Since the 1700s, when the human impact on salmon was limited to native fisheries, salmon have been increasingly affected by the Northwest's growing population and economy.

The first major European impact on the natives of the Columbia River occurred in the 1770s, when the first diseases struck native peoples. By the mid-1800s, European diseases reduced their population by 90% and the Columbia's resources were being exploited for the benefit of the new settlers. By the 1890s, dams were affecting salmon runs; hydroelectric and flood-control projects eventually reduced the area available to salmon by half. Salmon in the Columbia are also affected by grazing, irrigation, logging, mining, overfishing, pollution, urbanization, ocean conditions, and predators.

As the Northwest's population and economy grow, the future of wild salmon is uncertain. Plans for improving the status of salmon have become increasingly common, but many projects simply undo the damage caused by past generations of well-intentioned developers. An historical perspective is essential for understanding the current and future status of salmon and steelhead in the Columbia Basin.

How has the Columbia changed from 1770 to the present? These maps and graphs illustrate how humans have altered the river and how these alterations have affected salmon survival.

The Columbia Basin in 1770
The Columbia Basin in 1940
The Columbia Basin Now
Other Salmon Links

This information is available as a free Oregon Sea Grant publication.
To Index To Columbia River History To Regional Data To Related Sites To References

Updated:Wednesday, 11-May-2005 14:18:42 PDT
URL is