Dam Failure Case Study: Columbia River Levees (Oregon, 1948)

On May 30, 1948, rising floodwaters of the Columbia River breached a railroad fill acting as a levee and flooded the city of Vanport, Oregon. At the time, Vanport was Oregon’s second largest city and World War II’s largest federal housing project. Located in the marsh between the Columbia River and the Columbia slough, a system of levees protected Vanport from the floods of the Columbia River. At 4:17 pm on May 30th, Memorial Day 1948, a railroad embankment on the western end of the levee system collapsed under the pressure from the river, sending waves of water into Vanport. In less than a day, the nation’s largest housing project – and Oregon’s second largest city – was destroyed and 18,000 residents were displaced from their homes. Following the flood, the city was not rebuilt. The area is now home to a golf course, the Portland International Raceway, and recreational wetland areas.