Subject
- Arsenic -- Environmental aspects -- Oregon -- Willamette River Region1
- Conservation1
- Douglas County (Or.)1
- Greater sage-grouse1
- Groundwater -- Oregon -- Willamette River Watershed1
- Groundwater -- Pollution -- Oregon -- Willamette River Region1
- Hydrogeology -- Oregon -- Willamette River Watershed1
- Inorganic compounds -- Environmental aspects -- Oregon -- Umpqua River1
- Powell, John Wesley, 1834-19021
- River sediments -- Oregon -- Tualatin River Watershed1
- River sediments -- Oregon -- Umpqua River -- Analysis1
- Tualatin River Watershed (Or.)1
- Water -- Pollution -- Oregon -- Tualatin River Watershed1
- Water quality -- Oregon -- Umpqua River1
- Water quality bioassay -- Oregon -- Tualatin River Watershed1
- Water-supply -- Oregon -- Lincoln County1