The Willamette River Floodplain contains deep, fertile, silty clay soils and supports forests of cottonwoods, alder, Oregon Ash, Bigleaf Maple, and Douglas Fir. Biologists estimate that there are 18 species of native amphibians, 15 reptiles, 154 birds, 69 mammals, and 31 fish currently breeding in the Willamette Basin. Thirty-six of these species have been identified by state or federal agencies as threatened, endangered, or species of concern. The main stem of the Willamette supports more than 35 fish species in some areas. Seven of the native species are listed as threatened, endangered, or sensitive.

The Willamette Floodplain Restoration Program is working with landowners along the Willamette River to create projects that decrease flood damage of farmland as well as addressing environmental concerns.