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Video by Chief Petty Officer Matthew Cole

McNary Dam

U.S. Army Corps of Engineers Walla Walla District

March 4, 2024 | 0:30

he dam is 7,365 feet long, rising approximately 183 feet above the streambed. It consists of a concrete structure with an earthfill embankment at the Oregon (south) abutment. The spillway is a concrete, gravity-type spillway dam. It is 1,310 feet long, and contains 22 vertical lift gates, each 50 feet by 51 feet. The crest is at elevation 291 feet mean sea level and is designed to pass a flood of 2,200,000 cubic feet per second. U.S. Army Corps of Engineers (USACE) has committed to spill more water over spillways instead of through turbines during its annual “spring spill” operations at dams on the lower Snake and Columbia rivers as well as expanding spill in the fall and early spring.