1873 Major anthropogenic physical disturbance Columbia River: First dam on Columbia watershed: Willamette Falls Locks Read More 25 JUN 0
1872 Major anthropogenic physical disturbance Columbia River: dredging a 2-meter deep channel from Portland to Lewiston commences Read More 25 JUN 0
1868 Major anthropogenic physical disturbance Columbia River: dredging a 5-meter deep, 177 kilometer channel to Portland commences Read More 25 JUN 0