Go with the Flow

Healthy Flows, Healthy Rivers

Learn how changing flows from dams can produce benefits for people and nature.


The natural flow of rivers and streams is critical to the health and viability of freshwater ecosystems and the fish and wildlife they sustain. At the same time, Oregon’s rivers and streams provide drinking water for human communities.

The Nature Conservancy is working with the U.S. Army Corps of Engineers and other partners on the Willamette River to identify how much water is needed for ecosystems and communities, and when it is needed. This information will be factored into the operation of dams managed by the Corps to improve water quality and habitat for fish and wildlife while continuing to meet human needs. 

The largest river system in Oregon and 13th largest in the U.S., the Willamette River and its tributaries support important runs of migratory salmon, trout and other fish. Its floodplains and backwaters provide important habitat for amphibians, birds and other wildlife.
The Willamette River Flow Management project is part of the Sustainable Rivers Project, a partnership between the Conservancy and the Corps working at eleven river basins around the nation to restore the natural connection between rivers and land by modifying the way dams release water. The project aims to better guide the operation of dams to benefit the environment and native species, while meeting needs of flood control, recreation and irrigation.

 River Flow fast facts:
  • Although freshwater ecosystems cover less than one percent of the world, at least 12% of known animal species inhabit freshwater environments.
  • In the United States, 40% of fish and amphibian species, 50 percent of crayfish and 70 percent of mussels are imperiled, largely by alterations to their habitats.
  • Dams, diversions, levees and other structures change natural flow patterns of rivers and streams. Over 5,500 large dams and tens of thousands of smaller dams are altering water flows across the United States. 

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