THE HANFORD REACH OF THE COLUMBIA RIVER - A REFUGE FOR FISH AND RIVERINE WILDLIFE AND PLANTS IN EASTERN WASHINGTON

Eleven hydroelectric dams constructed on the mainstem Columbia River i n the Pacific Northwest since the 1930s have created large reservoirs that have inundated chinook salmon spawning beds and riverine islands used as nesting habitat by Canada geese. These same dams altered the f oraging habitats of wintering bald eagles and diminished habitats once occupied by native species of riverine molluscs and semiaquatic plant s. Today the only unimpounded section of the mainstem Columbia River i n the United States is the 82-km segment that flows through the US. De partment of Energy's Hanford Site in southeastern Washington. Here, th e Columbia River provides a refuge for native fish and riverine wildli fe, even though for nearly 50 years the Hanford Site was a major produ cer of plutonium and released radionuclides and heated water directly into the river, especially in the years 1944-1971. Plutonium productio n ceased in the late 1980s, and the future of native fish and riverine wildlife populations that use the Hanford Reach is uncertain. Only co ntinued surveys can evaluate changes in fish and wildlife populations as the mission of the Hanford Site changes to cleanup and environmenta l restoration and the site's land is released for other uses.