Snoqualmie Falls Hydroelectric Plant: Power Under the Falls

Snoqualmie Falls is famous for the view. Hidden behind it is a piece of engineering history. Plant 1 of the Snoqualmie Falls Hydroelectric Plant sits in a cavern 270 feet below and about 300 feet behind the falls. Completed in 1899, it was the first completely underground hydroelectric plant ever built in the world. [1]

It was the idea of Charles H. Baker. He was an engineer for the Seattle, Lake Shore and Eastern Railway and passed the falls often on the job. After the Panic of 1893 left him out of work, he decided to build the plant. With money from his family, including his father, businessman William T. Baker, he formed the Snoqualmie Falls Power Company and bought the falls and the land around them in 1897. [1]

Construction began in 1898. Workers built a cofferdam, then used steam-powered drills to sink a vertical shaft from the intake down to the cavern. The cavern is 200 feet long, 40 feet wide and 30 feet high. Four Pelton turbines were installed first. The first generator came online and began sending power to Seattle on July 31, 1899. By November 1 of that year the rest were running and power was also going to Tacoma. [1]

Baker did not keep the plant. In 1903 Seattle Electric Company bought his company, and that same year his father's death and money troubles ended his stake. A second powerhouse, Plant 2, was built in 1910 on the river bank below the falls. A rebuild costing $200 million began in 2010 and finished in mid-2014, adding new visitor centers, trails and a boardwalk. Together the two plants now have 53.9 megawatts of capacity, which Wikipedia describes as enough for 40,000 homes. [1]

Plant 1 is on the National Register of Historic Places, listed in 1976 as the Snoqualmie Falls Cavity Generating Station. In 1981 the American Society of Civil Engineers named it a National Historic Civil Engineering Landmark. Puget Sound Energy owns the plant. It sits just north of the city of Snoqualmie, about 22 miles east of Seattle. [1]