Upper North Fork Feather River Project

The Upper North Fork Feather River Project is a hydroelectric scheme in the Sierra Nevada of California, within Lassen and Plumas Counties.

[1] The project is one of several on the North Fork and its tributaries, forming a hydroelectric system so extensive it has been dubbed the "Stairway of Power".

[2][3] The project was conceived in the early 1900s under the Great Western Power Company to provide hydroelectricity and water storage for irrigation in the Sacramento Valley.

Great Western Power Company began to buy land in the valley for the future reservoir, but encountered bitter local opposition.

A rough one-way road was blazed from Greenville in the same year to transport workers and construction materials to the site, where a company town called Canyondam was established.

[5]: 101 [6] The construction of this reservoir, which at the time, had a capacity of 220,000 acre-feet (270,000,000 m3), ensured a steady water supply for the powerhouse and for irrigation during the summer.

A high dam on Butt Creek was built in 1924 to increase the total water storage and power capacity.

[6] The third project dam, Belden Forebay, was built on the North Fork in 1958 to serve as an afterbay for the Caribou powerplant.

[6] Six years later, in 1968, the giant Oroville Dam was completed on the Feather River as part of the California State Water Project, forming Lake Oroville, which flooded out most of the lower North Fork, including Big Bend Powerhouse and the Big Bend Dam.

[3] The last component of the project, Oak Flat Powerhouse, was built in 1985 to generate power from fishery releases, as federal law requires a minimum flow to be maintained in the otherwise dewatered river stretches between the dams.

The dam and reservoir control runoff from a watershed of 503 square miles (1,300 km2), whose headwaters lie in Lassen Volcanic National Park to the northwest.

[3] Water from Lake Almanor is diverted southwest through the short Prattville Tunnel to Butt Valley Powerhouse, completed in 1958.

[6] The dam on Butt Creek, a tributary of the North Fork Feather River located south of Lake Almanor, was completed in 1924.