Lower Monumental Dam
The dam is located at the head of Lake Sacajawea, the reservoir created by Ice Harbor Dam. It is 3,791 feet long, with an effective height of 100 feet. The dam is a concrete gravity-type dam, with short earthfill abutment embankments. The eight-bay spillway is 572 feet long, and has eight 50-foot by 60-foot tainter gates.
Lake Herbert G. West: The lake extends up the Snake River for a distance of 28.1 miles to the tailwater of Little Goose Dam. It has a surface area of 6,590 acres, and is at elevation 540.
Powerhouse: The powerhouse has six 135,000-kilowatt units. Power generated through September 1996 was 76.8 billion kilowatt hours.