Grand Coulee Bridge Grand Coulee Bridge The Grand Coulee Bridge, or Columbia River Bridge at Grand Coulee Dam, is a steel thru cantilever truss bridge built in 1934-1935. It carries Washington State Route 155 across the Columbia River immediately below Grand Coulee Dam, near the city of Grand Coulee, Washington. It was added to the National Register of Historic Places in 1982. The bridge was built to transport heavy equipment across the Columbia river during the construction of the dam, and thereafter as permanent highway bridge. As such, it was designed to carry a heavier load than was typical. The bridge is supported
Grand Coulee Dam of electricity. Each generator is supplied with water by an individual penstock. The largest of these feed the Third Powerplant and are in diameter and can supply up to . The dam's power facilities originally had an installed capacity of 1,974 MW but expansions and upgrades have increased generation to 6,809 MW installed, 7,079 MW maximum. Grand Coulee Dam generates 21 TWh of electricity annually. This means the dam generates about 2,397 MW of power on average, which results in a total plant factor efficiency of 35%. In 2014, 20.24 TWh of electricity was generated. Grand Coulee Dam's spillway is