Length: 5,223 feet or nearly a mile long
Height: 550 feet above bedrock, or 46 stories tall.
It contains nearly 12,000,000 cubic yards of concrete. That's enough to build a sidewalk 4 feet wide and 4 inches thick, twice around the equator.
During construction a world record for pouring concrete was achieved, and it still stands. Over 20 thousand cubic yards of concrete was placed in one 24-hour period.
The plentiful gravel deposits made by the Columbia River were used to build the dam.
The dam is expected to last until the next ice age (10,000 years); the hydroelectric facilities for a mere 500 years!
Six power stations are arranged along the east arm of the wall. Each has the capacity to carry two Colorado Rivers.
Snow melt replenishes the upstream water level 30 to 50 feet each season.
It is rarely necessary to allow spillage over the top of the wall due to high water levels. What you see coming over is likely in aid of maintaining downstream flows for the fish runs.