The Willamette River Basin is located in northwestern Oregon between the Cascade Mountains and the Coast Range. The basin comprises 11,500 square miles and is bordered by foothills and mountains up to 10,000 feet high to the south, east, and west. The Willamette flows north to the Columbia River, joining it just ten feet above sea level.
The Willamette River basin has been inhabited by humans for at least 10,000 years, providing sustenance for Native Americans, Euro-Americans, pioneers, and citizens alike. The waterway has provided vital transportation for people and goods. Increases in industrial use, sewage disposal, and population during the early 1900s to the mid-1900s compromised the river's capability to absorb waste and resulted in serious pollution of the main stem river. Despite continued population growth, ongoing cleanup efforts have resulted in improvement toward several measures of watershed health. While major efforts have addressed municipal and industrial sources of pollution, current river restoration efforts are focusing on nonpoint pollution from agriculture, storm
