River and its tributary the Snake River.

  • The National Marine Fisheries Service and the Army Corps of Engineers use water-filled barges to ship more than half of all juvenile salmon and steelhead smolts in the Snake River past dams, then release the fish near the mouth of the Columbia.


  • The dams that made much of the Columbia River system safe for shipping have done so at the expense of salmon runs—and those who depend on them. The region’s economy is losing 500 billion dollars a year due to salmon decline.

  Dam structures   Dam structures
As water surges through the massive turbines of a Columbia River dam, electricity is created and salmon often are injured.


  • Dams in the Pacific Northwest generate half the electricity in the region—largely pollution free.

  • The 29 dams of the Columbia Basin’s federal hydropower system have enabled Northwesterners to purchase electricity at half the average U.S. price.

  • The inexpensive electricity generated by dams has lured heavy industry to the Northwest.
  • Cons

    • As barriers to salmon migration, dams are largely responsible for the decline of Columbia River stocks to about one to two percent of their historical numbers. Today eight stocks of Columbia salmon and steelhead are on the U.S. endangered species list.

    • As smolts migrate to sea, they are often forced through dams at high pressure and their swim bladders often burst. Each Columbia River dam and reservoir kills an estimated 8 to 10 percent of migrating smolts.

    • Though most Columbia dams have fish ladders (wide concrete waterways that guide them over), critics contend that ascending them may leave salmon too exhausted to procreate. Grand Coulee Dam has no fish ladder—its mile-wide (1.6-kilometer-wide) wall eliminates 600 miles (966 kilometers) of Columbia River salmon habitat.

    • Though spillways designed to guide smolts around turbines do help them reach the Pacific faster, the spilling water can saturate water with nitrogen, which is harmful to fish.

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