The Middle Willamette Watershed covers approximately 6,000 square miles and is home to the largest cities in Oregon such as Salem, Eugene, and Corvallis. The hydrology of the area is characterized by the Willamette River, which is fed by numerous creeks and rivers. The watershed also has a significant snowpack, which can lead to flooding during spring and summer months. Surface water quality in the region has been impacted by agricultural and urban development, leading to high levels of sediment, nutrients, and bacteria. Reservoirs in the area, such as Detroit Lake and Green Peter Reservoir, provide a significant source of water for municipalities and irrigation. Climatic trends in the watershed include increasing average temperatures and drier summers, which may exacerbate water quality issues in the region.