Although the Willamette was , by the mid-20th century , heavily engineered and controlled by a complex system of dams , channels , and barriers , it experienced severe floods through the end of the century . Storms caused a major flood that swelled the Willamette and other rivers in the Pacific Northwest from December 1964 through January 1965 , submerging nearly of land . Before dawn on December 21 , 1964 , the Willamette reached , which was higher than the seawall on its banks in Portland . By this time , about 15 people had died as a result of the flooding , and about 8,000 had been forced to evacuate their homes
major flood
Christmas flood of 1964
Willamette River