Detroit Dam spillway gate
Detroit Dam, 45 miles southeast of Salem, Ore. sits across the North Santiam River. It has six spillway gates that are 42 feet wide by 31 feet tall. In 2020, as a part of Portland District's comprehensive dam safety program, staff completed an updated seismic hazard analysis for Detroit Dam to better understand the potential earthquake ground motions at the site. Corps engineers used this his hazard study to analyze the performance of the spillway gates and found the risk to be higher than we previously assessed. Structural analysis of the spillway gates has shown there is a possibility for buckling of the spillway gates' supporting arms, which could result in an uncontrolled release of water from the dam. Because Detroit Dam is located upstream of many communities including the state capital of Salem, Oregon, there is potential for devastating flooding to affect large portions of the narrow North Santiam River canyon and urban areas.